Car Terminology: Comprehensive Glossary From A to Z

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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Active Cylinder Technology ACT – Active Cylinder Technology, (ACT) is an engine technology that improves engine efficiency, reducing fuel consumption and associated emissions. The technology shuts down two of the four cylinders at low to medium rpm and reconnects these cylinders at higher revolutions to retrieve the engine’s full potential. This technique works at up to 130 km/h regardless of which gear is engaged.

Active Head Restraints AHR – Active Head Restraints is a system that comes into action only in a rear-end crash. The inertia caused by an impact from the rear presses the upper body into the back of the car. This movement triggers the back rest and lever, which bring the headrest forward automatically to decrease the distance between head and headrest. This reduces risk of injury by preventing stretching of the neck vertebrae. Once triggered, the system can be reversed at no cost.

Active Return – As part of electromechanical power steering, Active Return makes driving more comfortable by reducing the number of times you need to correct your steering. The positive centring and resulting steering torque offer a high level of steering precision, even at the smallest angles.

Active safety features – Active safety features are designed to prevent dangerous situations that can affect your driving, including situations that are unpredictable and external and those at the fault of the driver.

Adaptive Cruise Control ACC – ACC (Adaptive Cruise Control) makes your ride more comfortable by automatically accelerating and decelerating your car according to the flow of traffic and your selected driving style. Simply select your desired driving speed and distance from the car ahead (complying with statutory minimum distances) and activate the system via a control lever. In practice, ACC operates like an intelligent cruise control system which automatically maintains your desired distance, depending on your desired speed, using an advanced front radar system. If there is no car ahead of you, ACC operates like a conventional cruise control system.

Adaptive Front Lighting System AFS – Adaptive Front Lighting (AFS) ensures the best headlight setting for the road ahead. It automatically adjusts the angle of the beam to compensate the load weight and prevent your lights from dazzling drivers in oncoming traffic. Automatic headlight range adjustment comes as standard on most models with Bi-Xenon headlights.

Adjustable Lumbar Support – With individually adjustable lumbar support, you and your passengers can easily maintain a proper sitting posture. This is especially important during long trips, when the muscles can sag due to fatigue. Lumbar support relaxes tension on the spine to prevent pain or discomfort due to poor posture, cramping or existing back problems.

Adjustable Steering Column – The adjustable column lets you position the steering wheel at the perfect height and distance from your body, improving safety, comfort and visibility.

Aerodynamics – Efficient aerodynamics play a vital role in your car’s overall efficiency. The more aerodynamic your car is, the less drag it produces. Less drag means less effort is needed to push it through the air. Good aerodynamics lead to better performance and fuel economy.

Aerodynamic kits – Give your car a unique and sporty touch. Forming a key part of the accessories range, aerodynamic kits consist of a front spoiler, side skirts, rear apron and roof spoiler.

Airbags – Airbags are safety devices in vehicles. They are essentially inflatable cushions that quickly fill with gas during a crash. This rapid inflation helps soften the impact, reducing the risk of injuries by providing a buffer between you and the hard surfaces inside the car. In simple terms, airbags are designed to protect passengers in the event of an accident by cushioning and reducing the force of impact.

Airbag control unit – The airbag control unit detects and evaluates the severity of an accident and then triggers the appropriate restraint systems. Information is supplied to the unit by as many as six crash sensors. This includes acceleration sensors and a rotational speed sensor. The readings from these are used to evaluate and compare the signals from the other sensors. The crash signals are then sent to the airbag control unit and additional data systems to activate the hazard lights and interior lights, turn off the fuel pump and stop the engine. The restraint systems are also designed to achieve maximum effect according to accident type.

Air Conditioning System – An air conditioning system is a device that cools indoor spaces by removing heat and moisture from the air. It works by drawing in warm air, cooling it down with a refrigerant, and then circulating the comfortable, cool air back into the room. This process not only keeps the temperature pleasant but often improves the air quality, making your space more enjoyable during hot weather.

Air Drag – Air Drag is the force that resists a car’s motion as it moves through the air. When a car speeds up, it experiences more air resistance, meaning the engine must work harder. This force depends on the car’s speed, its frontal area, and how aerodynamic its design is. Formula: drag = car speed² x front surface x drag coefficient x (½ air density)

Air quality sensor – The air quality sensor is part of the air conditioning system. It measures pollutants, in the form of oxidisable or reducible gases, in the air outside your car. Oxidisable gases include carbon monoxide, hydrocarbons (vapours from benzene or petrol) and other partially burnt fuel components. If the quality of the outside air drops, the control system activates the Climatronic air recirculation mode, stopping polluted air from coming in and maintaining the quality of air inside the car.

Alcantara – Alcantara is synthetic leather made of a non-woven fabric consisting of polyester microfibres. Alcantara is similar to suede and is very durable, wrinkle-resistant and easy to clean.

All-round visibility – Visibility is essential for safe driving. All-round visibility lets you see the corners of the car’s bodywork as clearly as possible.

Angle of approach – The angle of approach refers to the transition angle from a horizontal plane to a slope. For cross-country cars, short body overhangs at the front and rear are helpful.

Anti-Lock Braking System ABS – Anti-Lock Braking System (ABS) is a safety feature in vehicles that prevents the wheels from locking up during heavy braking. It helps maintain traction and control, especially on slippery roads.

Anti-roll bar – The anti-roll bar is normally a U-shaped round bar, 10 to 60 millimetres in diameter. The middle section of the ‘U’ is attached crossways to the car body on pivoting rubber mounts with the ends joined to the suspension. Lever forces on one side act to balance the opposite side. Anti-roll bars improve tracking (the alignment of the car’s wheels), and therefore handling. At the same time, they also reduce body roll. The improved tracking makes cornering safer and more comfortable.

Anti-Theft Alarm System – An Anti-Theft Alarm System is a security feature in cars that helps prevent theft. When it detects any unusual activity, such as someone trying to break in, it emits a loud sound to scare off the intruder and alert nearby people. This simple yet effective system adds an extra layer of protection for your vehicle.

A Pillar – The forward-most roof pillar, forming the uprights that support the windscreen. The pillars are named alphabetically by order of placement from front to back of the car.

Aspherical exterior mirrors – Aspherical exterior mirrors have a dual, partially curved (convex) mirror surface. This increases the viewing area of the rear-facing mirror. When using aspherical mirrors, properly adjust the exterior mirror to fit your driving position to eliminate the blind spot almost completely.

Auto Hold function – The Auto Hold function is an extension of the electric parking brake and offers you more convenience and extra safety. Operated via the ABS/ESC hydraulic unit, it stops your car from rolling away accidentally when standing still or setting off. When you brake your car to a standstill position, Auto Hold retains the last-applied braking pressure. You can take your foot off the brake, and all four-wheel brakes will stay on. If the ABS wheel speed sensors detect any rolling, braking force is automatically increased until the car comes to a standstill again. As soon as you press the accelerator and, in the case of manual gearboxes, release the clutch, Auto Hold reduces the braking pressure.

Automatic Anti-Dazzle Interior Mirror – The automatic anti-dazzle interior mirror improves your comfort and safety while driving at night by preventing glare from cars behind you. It consists of a mirror and an electronic control with two photosensors. By means of the photosensors, the electronics detect light entering from the front and rear. If the light from behind is greater than that from the front, the mirror dims accordingly. Since you don’t have to operate the mirror manually, your hands can remain on the steering wheel, further increasing your safety.

Automatic Brake Release function – The Automatic Brake Release function is a feature in some modern cars that lets you start driving without having to manually disengage the parking brake. In practice, as soon as you press the accelerator—whether you’re on flat ground or facing a steep hill—the system’s sensors and controls automatically determine the best moment to release the brake. This makes your start smoother and more effortless.

Automatic Climate Control – Automatic Climate Control is an air conditioning system that maintains the manually pre-set interior temperature of your car at the desired level. It ensures you and your passengers feel comfortable, regardless of the weather conditions. The climate control system also prevents the windows from misting up, thanks to its dehumidifying effect.

Automatic headlights – Automatic headlights are lights on your car that turn on and off automatically depending on the surrounding light. They use sensors to detect when it gets dark—like at dusk or when you drive through a tunnel—and then switch on to improve your visibility. Once it becomes bright again, the sensors turn them off, so you don’t have to worry about manually managing your headlights.

Automatic Light-On – Automatic Light-On is a safety feature in many modern cars that automatically turns on your headlights when it gets dark—like at dusk or when you’re entering a tunnel. Instead of having to worry about manually switching on your lights, sensors detect low ambient light and activate the headlights, ensuring you have good visibility and that other drivers can see you. This simple convenience not only enhances your safety on the road but also minimizes driver distraction, letting you focus on driving.

Automatic Post-Collision Braking System – is a safety feature that kicks in immediately after a crash. When your car experiences an impact, sensors (and sometimes signals like airbag deployment) trigger the system to automatically apply the brakes. This helps slow the vehicle down quickly, reducing the risk of rolling into another object or vehicle after the initial collision. The goal is to prevent secondary impacts and minimize further damage or injury. This smart safety measure adds an extra layer of protection in an already stressful situation.

Automatic Three-Point Safety Belt – The Automatic Three-Point Safety Belt is a belt system that secures you safely in a car by anchoring you at three points—usually across the chest, over the shoulder, and across the waist. In the event of a sudden stop or collision, it automatically tightens to remove any slack, helping to keep you firmly in place and work with other safety features like airbags. This straightforward yet effective design is a key element in modern vehicle safety.

Automatic transmission – An automatic transmission is a system in a car that changes gears on its own, so you don’t have to manually shift gears or use a clutch. It uses sensors and hydraulics to decide when to shift, making driving smoother and easier, especially in stop-and-go traffic. This simplicity is one of the reasons why many drivers prefer cars with automatic transmissions.

Automatic window opening – Electrically-operated windows are an important comfort feature in modern cars. Among other things, they let you open or close the passenger window or rear side windows. The control buttons for the power windows are usually located on the doors, but sometimes they can be found in the central console. In most cases, the electric windows can be blocked by a child safety lock.

Axle support – Axle support is the assembly of parts that hold a car’s axle and help keep the wheels stable. In simple terms, it includes components like the axle itself, a stabilizer, and sometimes elements of the drive or steering systems. Together, these parts work to reduce vibrations and keep your ride smooth and steady.

Back-up horn – A back-up horn is an extra horn in your car that works separately from the main one. It’s part of the anti-theft system and sounds off if someone tries to break in. It can also give a short beep when you lock or unlock your car with your remote. This feature adds an extra layer of security, although it might be disabled in some countries.

Battery – The battery is a rechargeable device that stores electric energy through chemical reactions. It provides a surge of current that starts the engine. Once the engine has started, the engine-driven alternator maintains the battery’s charge, powering your car’s electrical systems. Car batteries provide a nominal 12-volt potential difference by connecting six galvanic cells in series.

Battery Energy Management System – The Battery Energy Management System is like a smart guardian for your car’s battery. It keeps track of the battery’s charge level and temperature to ensure there’s always enough power to start the engine—even if the car sits unused for a while. If it notices the battery is running low, it might adjust the engine’s idle speed to help recharge the battery or temporarily shut down some power-hungry features. Overall, it’s all about keeping your battery healthy and avoiding unexpected dead batteries.

Bi-Xenon – Bi-Xenon headlights are a special type of Xenon headlight. Both dipped and main beams can be produced with one headlight. With dipped headlights, a movable shutter cuts off a portion of the light beam. If the shutter is triggered by an electromagnet, it retracts from the light beam, thus enabling the main beam to come on.

Blind Spot Detection – This technology makes it easier and safer to change lanes by detecting potential vehicles in your blind spot. Blind Spot Detection uses an LED warning light in the exterior mirror to alert you if any cars are approaching from behind when you change lanes.

Bluetooth – Bluetooth creates the conditions that allow your different portable devices, such as mobile phones, laptops or personal digital assistants (PDAs), to connect wirelessly. The connection exists as a radio link between the devices’ transmitting and receiving units. The data transfer takes place on a worldwide, royalty-free, transmission frequency of 2.4 GHz (Gigahertz) with a data transfer rate of up to one megabit per second. The interface transmitting power is 1 Watt. This permits around 10 metres to be covered, in other words, enough space to crosslink individual devices inside your car. The low transmitting power enhances device security because it prevents “eavesdropping”. It’s also immune to interference from electromagnetic radiation.

Bodywork construction – The majority of modern cars have a self-supporting body. The body consists of several hundred different preformed sheet metal parts, sheet metal hollow bodies and shells. On modern bodies today, up to 230 different types of steel are used with material thicknesses between 0.8 and three millimetres. In addition to different sheet thicknesses, a variety of steel alloys are used. Nowadays, we distinguish between normal, toughened, high-strength and ultra high-strength steel. This allows the expenditure on materials and therefore the car weight to be reduced. Attachments such as doors, bonnets, wings or hatchbacks are bolted to the body. Custom-made components, so-called “tailored blanks”, ensure lower material costs with the same stability. In addition to the lower weight, which has a positive effect on fuel consumption, they also offer the advantage of easier installation and increased stability.

Bodywork galvanising – The safest way to protect steel against corrosion is by galvanising it. During galvanisation, the zinc does not form a loose layer on top of the sheet metal components, but rather becomes a stable compound insensitive to damage on the surface. Galvanic zinc plating, which results in a very thin layer of less than 20 microns (millionths of a metre), allows finer surfaces to be treated. It is especially suitable for the visible surfaces of the body. A galvanised or fully galvanised body reduces financial risk, as it ensures safety, value maintenance and service life over a long period. Galvanising guarantees optimal protection against corrosion, ensuring structural integrity over the car’s entire lifetime.

Bodywork platform – The body platform of a car is the most complex and therefore most expensive assembly when developing a new vehicle. The platform forms the basis for all relevant parameters that later determine the handling characteristics, comfort or interior space: wheelbase, track width, engine, chassis design or interior. The development of a new car platform is what requires the highest investment in the context of car development. This is why successful automotive companies are going over to manufacture as many different models as possible on one single platform. The customer thus receives a technically mature, reliable product of the highest quality at an affordable price.

Bodywork rigidity – Bodywork rigidity is one of the keys to the safety, comfort and durability of a car. The less a vehicle “twists” on uneven road surfaces or when cornering at speed, the safer its handling characteristics are. Rigidity varies with different body shapes. In general, the structure of an open car can never achieve the rigidity of a closed saloon, an estate car or a van. The occupants become aware of high body rigidity by the extremely low interior noise level and the quality of a precise interior finish.

B Pillar – The roof support pillar located in the car’s midsection, between the A and C pillars. The pillars are named alphabetically by order of placement from front to back of the car.

Brake Calipers – This is the component of the braking system that straddles the brake disc and houses the brake pistons and brake pads. When the brakes are applied, brake fluid pushes the pistons in the caliper against the brake pads, which squeeze the brake disc and stop it.

Brake Disc Cleaning System – The brake disc cleaning system is designed to increase safety in heavy rain by applying the brake pads to the brake discs at prescribed intervals in order to wipe away the unwanted film of water. This produces the full braking effect faster and shortens braking distance.

Brake fade – Fading refers to a reduction in braking power when the brakes are used heavily, such as continuous braking during downhill driving through mountains. The cause of fading is poor dissipation of the frictional heat generated during braking and, in extreme cases, can lead to red hot brake discs. Fading can lead to distortion of the brake discs or drums, or to the formation of vapour bubbles in the brake fluid.

Brake fluid – Brake fluid mainly consists of the toxic and corrosive substance polyalkylene glycol ether together with special additives. It’s used to transfer pressure in hydraulic brake systems. To prevent the formation of vapour bubbles under high brake loads, its boiling point is very high (290°C). The fluid’s hygroscopic (i.e. water-attracting) properties require regular checks at prescribed maintenance intervals and a change of fluid if necessary. Even a small amount of water content lowers the boiling point significantly and may lead to the formation of bubbles that prevent applying full brake pressure. This would increase braking distances as a result.

Brake master cylinder – The master cylinder converts brake pedal movement into hydraulic pressure. The activation of the brake pedal is based on the principle of the lever: the low pedal force is increased many times over by the master cylinder. The resulting hydraulic power is then transferred to the individual wheel brake cylinders via a branching main line.

Brake pads – Brake pads are the friction pads on a brake caliper that clamp together on either side of a brake disc to slow or stop the wheel.

Brake servo – The brake servo reduces the force you need to apply to the pedal when braking. The negative pressure in the engine’s intake manifold is used to achieve this. Both pneumatic and hydraulic systems exist. In cars with power steering, the servo pump may be used for this purpose.

Brake Wear Indicator – A sensor mounted in the brake pad that warns you when the pads have worn out to the point that they need replacing. When this happens, the Brake Wear Indicator sensor grinds against the brake disc and a warning light appears in the instrument panel.

Brakes – A car’s braking system plays a crucial role in its overall safety: the more effective the brakes, the shorter the stopping distance. The brake size must be matched to the car’s engine power, weight and theoretical top speed. For reasons of safety, modern cars are fitted with two brake circuits serving diagonally opposite wheels on two axles. Some models ensure sufficient stopping power through a combination of disc brakes at the front wheels and drum brakes at the rear. Higher-powered and mid-sized models tend to use more powerful, internally ventilated discs at the front, as well as fitting disc brakes at the rear. Currently, the minimum standard specification for vehicle braking systems includes: Anti-Lock Braking System (ABS), brake servo, Electronic Brake-Force Distribution (EBD) and Electronic Stability Control (ESC).

Camber – Camber refers to the lateral inclination of the wheels in the driving direction. The camber is positive if the top of the wheel is angled outwards. A positive camber reduces the bodywork vibration. If the top of the wheel is angled inwards, the camber is negative with the effect of increased lateral guidance when cornering.

Camshaft adjustment – The camshaft is a shaft that uses projections (cams) to open and close the valves that let the air/fuel mixture into the engine and let the exhaust escape. As the camshaft rotates, it operates the valves at the right time and in the right order to control the charge cycle. Camshaft adjustment varies the opening times of the valves to suit all operating conditions. This ensures ideal charge cycles within a wide range of engine speeds and loads. Fuel consumption and pollutant emissions are reduced, while torque and smoothness are increased. During continuous camshaft adjustment, the timing of all the valves, driven by the respective camshaft, can be shifted in the same direction. This means that in engines with a double overhead camshaft, it is possible to influence the size and positioning of the valve opening overlap, thus enhancing the characteristics of full-load and part-load operation.

Controller Area Network CAN – The electronic components of a car include more and more functions over time. Conventional wiring techniques with long lines can no longer cope with this information exchange, requiring use of the CAN databus. The term Controller Area Network (CAN) refers to a serial bus system developed for automotive use. The CAN bus provides digital data exchange between sensors, actuators and control units, ensuring that several control units process the information from a sensor and that actuators can be controlled accordingly. In addition to short cable routes, one particular advantage of the CAN bus is that if one component fails, the rest of the system continues to function, thus significantly reducing the risk of total failure. More and more well-known electrical systems are being controlled via the CAN databus, improving safety and comfort. For example, the power-free light switch in the Leon. Simply select the type of lighting and the controller supplies the lamps with the necessary operating power. This allows functions such as the Coming Home feature to work. Because of the varying repetition rates of the signals and the ensuing volume of data, CAN bus systems are divided into three categories: 1) The Drive CAN bus transmits, among other things, the signals from the engine control unit, the transmission control and the ABS/ESP unit. 2) The Comfort CAN bus is crucial for climate control. 3) The Infotainment CAN bus is responsible for the signals from the car radio with speed-sensitive volume adjustment.

Chassis – The chassis decisively determines the driving safety and comfort of a car. Its central components are the suspension springs and dampers. The chassis ensures that the wheels maintain constant contact with the road. A wheel can only be controlled if it’s in direct contact with the roadway, i.e. generate propulsion, deceleration or a change of direction. Even the tiniest bump in the road can cause a wheel to “take off”, just like when the load is taken off the outside wheels in the camber of a bend. Since wheel and suspension have a certain mass, inertia prevents the wheel from immediately falling back onto the road surface. The springs ensure that contact with the road surface is restored as quickly as possible. And dampers reduce the vibration of the wheel so that the wheel does not continue to oscillate.

Caster – When viewed from the side, caster is the tendency of the front wheel to pivot on its axis towards the rear. The effect is comparable to that of a tea trolley in which the wheels automatically adjust to be pulled in the same direction. At high speeds, caster ensures the directional stability of the car.

Catalytic converter – A catalytic converter turns harmful emissions from the car’s exhaust into less harmful gases before they are pumped out into the atmosphere. It contains a chemical catalyst (usually precious metals, such as platinum and rhodium), ceramic or metallic carrying materials, casing and various regulatory devices for controlling the process. Depending on the design, the catalytic converter oxidises carbon monoxide to carbon dioxide and water and/or reduces nitrogen oxides to nitrogen and oxygen gas. Efficient catalytic converters reduce the levels of pollutants in exhaust gas by up to 90%. Cars use three-way catalytic converters (for petrol engines) and oxidising catalytic converters (for diesel engines), featuring up to 2 main and 4 primary converters, depending on the engine.

Cruise Control System CCS – The Cruise Control System (CCS) offers you extra comfort, especially on long journeys at constant speed. It also helps you comply with the stipulated speed limits (such as when passing through roadworks on the motorway) and reduces your risk of accidentally speeding. The CCS is activated by buttons on the left-hand control stalk. Using the buttons, your speed can be slowly and almost seamlessly varied. To turn off the Cruise Control, simply apply the brakes.

Central locking – An essential comfort and safety feature is the central system that locks and unlocks the car doors, luggage compartment lock and fuel filler cap. You can lock all facilities using only one key, even while driving.

Centre differential – The 4Drive four-wheel drive system features a centre differential between the front and rear axles to compensate for the different wheel speeds between the axles from different cornering radii. This prevents torsional stresses in the drive train and automatically distributes the driving forces. Essentially, the wheels with better traction receive more power, increasing directional stability and making your driving more effective and safer.

Charging – In engine design, charging refers to a simple principle: increasing the power of the engine by supplying air at increased pressure, thereby improving combustion. Whereas in conventional, naturally aspirated engines, the combustion air is simply sucked in from the environment during the intake stroke, with supercharged engines it is first compressed and then delivered to the engine. This allows considerably greater air mass and more efficient fuel consumption for the same volume. Thus, power and torque can be significantly increased at the same revolutions and with the same engine capacity.

Childproof lock – To prevent the rear doors from being operated from inside the car, the child door lock can be activated by means of a button (as part of the central locking system) or via mechanical adjustment. If fitted, the rear electric windows and optionally the rear cigarette lighter can also be protected against unintentional use. This is intended to minimise the risk of children harming themselves or other road users.

Child restraint systems – The rapid growth of a child from infancy up to the age of twelve years makes it impossible to provide one restraint system that meets all the stages of the child’s development to the same degree.

Cylinder capacity – Cylinder capacity refers to the volume of a cylinder between the top dead center inside the cylinder head and the bottom dead center of the piston. The engine capacity is the sum of all the capacities of all the cylinders taken together, depending on the number of cylinders. The capacity specified in the car registration document refers to the engine capacity and is measured in cubic centimeters.

Climate Control – The Climate Control air conditioning system regulates the temperature inside the car. Simply select your preferred temperature setting, and the system adjusts blower speed and operates the air vents automatically. The system’s electronic control monitors key influences, such as the position of the sun and the outside temperature, and adds more or less cool air accordingly. Integrating the control unit into the CAN databus means extra features can be added. These include the automatic switch to air recirculation mode whenever the windscreen is washed, preventing unwanted smells from entering the car. Climatronic also has a defrost function to clear misted or iced-up windscreens. If the outside temperature is above 0°C, the cooling system cuts in to dry the air before it’s heated.

Climatic – The Climatic System is a semi-automatic air conditioning system that automatically regulates the temperature of the fresh air being supplied according to the pre-set temperature. You can also adjust the air distribution and fan speed. The Climatic System features an interior sensor to measure the current interior temperature. The electronic controller regulates the temperature of the fresh air supplied in order to reach the specified value as quickly as possible and then maintain it. Air conditioning is not only important for comfort, but also for safety. At high interior temperatures, the driver’s attention decreases significantly. This is why we offer the Climatic system in almost all models.

CNG – Compressed natural gas (CNG) engines are designed to function both with petroleum-based fuels and with liquefied petroleum gas (LPG), i.e. propane, butane and their mixtures. This combination provides efficient combustion and thus equivalent handling characteristics. Each fuel type has its own individual fuel rail. If the CNG is used up, the engine automatically switches over to petrol mode. In addition, you can select petrol or CNG mode by means of a switch.

Collapsible safety steering column – The collapsible safety steering column consists of several mechanical components which, in the event of a frontal collision, ensure that the steering wheel cannot penetrate the interior of the car and the hazard zone of the driver’s head and thorax. It consists of an outer and inner casing tube that stores a spindle. Thus, the steering shaft is shortened in a similar way to a telescope. Furthermore, during a collision this linkage decouples the steering wheel movement through additional joints and ensures that the airbag housed in the steering wheel maintains the best possible position in front of the driver. We equip all our models with this important safety feature.

Comfort blinkers – With the comfort blinker function, the indicator stalk needs to be touched only once for the direction indicators to flash three times. The comfort blinker function increases safety and convenience. For example, when driving on the motorway, the system is especially useful because the indicator stalk needs to be tapped only once to clearly signal a lane change to other road users. The comfort blinker function is made possible through the use of a power-free light switch.

Comfort Closing – Comfort Closing lets you simultaneously close and lock all electric windows (including the panoramic sunroof), in addition to door locks and the fuel filler cap, via the remote control. Only the appropriate button on the ignition key needs to be kept pressed. If the locking button is released, the operation is interrupted immediately. The function can be used in reverse when opening the car. Comfort Closing and Opening can also be done via the door lock. To do this, the key needs to be turned to and kept in the respective position for opening or closing. The process stops immediately if the key is released.

Comfort dimension – The comfort dimension is the measurement of a car’s effectively usable interior length. It is measured from the rear seat backrest to the driving pedals. The reference points for the comfort dimension are the position of the rear passenger’s hip and the position where the driver’s heel rests on the accelerator.

Coming Home function – The Coming Home function makes it easier to see your surroundings when you get out of your car in the dark. After leaving and locking the car via the remote control, the headlights continue to shine for about another two minutes and thus ensure a brightly lit area around the car, a considerable gain in terms of safety and comfort in the dark.

Common rail – The term common rail is used to refer to a certain type of direct fuel injection. With common rail, pressure generation and fuel injection are separate processes. A separate pump, installable anywhere in the engine, continuously generates pressure which is stored in a distributor pipe. The injectors of all the cylinders are connected in parallel with the pipe, called a common rail. A constant pressure is continuously available at the injectors of all cylinders. The amounts and timings of the injected fuel are controlled by solenoid valves on the individual injectors.

Convenient Open-Close function – When the car is locked or unlocked from the driver’s or front passenger’s side, the side windows can be opened or closed at the same time. Press and hold down the Open or Close button on the remote key and all the windows (including the panoramic sunroof) respond. When the button is released, the process stops. This also happens if you turn the key to the unlock position in the door and hold it there. Furthermore, the windows close when you turn and hold the key in the closed position. Releasing the key stops the process.

Cooler – The combustion of fuel in the engine generates heat which must be dissipated via the cooling system. The cooling circuit gets rid of engine heat by means of the radiator. The cooling system must also be designed to allow the engine to warm up as quickly as possible after a cold start. For commercial cars, liquid engine cooling has become the most accepted system. Only with the help of “water cooling” can we further improve the cleanliness of exhaust gas, reduce fuel consumption, increase engine life and reduce noise for enhanced comfort and environmental protection.

Cooling circuit – The cooling circuit includes all thermally-stressed areas of the engine. The coolant circulating in the cooling circuit dissipates the heat produced during combustion and ensures a constant temperature level in the engine. In order to maintain the operating temperature as quickly as possible after starting, the cooling performance during the engine’s warm-up phase must remain as low as possible. For this, a small cooling circuit is sufficient. A large cooling circuit is required only after reaching the operating temperature. The control of the two circuits is provided by a thermostat which switches from the small to the large circuit at 80 to 90°C. It’s important that the cooling circuit is designed to ensure this constant temperature even at peak loads and with extreme ambient temperatures. Nowadays, a complex mixture of water and various additives is used as a coolant, which not only reduces the freezing point of the cooling liquid, but also increases the boiling point to 120°C. Added inhibitors have the task of preventing corrosion on the various metals which the cooling liquid flows around, e.g.: aluminium cylinder heads.

Cornering lamp function – The cornering lamp function is activated when turning. Depending on the steering angle, the fog lights swivel left or right. They illuminate the area to the side of your car, considerably increasing safety in the dark or while driving in poor lighting conditions.

Corrosion protection – The most reliable method of protecting sheet steel against corrosion is galvanising, which is a surface coating of metallic zinc on steel. The zinc undergoes a reaction which creates a stable compound that is immune to surface corrosion. This compound forms a physical and electro-chemical barrier to rust. Sheet steel can be galvanised on one or both sides. Galvanisation is applied in very thin layers of less than 20 micrometres and is used primarily to treat finer surfaces, such as the visible surfaces of your car’s body. Body galvanisation helps maintain a vehicle’s safety, value and serviceability.

C Pillar – The C Pillar is the third roof pillar and is located between the B and D pillars. The pillars are named alphabetically by order of placement from front to back of the car.

Crankshaft – In a reciprocating engine, the crankshaft is responsible for the crank mechanism. The crank mechanism converts the vertical movement of the piston to a rotational movement. The connection between the crankshaft and piston is formed by the connecting rods. Their reciprocal movement compensates the off-sets of the crankshaft. Extreme forces – torque and bending loads – act on the crank mechanism. These forces undergo extreme changes in very short time intervals. The resulting vibrations place the crankshaft under great stress. A high outlay of development and extreme precision in manufacturing technology ensure the crankshaft continues to function seamlessly over a long period.

Crash sensors – Crash sensors need to detect a collision and convert it to usable signals within milliseconds. The accelerating forces acting on the sensors after a collision can be as high as 100g (100 times the earth’s gravitational force). When a car is stopped abruptly by an impact, all bodies or objects that are not firmly fixed to the car will continue to move at the impact speed. The sensors measure this acceleration and relay it to the control unit as usable data.

Crash tests – Crash tests are used during new car development to optimise occupant protection. In these, prototypes of cars further along in the production process are used to simulate different types of accidents. The aim is not only to improve occupant protection and reduce forces acting on the passengers in an accident, but also to reduce the risk of injury to other road users (pedestrians, cyclists, etc).

Crumple zones – Crumple zones are part of the tough safety shell around your car, helping to protect you and your passengers in the event of an accident. Crumple zones are designed to absorb impact energy during a collision so that most energy is dissipated across these zones, and not in the passenger compartment. The strong outer shell comes with front and rear crumple zones that help to absorb the impact of a crash, increasing the safety of the car’s occupants.

CUP port – The CUP input is a combined USB and aux-in input for connecting external devices, such as your MP3 or CD player.

Daytime driving lights – Many daytime accidents are caused by a failure to recognise other road users in time. To prevent this, you can use a passing beam or separate daytime driving lights (mostly LED).

Dynamic Chassis Control DCC – Dynamic Chassis Control (DCC) is an innovative system that allows you to choose your driving style via a button in the central console. It offers three settings: Normal, Sport and Comfort. For each mode, the system operates the electrically regulated dampers and steering. In Sport mode, for example, the dampers are stiffened and the steering feedback is greater. This provides a driving experience like that of an agile sports car. The damping also adapts itself to the respective road conditions. Each shock absorber is connected to a control which calculates the optimal setting for each wheel using sensor data and other information received from the steering, braking, engine, transmission and driving assistance systems. This allows the DCC to continually react (up to a thousand times per second) to bumps in the road, changing lanes or winding roads. This reduces pitch and roll motion and provides optimal settings for every driving situation.

Deformation zones – In the event of an accident, impact absorption or deformation zones are designed to help protect everyone inside your car.

Diadem bulbs – Diadem bulbs are coated with a special opalescent surface that shines in a silvery fashion, even when inactive. Only during signal operation, for instance when flashing, does the lamp light up with its characteristic yellowish-orange colour. The advantages of diadem bulbs are their higher intensity and longer service compared to conventional bulbs. In addition, the silvery-white surface barely contrasts with the rest of the headlight, thus improving the overall look for modern, clear-glass headlights in particular. Diadem bulbs are approved for use throughout Europe.

Diesel direct injection – In diesel direct injection, fuel is injected directly into the combustion chamber. The direct injection diesel engine is currently the most efficient engine thanks to its high efficiency factor. In diesel direct injection, there are various ways to optimise the combustion process. These days, the common rail and pump-line-nozzle system have become established, along with the pump-jet system.

Diesel engine – The diesel engine is a piston engine with internal mixture formation and autoignition. Due to the high compression, the air temperature in the combustion chamber rises from 600 to 900°C. After the fuel has been injected, the fuel-air mixture ignites by itself. Diesel engines operate with different injection methods: pre-chamber, swirl chamber or direct injection.

Diesel particulate filter – Diesel particulate filters reduce the number of soot particles contained in the exhaust gas of diesel engines, thus ensuring even fewer emissions and more environmentally-friendly engine performance.

Differential – The differential compensates for different wheel speeds of driven axles. Different wheel speeds occur when cornering because one wheel of an axle travels a longer path than the other. In the process, the outside wheel rotates faster than the one on the inside of the bend. Speed compensation of the driven axles in most cases is taken care of by a bevel gear differential. A limited-slip differential directs power to the wheel with the better traction and prevents the other wheel from spinning freely.

Differential lock – In certain driving situations, such as when cornering, different wheel speeds occur. For example, when taking a corner, the wheels on the outside of the bend rotate faster than those on the inside of the bend. A differential compensates for these differences in wheel revolutions between the wheels on driven axles. Put simply, the wheels that have to cope with the greater number of wheel revolutions are allowed to freewheel to compensate for the difference in revolutions. A differential lock uses electronic signals to briefly interrupt the function of the differential mechanically. In addition, it connects the respective wheels to ensure that up to 100% of the drive power is directed to the wheel that has the best grip. The exact amount of air resistance acting on a car can only be calculated when the drag coefficient and the end face of the motor car (the projection of its front view on a surface) are specified.

Digital Audio Broadcasting DAB – DAB stands for Digital Audio Broadcasting. With digital radio, you can listen to your favourites in crystal-clear digital sound quality. The stations available depend on your location, but national stations are readily available.

Digital Cockpit – The Digital Cockpit is a safety feature that also generally improves the driving experience. The LCD Digital Cockpit puts all of your car’s vital information, including maps and driver assistance features, right in front of you. By consolidating this type of information within the information panel, driver distraction is minimised. The display itself uses a new variant of the traditional LCD screen, equipped with a thin film transistor. The new display technology improves image quality and contrast, making it easy to see even in brightly lit environments.

Dynamic cornering light – The dynamic cornering light forms part of the Bi-Xenon headlights and pivots with the steering angle (as opposed to the cornering light, which is switched on). The light cone of the dipped beam follows the course of bends and illuminates them much better. Due to the improved field of vision, the driver can perceive bends better and react faster to any obstacles or unexpected situations.

Dynamic headlight levelling – The dynamic headlight levelling control continuously and automatically adjusts the setting of the Xenon and Bi-Xenon headlights. This takes into account both the changes that are caused statically (load weight and distribution), as well as effects caused dynamically resulting from acceleration and deceleration. The advantage of dynamic headlight levelling is that it compensates for the change in headlight range caused by the inclination of the car body during acceleration or braking, so the illuminated area remains virtually constant. This ensures good visibility for you while driving and helps to prevent dazzling oncoming traffic.

Dynamic route guidance – The navigation system uses the traffic information transmitted via Traffic Message Channel (TMC) for dynamic route guidance. If the navigation system receives a message about traffic congestion or road closure on your planned route, it checks whether the affected area can be avoided and, if you request it, will direct you to an alternate route where possible.

Dynamic shift program – The dynamic shift program is a feature of automatic transmission. The gearbox control unit automatically selects the best gear based on engine map data and your current driving situation. The selection considers your current speed, the weight of a towed trailer and whether your car is travelling up or downhill. The program also adapts to your driving style and adjusts the gearshift points accordingly. For example, if you have a sporty driving style, the engine will be allowed to rev higher through the gears. If you use the accelerator more lightly, however, the gearbox will change up earlier. This adaptation doesn’t affect the kickdown function, which is available in every situation. By selecting the correct gear, gearboxes with dynamic shift ensure optimal engine output and keep fuel consumption and emissions low.

Directional stability – Several conditions in your car are responsible for directional stability. For example: the position of the wheels on their suspension, wheelbase, track width, steering, tyres and even bodywork and aerodynamics. Directional stability is especially important for spontaneous, easy steering response. Spoilers increase directional stability, including at high speeds, for enhanced overall safety.

Disc brake – The disc brake comprises a brake caliper with friction blocks on both sides. Compact and low in weight, it achieves a more uniform effect and better control with respect to drum brakes. There is a difference between a fixed caliper disc brake and a floating caliper disc brake, depending on the type of guidance or caliper mounting. Fixed calipers encompass the disc brake with a rigid housing. This means the position of the caliper to the disc brake is fixed. Opposite pistons press the brake pads against the disc brake. Fixed caliper brakes are known for having a precise pressure point and very high braking performance. In the floating caliper disc brake, the piston acts directly on your car’s mounted brake pad. The movable caliper presses the outer brake pad when braking. Some benefits include its space-saving design and favourable thermal behaviour. Although the temperature of disc brakes may increase up to 500° C, they are unlikely to fade. Internal ventilation is often used to cool the front disc brakes more effectively.

Door handles – Car door handles are external mechanisms that allow occupants to open and close vehicle doors.

Dot matrix display – Dot matrix displays are LED or LCD monochrome displays for text or simple graphics. Each character is generated through a pattern of dots in 5 columns by 8 to 11 lines. Some dots are bright, while others are dark. This creates the appearance of the character.

Downsizing – Engine downsizing is the trend in the automotive industry to build smaller and more fuel-efficient engines without impairing efficiency. The key strategy is to replace cubic capacity and the number of cylinders through technical innovations such as charging or direct injection. A modern, turbocharged four-cylinder engine often achieves significantly better power and torque than a conventional six-cylinder engine. The greatest advantage of downsizing is that engines become more economical and environmentally-friendly without losing power.

D Pillar – The D Pillar is the back roof pillar and forms the uprights that support the rear window. It’s located after the A, B and C pillars. The pillars are named alphabetically by order of placement from front to back of the car.

Drag coefficient – The drag coefficient is often expressed as its scientific abbreviation: Cw. It’s usually used in connection with a car’s aerodynamic properties. The smaller the Cw value, the more streamlined the car is built. Various factors influence the drag coefficient, such as the body style (saloon car, estate car or hatchback). Small gap and joint dimensions reduce turbulence and favour a low drag coefficient. Even the underbody design has an effect. The exact amount of air resistance acting on a car can only be calculated when the drag coefficient and the end face of the motor car (the projection of its front view on a surface) are specified.

Drive concepts – Modern cars commonly use three drive designs: front-wheel drive, rear-wheel drive and all-wheel drive. In front-wheel drive, the front wheels transfer the engine’s driving power to the road. This is currently the most widespread drive system. Its advantages include the space-saving installation of the engine and transmission and easy manoeuvrability while driving. In the case of rear-wheel drive, also known as standard drive, engine power is transmitted to the rear wheels. This requires a drive train from the engine at the front to the axle at the rear. This means the drive train, tunnel and rear axle differential limit the space available in the interior and luggage compartment. Rear-wheel drive has advantages when transferring high engine output. However, cars with rear-wheel drive tend to oversteer, which can be difficult to correct. All-wheel drive has established itself not only in off-road cars, but also in many passenger cars. A modern four-wheel drive system is particularly useful in powerful, sporty models in order to safely apply high driving forces to the road surface.

Driver and passenger airbags – Driver and passenger airbags are designed to protect against head and chest injuries in the case of a frontal collision. Their full effect is obtained only in combination with the seat belt. The driver airbag is integrated in the steering wheel’s impact absorber. The front passenger airbag is located in front of the seat in the cladding of the dashboard. If triggered, the cladding breaks along seams intended for this purpose. If the electronic triggering device’s sensors detect a crash above a certain collision speed, they ignite the airbag’s pyrotechnic gas generator. The gas suddenly releases to fill the air cushion before the body strikes it.

Drive shaft – In a front-wheel drive car, the drive shaft transmits the torque of the transmission to the wheels. In a four-wheel drive car, the drive shaft also transmits power from the transmission to the rear axle.

Drive Profile – Different driving modes. Each profile influences the responsiveness of the engine, the steering, the ambient lighting and the engine sound.

Drum brakes – The drum brakes are made up of a brake drum and two brake shoes which press the pistons of one (or two) brake cylinder(s) against the rounding of the drum brake. In the case of a heavy load, heat causes the drum to expand, which may lead to fading. Due to the limited loading capacity, drum brakes are particularly suitable for rear axles.

Dual-clutch transmission DSG – Dual-clutch transmission, also known as direct-shift gearbox (DSG), represents a modern evolution of the transmission assembly. The direct-shift gearbox has two wet clutches which use two drive shafts to operate respectively the 1st, 3rd, 5th and reverse gears (clutch 1) or the 2nd, 4th and 6th gears (clutch 2). During a gear shift, the next gear is preselected but not yet engaged. Within three to four hundredths of a second, one clutch opens while the other closes. In this way, the gear shifts are performed imperceptibly for the driver and without any interruption in traction. Depending on driving style, intelligent control electronics enable fuel savings of up to 10% compared to a 6-speed manual transmission.

Dual-Diagonal Brake System – For safety reasons, the hydraulic brake system is divided into two independent brake circuits. Two diagonally opposite wheels form one brake circuit. This means that each brake circuit acts on one front wheel and the diagonally opposite rear wheel. If one of the circuits fails, the second ensures residual braking. This stabilises the car and prevents spinning by means of a negative scrub radius.

Dual tuner with phase diversity – The diversity dual tuner (with phase diversity) ensures optimal radio reception. The received signal is passed from two antennas to two independent tuners, and finally combined in a digital processor. One of the two tuners scans the entire frequency range periodically for receivable channels. This keeps the channel list up to date while driving. If interference occurs, the tuner can switch to alternative frequencies immediately. The diversity tuner also offers a special advantage, even with Multipath. Interference that would usually otherwise occur is prevented by the fact that divergent signals are added out of phase. Even stations with a very weak signal can be received free of noise, since the two aerials work like a directional antenna.

E10 – Here the E stands for ethanol or bioethanol. E10 refers to petrol (super grade), which is blended with a higher proportion of ethanol (10%) than conventional fuels. Ethanol, also called alcohol, is obtained from renewable raw materials.

Easy-Entry – The name says it all: seats with the Easy Entry function provide extra space for easily accessing the rear seats. This is achieved by having a seat that can be slid very far forward and a seat back that can be folded down. The memory function returns the front seats to their previously selected positions, making them even easier to use.

Easy Fold – Easy Fold refers to the easy-to-use folding mechanism for the seats in the second and third rows. This special folding system makes it easy to sink the seats onto the car floor to save space. It eliminates the time and effort needed to remove seats when you want more luggage space.

Emergency Brake Assist EBA – Our Emergency Brake Assist (EBA) System comes to your aid in emergency braking situations. The Brake Assist System senses the force at which you brake to determine where you need full braking power. It then automatically boosts the brake pressure to the ABS control threshold for as long as you keep the brake pedal pressed. If you release the pedal, the system will reduce the brake pressure to match the position of the brake pedal again. This safety function can substantially reduce the distance it takes you to stop.

Electronic Brake-Force Distribution EBD – In cars with front-wheel drive, the front is heavier than the rear. This means that during braking, the car’s center of gravity is displaced forwards. This creates the risk of rear wheel locking due to decreased traction. Electronic Brake-Force Distribution (EBD) uses solenoid valves in the ABS unit to regulate the braking force of the rear wheels and prevent them from locking. The Electronic Brake-Force Distribution function is included in the ABS function. The extent of the EBD application ends where the ABS control takes over.

Elbow Room – Elbow room, as well as head, shoulder and leg room, plays a crucial role in the subjective wellbeing of you and your passengers. Elbow room refers to the distance between passengers, or between the door panel and passenger, at elbow height.

Electric driver seat – A button located at the bottom of the driver seat makes it easy to adjust the height and inclination of your seat.

Electric parking brake – The electric parking brake replaces the traditional manual parking brake. It’s operated by means of two geared electric motors on the rear disc brakes. The mechanical components are designed to hold your parked car securely, even if the onboard electric power supply fails. Indicator lights on the instrument panel and on the dashboard switch, plus an operating sound, tell you when the parking brake has been activated. The easy push-button operation offers more comfort and safety as well. For example, the dynamic automatic brake release makes it unnecessary to manually release the parking brake. All you have to do is drive off, and the brake releases automatically. And because the conventional parking brake lever is no longer necessary, you get more storage space between the front seats. Furthermore, the braking performance is constant at all times and reduces wear resistance. The system is also employed in Hill Hold Control (HHC) and in the emergency braking function, greatly contributing to safety and driving comfort.

Electric mirror adjustment – Interior electric mirror adjustment allows the driver and the front passenger to adjust the exterior mirrors vertically and horizontally until they reach the desired position. Some systems include a memory function so that mirrors accidently misaligned in the car wash are returned to their predetermined positions, for example.

Electric trailer towing device – The electrically-powered, foldable tow bar lets you easily tow a trailer behind your car.

Electric windows – Controls located in the driver’s door let you operate each electric window individually. The front electric windows feature a one-touch open and close function as well as an anti-squeeze function that prevents closing on anything in the way.

Electrochromic interior mirror – Sensitive to dazzling light, dimming the interior mirror to avoid the glare from approaching vehicles.

Electro-hydraulic power steering – Electro-hydraulic power steering is an extension of the well-known hydraulic power steering. The main difference is how the hydraulic pump that supplies the pressure necessary for the power steering is driven. In electro-hydraulic power steering, an electric motor drives the pump, which is controlled according to the required assisting steering force. At very low speeds, or when stationary, the delivery of the hydraulic pump is increased to provide a large amount of steering power. At high speeds, the pump rotational speed is lowered because assistance is not necessary. The advantage of electro-hydraulic power steering is the improved comfort: When manoeuvring, steering is light to handle. But at high speeds, steering is firm. This enhances overall fuel economy, as the power uptake adjusts as required.

Electro-mechanical power steering – Electro-mechanical power steering is a speed-dependent, electrically-controlled assisted steering system that only works when needed by the driver and doesn’t require any hydraulic components. Its advantage over hydraulic power steering is that it consumes less fuel and provides new comfort and safety functions. For example, the active return of steering to the middle position improves the centre feel, and the crosswind compensation takes the weight off the driver when the roadway inclines to one side or a constant crosswind is present. Furthermore, the degree of steering assistance can be individually adjusted depending on the engine and equipment, resulting in a unique steering sensation. These additional functions are made possible by the integration of the control unit into the CAN data bus.

Electronic accelerator – In the conventional gas or accelerator pedal, a mechanical connection (Bowden cables, coupling rod) transmits the accelerator command to the throttle body. The electronic accelerator pedal sends an electronic pulse to the engine control unit, which perfectly coordinates the fuel injection and engine control.

Electronic damper control – In an air suspension system, electronic damper control is the continuous, map-controlled adjustment of the damper settings. It provides extra ride comfort, driving pleasure and safety, plus improved handling when driving over loose surfaces or on off-road terrain. The electronic control unit calculates the required damper settings based on information from the acceleration sensors at the wheels and on the body. It then adjusts the damping to match the car’s speed and the condition of the road surface. In addition, you have the option to manually select the basic setting, the firmer sport setting or the softer comfort setting. Ride height and damping adapt automatically to any load and to all on-road and off-road conditions, resulting in outstanding suspension characteristics and driving safety. The system is able to compensate for any body movements, as well as dampen the pitching vibrations produced when towing a trailer.

Electronic engine management – Electronic engine management coordinates diverse functions in order to achieve maximum efficiency with the lowest possible cost and emissions. These functions include fuel injection, lambda control, exhaust gas recirculation or ignition. The system makes use of several parameters such as rpm, temperature, accelerator pedal position and more.

Emergency Assist – This safety feature provides help in emergency situations. If the Emergency Assist System detects that you seem inactive behind the wheel, it softly brakes twice to alert you. If you fail to respond to the alert, the system will automatically slow and stop your car.

Emissions behaviour – Emissions behaviour describes the property of an engine to control the quality of the exhaust gas during operation. Since the introduction of the EURO 3 Standard, all cars must have an on-board diagnostic feature (EOBD = Euro On-Board Diagnosis). The EOBD monitors all components relevant to emission control, such as the lambda probe or the catalytic converter. If a malfunction occurs, a warning light will appear. Please consult a workshop in this case.

Energy dissipation bumpers – Energy dissipation bumpers are a kind of self-repairing bumper. Up to a speed of 4 km/h, they can prevent damage from little parking bumps. The plastic material of the bumper is designed so that occasional bumps with, for example, bollards or flower pots don’t leave a lasting dent in the bumper, saving you expensive repairs. Clippable protective strips protect the bumper from scratches. They are easy and inexpensive to replace, reducing the cost of maintenance even more.

Energy recovery system – The recovery system recycles the energy normally lost during braking by storing and then using it for acceleration or starting, thus saving fuel and cutting emissions. Recovery is achieved by raising alternator voltage when you slow down and brake. This increases battery charging and helps the car slow down. When you accelerate again, the alternator load is reduced to lighten the burden on the engine and cut your fuel consumption.

Engine Control Unit ECU – Due to complex demands on consumption and exhaust emissions, computer technology has been introduced in engine construction. For instance, Electronic Control Units coordinate the functions of fuel injection and ignition. Sensors detect the respective current state of individual motor functions and forward that information to the control unit. In the engine control unit, the incoming information is processed, corrected if necessary, and passed on as control signals to the individual modules. In order to process the multitude of data, the control unit is equipped with a 16-bit or a 32-bit processor. In the case of a six-cylinder engine running at maximum revolutions, there is an interval of only three milliseconds for changes between two ignitions. In addition, the Engine Control Unit uses the CAN databus to exchange data with the control units of other car systems, such as the ABS / ESP control unit.

Engine Drag Torque Control MSR – Engine Drag Torque Control (MSR) is a function integrated in the Traction Control System (TCS). If the accelerator is released or pressed abruptly on icy roads, the drive wheels may experience slippage. Using sensors in the antilock braking system, the MSR registers the slippage and selectively accelerates to restore stable driving conditions.

Ergonomics – Ergonomics studies the possibilities of and limits to work performance, and how to best adapt working conditions to the needs and comfort of the people in them. In the automotive sector, ergonomics refers to the optimal adaptation of a vehicle to the people inside it. This minimises the strain placed on both driver and passengers. To do this, all possible body sizes, sitting and driving habits need to be taken into consideration. For example, to ensure that the driver can fully devote their attention to traffic, all controls such as switches and levers must be easy to reach, illuminated in the dark and clearly arranged and distributed.

Electronic Stability Control ESC – Electronic Stability Control (ESC) recognises critical driving situations, such as risk of skidding, and systematically prevents the car from doing so. For the ESC to respond to critical situations, the system must constantly receive information. For instance, the system needs to know which way the driver is steering and where the car is moving. The system receives the steering direction from the steering angle sensor and the ABS wheel speed sensors on the wheels. From these two pieces of information, the controller calculates the desired steering direction and the intended driving behaviour of the car. Other important data are the yaw rate and lateral acceleration of the vehicle. Using this information, the control unit calculates the current state of the vehicle. ESC prevents instability of the car when cornering. Instability can occur either while driving at an inappropriate speed, as a result of an unpredictable change in the road surface (wetness, slickness, dirt), or due to an emergency evasive action (the “Elk test”). In this case, it does not matter whether the instability manifests itself by means of understeering (i.e. when the car moves to the outer edge of the bend despite steering at full lock) or by means of oversteering (the rear end breaks away). The computer unit of the ESC detects the type of instability based on the data provided by the sensor technology. It corrects the instability by intervening in the braking system and engine management. In the event of understeering, the ESC decelerates the inside rear wheel. At the same time, the ESC reduces the engine power until the car has stabilised again. ESC prevents oversteering by selectively activating the front brake on the outside of the bend and intervening in the engine and transmission management.

Electronic Wheel-Slip Reduction ESR – By regulating the torque, Electronic Wheel-Slip Reduction (ESR) prevents your wheels from spinning when manoeuvring or accelerating the car in slippery road conditions.

Estate car – An estate car has a longer full height body than that of a hatchback, with a full width door at the rear for easy loading. It’s designed for carrying more luggage.

European New Car Assessment Programme Euro NCAP – The Euro NCAP (New Car Assessment Programme) is a programme to evaluate the passive safety of new cars and is now considered one of the most important benchmarks of passive car safety in Europe. Euro NCAP is organised by the English and the Swedish Transport Authorities, the International Automobile Federation, the FIA, the German ADAC, other European automobile clubs and more. The NCAP test programme simulates four frequent accident situations: an offset frontal collision, a side impact, a pedestrian accident and the so-called pole test. The final evaluation employs a 5-star system for passenger safety (separate for adults and children), and a 4-star system for pedestrian protection.

Exhaust Emission Control System – The exhaust emissions standards for new cars sold in the European Union are defined by legislation adopted by the EU. The standards govern the limits on pollutants emitted in car exhaust gas (sulphur dioxide, nitrogen oxides, hydrocarbons, carbon monoxide, carbon dioxide and diesel exhaust particulates). The more stringent Euro 4 limits became fully effective on January 1, 2007. Euro 5 and Euro 6 limits were introduced in June 2007. New model types may now be approved to the Euro 5 standard. This is compulsory for all new cars after January 2011. A representative unit from each model type is tested, either by independent test organisations, or by the manufacturers or importers themselves at their own test facilities. The results have to be verified by the DfT.

Exhaust gas recirculation – Exhaust gas recirculation is the process of feeding exhaust gas back into the combustion chamber in a carefully regulated way. The recirculation is an effective method of reducing the nitrogen oxide levels at the combustion stage. When the fuel/air mixture burns, the formation of nitrogen oxides increases at a disproportionately high rate as the temperature rises. Recirculating a portion of the exhaust gas back to the chamber lowers the combustion temperature inside the cylinder, reducing the rate of NOx formation. The exhaust gas is directed through a system of pipes back into the intake tract by means of a valve controlled electronically by the engine management unit. From the intake tract, the exhaust gas is drawn back into the combustion chamber.

Exhaust system – The exhaust system is used for removing and cleaning the gases formed during combustion in the engine cylinders.

Five-Valve Technology – An engine’s performance depends on the amount of fuel that can be effectively combusted in the cylinder. A direct gauge of this performance is the volume of air that can reach the cylinders. In this context, five-valve technology offers crucial advantages: engines with five valves per cylinder can be supplied with air better and faster. This boosts torque and power output, as well as improves fuel consumption and emission levels.

Fog lights – Fog lights are medium intensity lights designed to improve your visibility in adverse weather conditions. Usually mounted below your car’s front bumper, the lens and reflector assembly are engineered to direct a wide, low beam of light onto the road and roadsides. The fog lights are designed to reduce the amount of light reflected from fog, rain and snow. They come equipped with a cornering function that illuminates the left or right fog light that is linked to the direction of travel.

Fording depth – This is the depth of water that a car can pass through without taking on water. It’s measured as the distance between the point touched by the car’s tyres and the engine’s air intake system.

Four-link suspension – The four-link suspension is different from other types of designs due to the independent operation of the control and suspension elements. Using four-link front suspension, the structure of the car is indirectly supported by the strut mounted on the support arm. The wheel is guided by four rod-shaped wishbones and a track rod. This structural principle improves steering behaviour and minimises the effects of road bumps on steering. For the rear axle, four-link suspension can be designed very compactly. This allows for longer displacement that is compatible with all-wheel drive. Moreover, the four-link rear suspension works as a lane-corrector in the border area.

Four-Wheel Drive (4 Drive) – Four-wheel drive (4WD), also known as 4×4, refers to a vehicle’s drivetrain that delivers power to all four wheels, enhancing traction and handling, particularly in challenging off-road conditions.

Front and rear parking sensors – The Front and Rear Parking Sensor makes it possible to manoeuvre cars into tight parking spaces without problems. Even with modern cars, it is difficult to estimate the dimensions due to their aerodynamic shape. The parking assistant consists of several ultrasonic sensors, which are integrated in the rear and also in the front, depending on the model. The sensors receive and send impulses in the range of 40,000 Hz. When the impulse reaches an obstacle, it is reflected. The sensor registers the echo. The electronic evaluation calculates, taking into account the time difference between sending and receiving, the distance between the obstacle and the car. If the distance decreases under a certain degree, the driver will be informed of this dangerous short distance by a warning signal.

Front Assist – Front Assist is a radar system that detects situations where the distance to the car in front is critical and helps to reduce your car’s stopping distance when needed. The system also warns you of a dangerous situation with visual and sound signals and with a braking jolt.

Front assist + City Emergency Braking – The Front Assist system stop the car if the distance between your car and the one in front is drastically reduced. If there’s no reaction from the driver, the system will slow the vehicle down to keep a safe distance. Combined with the city emergency braking function, the car will stop completely to avoid a direct collision.

Front Fog lights with Cornering function – The fog lights provide an additional illumination when cornering. When you turn the steering wheel or indicate, the front fog light lights the area you’re turning into As a result, you get a better view of potential hazards, faster. They also alert other road users.

Front Passenger Airbag Deactivation – Deactivating the passenger airbag allows a child seat to be placed in the front passenger seat. Also, when transporting long objects on the passenger side, the airbag should be disabled. This improves practicality and utility. A clear warning signal ensures that the driver is aware of deactivation, thus ensuring safety.

Front-Wheel Drive – Front-wheel drive is the most commonly used drive principle on passenger car models up to the mid-size class. Power is transmitted via the front wheels. The engine, transmission, axle drive and differential are grouped together to form a compact unit. With front-wheel drive, the car is pulled along, so that the drive forces and the inertial force of the car are balanced. The front wheels have to absorb drive, brake and cornering forces. Influences on the steering are counteracted by appropriate front suspension configurations.

Fuel Stratified Injection FSI – refers to petrol engines with direct fuel injection. In direct fuel injection, the fuel is injected directly into the combustion chamber at a maximum pressure of up to 150 bar. The special geometry of the combustion chamber ensures optimum turbulence of the fuel-air mixture. Due to its innovative engine technology, the FSI engine is characterised by high efficiency and above-average efficiency. By adapting driving styles, fuel savings are up to 25 per cent greater compared to engines of the same power using conventional injection technology.

Fuel Cut-Off – The feed flow of fuel is cut off by means of electrical shut-off valves in the event of failure of the system, eg: because of an accident. Thus the risk of fire in the car is avoided.

Fuel Injection System – In petrol engines in modern cars, injection systems take care of preparing the fuel mixture.
When using a controlled catalytic converter, a precisely metered, variable distribution of the fuel is imperative. This requirement can only be optimally met by electronically-controlled fuel injection. The central injection system meters the fuel via an injection nozzle to all cylinders. However, multipoint injection is more efficient and economical. With this system, there is one injector to meter the fuel for each cylinder. The mixture formation (carburation) is usually carried out immediately before the injection valve in the intake manifold. The electronically-controlled fuel injection provides for the formation of the ideal mixture in each cylinder. This achieves high engine performance, low fuel consumption and good exhaust characteristics.

Full LED + Welcome Light – Fully equipped with the latest lighting technology and electronic adjustment, this saves energy and casts a powerful beam. What’s more, the Welcome Light projects the car silhouette on the ground to ensure you can always find your way in the dark.

Full Link Technology – Use Full Link Technology alongside MirrorLinkTM, Apple CarPlayTM and Android AutoTM to seamlessly control your Android or iOS smartphone straight from your intuitive Modular Infotainment Board (MIB). With MirrorLinkTM Technology your smartphone’s screen is mirrored on your navigator, making calling, texting or streaming music a fully integrated experience.

Fuels – Fuels for internal combustion engines are divided into petrol and diesel fuels. Generally speaking, fuels are produced by the distillation of petroleum. For use in motor cars, they must be as pure as possible and free of solid impurities. Petrol is available with different specific gravities and with different octane levels (regular, super, super plus). The octane number indicates the antiknock value. The higher the octane rating, the higher the resistance to knocking. Diesel fuel is produced during distillation of petroleum at 180 to 300°C as what is known as “gas oil”. The quality and properties of petrol and diesel are mainly determined by additives. These chemical additives ensure storage stability, further increased knock resistance and corrosion protection. They improve the flowability of diesel at temperatures below freezing or prevent the formation of ice crystals on the throttle valve which can arise if heat is extracted from the air when the fuel is vaporized. Using catalytic converters makes use of unleaded fuel compulsory. Since organic lead compounds were previously considered the most effective anti-knock agents, lead-free fuel must be enriched with special, high-quality, high-octane, non-leaded components.

Guarantee – A guarantee in the automotive world is a promise from the manufacturer or seller that the car will operate as expected without manufacturing faults. If a problem covered by the guarantee occurs during a set time frame or mileage limit, any necessary repairs are taken care of, often at no extra cost to you. This assurance gives buyers peace of mind by protecting them from unexpected repair expenses due to defects. Checking the specific terms of any guarantee is important so you know exactly what is covered and for how long.

Galvanisation – Galvanising is the most reliable method of protecting sheet steel against corrosion. Galvanisation is a form of zinc-plating in which the zinc reacts with the underlying steel to create a stable compound that is immune to surface damage. Galvanisation is applied in layers of less than 20 micrometres, and is used primarily to treat finer surfaces like the visible surfaces of a car’s body.

Galvanised body – Galvanising is a surface coating of metallic zinc on steel. The zinc forms a physical and electro-chemical barrier to rust. Even if scratched down to the base metal, the zinc layer will continue to protect the steel from rust. Sheet steel can be galvanised on one or both sides.

General Operating License – The General Operating License is mandatory in order to register a car and take it out on the road. The official document required for the General Operating License is the car registration document. In this document, among other things, information about engine cubic capacity, power, emissions classification, seats, key number or trailer loads are included, as well as modifications to the car with the official approval of an inspection body like TÜV or Dekra, (wide tyres, body panels, etc.). If substantial changes are made to a car which the owner does not have entered in the registration document, the General Operating License becomes invalid.

Global Positioning System GPS – Global Positioning System (GPS) is a navigation technology that uses satellites to pinpoint your location anywhere on Earth. It’s the system in your car that helps you get turn-by-turn directions, making travel easier and more efficient.

Gradability – A car’s gradability is its ability to climb slopes. Gradability is measured either in degrees or percentage. A 45 degrees gradient is equivalent to 100 per cent. Gradability is dependent on engine power, drivetrain type, gear ratio, weight, weight distribution, car’s centre of gravity and traction.

Global System for Mobile Communications GSM – GSM stands for Global System for Mobile Communications. The GSM standard has been developed by a working group of European telecommunications institutions. This international standard applies to digital radio networks, such as the D networks in Germany.

Haldex clutch – The Haldex clutch is a component in many all-wheel drive (AWD) systems. It uses a clutch pack that automatically sends power to the rear wheels when the front wheels start to slip—like during rain, snow, or on slippery roads. This helps the vehicle gain extra traction without always running the rear wheels, keeping things efficient and stable. In simple terms, the system smartly balances power between the front and rear wheels based on driving conditions, offering a smoother, safer ride when extra grip is needed. If you’re curious, this technology is commonly found in vehicles from brands like Volkswagen and Land Rover.

Haldex Coupling – The Haldex coupling on our 4DRIVE permanent four-wheel drive system enables the driving power to be distributed variably between the front and rear wheels. It also ensures the effectiveness of electronic systems such as the anti-lock braking system, traction control or electronic differential lock. To achieve this, additional information is taken into account via a computer. Its control system balances not just traction and the resulting differences in speed between the wheels, but also further variables such as handling conditions and drive torque. This enables better interaction with the electronic systems and improves the distribution of driving power with regard to directional stability and safety. The computer uses data from the wheel speed sensors and engine management to react in the best way to the situation.

Hands free electric Boot – Thanks to a Virtual Pedal, a sensor underneath the rear of the vehicle, the boot can be opened hands free, just with a foot movement, and also comes with KESSY. Electrically powered for ease of access to the rear of the vehicle.

Hatchback – A car with a door across the full width at the rear that opens upwards to provide easy access for loading.

Hydraulic Brake Assist System HBA – The hydraulic brake assist helps the driver in the event of emergency or panic braking. The brake assist recognizes from the operating speed of the brake pedal whether the driver wants an emergency stop and increases the brake pressure automatically up to the ABS control range, as long as the driver keeps the pedal pressed. With decreasing brake pressure actuated by the driver, the system reduces brake pressure again to the normal value. Using a sensor, the system detects the rapid pressure increase when actuating the pedal and intervenes to regulate braking. As a result, the stopping distance can be shortened by up to 25%.

Headlight Washer System – The headlight washer system has an electrically driven rotary pump that sprays water or cleaning fluid at high pressure onto your headlight glass from the outside. This means safer driving in rain, snow and muddy road conditions. We have also developed a new headlight washer system, which cleans the clear glass lenses in two stages. When the washer nozzles are extended, the first cleaning stage loosens the dirt. The second stage then rinses off the loosened dirt. The Headlight Washer System is mandatory with xenon headlamps.

Head-Protection Airbag System – In a side impact, the second most common type of accident after head-on collisions, side and head airbags come into play. Head airbags in particular reduce the risk of head injuries and supplement the action of side airbags. Head airbags, also known as window bags, are located along the roof. The head airbag is a flat airbag that when unfolded covers the area of the side windows from the A to the C pillar, thus offering additional, special protection for the head.

Head restraints adjustable to height – Headrests serve not only for seating comfort but are a crucial safety feature. On the one hand, they absorb the backwards centrifugal movement of the head in a frontal accident; on the other hand they prevent the “whiplash effect” in a rear impact. They thus counteract the danger of neck injuries. Maximum protection is only ensured if the head restraints are properly adjusted. That means, the upper edge needs to be adjusted approximately level with the top of the head.

Headroom – Headroom is the distance between the headliner of the car and the crown of the occupant’s head. Sufficiently large headroom is one of the most important criteria for good seating comfort and relaxed driving in a car. Standardized body measurements are used when calculating the headroom.

Heated Front Seats – Heated front seats not only offer luxurious comfort, relaxation and benefits for physical health, but also increase safety. Heating seats and backrests ensures a high level of well-being and prevents a cramped posture. Winter clothes limiting freedom of movement can be dispensed with. This also results in better operation of the restraint system by reducing the slack in safety belts.

Heated Front Windscreen – Annoying and time-wasting scraping of the windscreen in winter becomes unnecessary by using a heatable windscreen. Fine heating wires are embedded in the windscreen which do not restrict the driver’s view in any way. This comfort and safety feature is especially important in the large, high windscreens of vans which are often difficult to reach.

Heat-insulating Glazing – The heat-insulating glazing reduces and delays the heating of the interior space through solar radiation. The best absorption is possible with the corresponding glass tinting. For more protection against heat and blinding, the windscreens are heavily tinted in the upper part.

Hydraulic clutch mechanism – To transmit the pedal movement, a hydraulic clutch mechanism uses a hydraulic line instead of a mechanical connection (eg: a Bowden cable). A piston on the master cylinder at the pedal transmits the pressure through a fluid to the piston of the slave cylinder at the clutch operation on the transmission. Using the hydraulic clutch mechanism, clutch wear is automatically compensated for.

Hydraulic engine mount – Hydraulic engine mounts are intended to prevent vibrations, noise and movements of the engine being transmitted to the body at load changes. Minimised vibration and motor running noise in the interior ensure a higher degree of comfort for the occupants and reduce the stress on the driver.

Hydraulic power steering – To facilitate the work of steering, many cars nowadays are equipped with power steering. This is a hydraulic system consisting of a pump driven by the engine, an oil reservoir and associated pressure lines.

Hydraulic valve lifter – For efficient, economical and durable running of an engine, it is imperative that the valve control ensures an unchanged valve lift over the long term. Valve control using cam followers or rockers with hydraulic compensation elements ensures automatic valve play compensation which is maintenance-free throughout the engine’s life. Thus engine life is extended and servicing and maintenance costs lowered.

Hill Descent Assist – Hill descent assist lets you negotiate extremely steep drops simply and safely. Your car’s speed is maintained at a constant crawling pace without you having to do anything.

Hill Hold Control HHC – HHC (Hill Hold Control) makes moving off on hills an easy matter. As a subfunction of the ESP, the hill hold control records and stores the brake pressure, holds the car stationary on the slope and enables moving off without using the hand brake. Rolling backwards is prevented for about two seconds after the brake has been released.

Hinged Gas Pedal – The hinged gas pedal represents not only an improvement in terms of ergonomics and comfort. It also allows the driver to have better control and thus even more responsive driving.

Humidity Sensor – A special sensor system reduces misting-up of the windows and enhances comfort by managing the humidity levels inside your car. From the data delivered by the humidity and temperature sensor in the base of the interior mirror, the climate control unit calculates the dew point temperature of the air – that is, the temperature at which the air humidity would condense and cause misting. An infrared sensor remotely measures the radiated heat on the windscreen, and calculates the window temperature. To prevent the windows from misting up, the automatic air conditioning system regulates the air humidity.

Independent suspension – Independent suspension provides handling, control and ride benefits. Since each wheel is able to pivot and be suspended separately from all other wheels, it helps create a smooth ride.

Induction System – The components of an engine involved in delivering fuel and air into the combustion chamber. The system includes the fuel injectors, the intake manifold, the throttle body and the air metering device (on petrol engines), intake valves and the air filter assembly.

Infrared Reflective Glass – Normal glass can only reflect UV rays, leaving infrared light (heat radiation) to pass through virtually unhindered. We use a special coating, based on a silver alloy, on our Infrared Reflective Glass which reflects much of the long-wave infrared light. This reduces the heat felt if strong sunlight is shining into the car.

In-line engine – In an in-line engine, as the name implies, the cylinders are arranged in a row, one behind the other, or horizontally, side by side. With few exceptions, in-line engines are limited to five or fewer cylinders. Although straight-six cylinder engines have excellent running performance, they make the body very long which restricts their use and excludes entirely installing them transversely with front-wheel drive. For more than six cylinders, construction in the shape of a V has prevailed. Besides in-line and V-type engines, boxer engines eke out an exotic existence because of their high construction costs.

Immobiliser – The immobiliser is part of the anti-theft device. The engine control unit blocks the ignition and the fuel system. The engine can only be started when the ignition key is used with individually coded chip (transponder).

Integrated child seat – An integrated child seat is a car seat built directly into the vehicle. It can quickly convert into a child safety seat, so you don’t need to bring an extra seat along. This design provides convenience and saves space, making it easier for families on the go. While many appreciate its ease of use and built-in safety, some parents note that because it’s a fixed feature, it might offer less placement flexibility compared to removable seats. If you’re interested in how these systems compare with traditional child seats or want to know more about safety standards, there’s plenty to explore about evolving car seat technology.

Intercooling – In exhaust-gas turbocharging, compression increases the temperature of the fresh air in the charger. Since heated air occupies a larger space than cool air, the cylinders fill with less air than would correspond to the boost pressure and in petrol engines the tendency to knock increases. For this reason, the compressed air is cooled by the engine’s cooling water or the outside air. Intercooling reduces the thermal stress on the engine. In addition, the exhaust gas temperature, NOx emissions and fuel consumption are reduced.

Interior Ambient Lighting – Ambient lighting bathes the interior of your car in subdued light when it gets dark. Concealed LEDs illuminate areas such as doors, footwells and the decorative inserts in the door panels. When driving at night, the glare-free light also helps you locate the controls more easily.

iPod & MP3 Connections – You can play your choice of music from your own external audio device, via your car’s sound system. The USB AUX in port offers you a fast and easy link to files on your MP3 player, iPod and USB memory stick. It’s easy to connect a compatible device to the sound system via a universal port, using a suitable adapter cable for USB or compatible Apple iPod dock connector. Folders and menus can be navigated via the car’s sound system, with the track playing shown on the radio or radio-navigation display. The port also charges your device with a 5-volt charging current.

Isofix – Isofix is the result of the efforts of well-known car makers to create a uniform and optimal standard for anchoring child seats. Isofix is not an official DIN standard. Isofix child seats are equipped with a simplified fastening device. They can be used in all cars which are already factory-equipped with standardised snap couplings. The child seat preinstallation has two bars which are firmly attached to the car body. Isofix-type child seats are firmly attached by two connectors. Isofix child seats can be fitted easily and offer the highest degree of safety due to being robustly attached to the car body.

Jack & Jack Stands – A jack is an essential mechanical device used to lift a vehicle when changing a tire or performing routine maintenance. Once the car is lifted, jack stands serve as safety supports to keep it elevated securely. These tools are indispensable for anyone working on their car and form a core part of automotive safety practices.

Jumper Cables – Jumper cables are the cords used to connect a dead battery to a working one, enabling the car to start again. They are a common fixture in emergency road-side kits and are foundational in tackling battery-related issues on the go.

Jalopy – In a more colloquial context, this term refers to an old, dilapidated car. This term has a nostalgic, sometimes humorous ring to it and is often used in vintage car circles or casual conversation about beat-up vehicles.

JDM – Standing for Japanese Domestic Market. JDM is used to denote vehicles or parts originally built for Japan’s specific market. Over time, JDM cars have earned a passionate following globally due to their performance, reliability, and unique styling cues.

J-turn – Also known as a bootleg turn, a J-turn is a stunt-driving maneuver where a driver rapidly turns the car 180 degrees, often by driving in reverse before snapping the steering to complete the move. This impressive technique is a favorite in action-driving demonstrations and movies

Kessy – A colloquial term often referring to keyless entry systems that let you unlock and start your car without a physical key.

Keyless Entry – A system used to lock and unlock your car remotely, making it more convenient to access your vehicle without using a traditional key.

Kickdown Cable – Found on some automatic transmissions, this cable triggers a downshift when you push the accelerator pedal all the way down, giving you an extra burst of power.

Kill Switch – An emergency switch designed to shut off the engine quickly if needed.

Knee Airbag – A safety feature that deploys in a collision to help protect your knees and legs, working in conjunction with other airbags.

Knock Sensor – This sensor detects abnormal knocking or pinging sounds in the engine and signals the engine computer to adjust the performance parameters, helping to prevent potential damage.

Knuckle (or Knuckle Assembly) – A critical component of the steering system that connects the wheel to the suspension, allowing for smooth steering movements.

Lambda Control – The flawless functioning of a three-way catalyser requires a certain air-fuel mixture: ideally all components are completely burned when 14.7 parts of air are mixed with one part of fuel. In this case, lambda is equal to one. The Greek letter lambda stands for the so-called “air ratio”. Only when lambda = 1 can the catalyser optimally fulfill its task of cleaning the exhaust gas. The lambda control forms a closed control loop in which the lambda sensor, working as a measuring sensor in the exhaust flow, measures the exhaust gas composition. In the event of deviations, regulation via the electronic engine management system ensures that the injection system meters the fuel quantity differently in relation to the proportion of air.

Lane Assist – Lane Assist is a safety feature in many modern cars. It uses sensors and cameras to detect the lane markings on the road. If the car starts to drift out of its lane without the driver signaling, Lane Assist can gently steer the vehicle back on track. It doesn’t take full control of the car, but it provides extra help to keep you safe on the road.

Laser Welding Technique – In the automotive industry, laser welding is acquiring more and more importance. The ability of the laser to bundle light energy to form the finest beams which can even weld metals opens up new possibilities in terms of body quality and stability because weld seams can be made extremely narrow and precise. The very powerful, focused light of laser welding produces very high temperatures which melt the material at a focal point of around 0.5 to 1 millimetre in diameter. Because of the narrow working area, laser welding technology is particularly suitable for butt welding sheets. The advantages are to be found in the higher strength of the joint and new opportunities for design.

Lateral acceleration – Lateral acceleration acts transversely to the direction of travel of a car. It is noticeable, for instance, when driving through a bend as a centrifugal force towards the outside of the bend.

Lateral Gradient – Lateral gradient refers to the sideways inclination angle of the car when driving across a slope.

Leaving-Home Function – The Leaving-Home Function is a convenient car feature that automatically turns on certain exterior lights when you unlock your vehicle with your remote control. It typically activates lights such as the dipped beams, tail lights, and license plate light, making it easier and safer for you to locate and enter your car in low-light conditions, like during the night or on a dark winter morning. This simple automation not only adds a touch of modern convenience but also enhances your safety when leaving your car.

Light Emitting Diode LED – The LED (Light Emitting Diode) is a light-emitting semiconductor having a much longer life and lower power consumption compared to conventional incandescent lamps. The advantages of LED technology compared to conventional incandescent lamps are in their lower power consumption, faster response times, reduced space requirement and a longer service life (the life of the car). LEDs are used, for example, to illuminate the warning indicators (icons) on the instrument panel.

LED Illumination – LED light is produced by means of semiconductor diodes which have lower energy consumption and at the same time a longer service life than conventional bulbs. Thanks to this high level of reliability, their extremely good response times and their small space requirements, LEDs (Light Emitting Diodes) are particularly suitable for use in the front and rear lights or the side indicators in the exterior mirror housings.

LED Interior Illumination + Advanced (multicolour) Ambient Light – This feature adds stylish lighting inside the car, using LED lights to create a cozy and modern atmosphere. The “Advanced (multicolour) Ambient Light” lets you customize colors, so you can set the mood to match your vibe-whether it’s cool blue for relaxation or fiery red for energy. It’s all about making your car feel more inviting and personal.

Lighting – In darkness or difficult lighting conditions headlights serve to illuminate the surrounding area. All lighting equipment on the exterior of a car requires technical approval. The most used headlight is the dipped beam. Full-beam headlights increase the illuminated area in the dark and where traffic density is low. Besides these, the only approved additional lights are fog lights. These may be switched on only in bad weather, for instance in fog, rain or snowfall. On the other hand, rear fog lamps may only be operated when visibility is less than 50 m. Technically speaking, the reversing lamps for passenger cars are only tail lamps. Headlights are always arranged in pairs on the car. Indicators at the front, back and sides as well as side lights (parking lights) and lighting for the rear registration plate complete the lighting equipment of a car.

Local Interconnect Network LIN – The Local Interconnect Network (LIN) is an extension of the CAN data bus, exchanging digital data between actuators or sensors and the corresponding control units. One example of LIN bus application is the electric glass sunroof whose servomotor receives its commands from the comfort control unit via the LIN bus. LIN also controls the windscreen wiper and heater motor systems. Commands are only ever transmitted in one direction, from the master control unit to the downstream sensor or actuator, the ‘slave’. The master can transmit commands to up to 16 downstream slaves.

Litre Capacity – Litre Capacity refers to the total volume of all the engine cylinders, measured in litres. It tells you how much air and fuel the engine can draw in during one complete cycle. A larger litre capacity generally means the engine can produce more power, but it also depends on other factors like efficiency and design. Essentially, it’s a quick way to get a sense of the engine’s potential size and strength.

Low Range – Low range is a reduction gear range in off-road cars that makes driving easier on difficult terrains and on steep gradients. Together with 4DRIVE four-wheel drive, it allows the car to make good progress over rugged ground.

Lumbar Support – Lumbar support ensures that the optimal sitting posture is maintained. Especially during long trips, the muscles can sag due to fatigue. Lumbar support counteracts this by relaxing the spine, thus preventing potential complaints as a result of poor posture, cramping or existing back problems.

Maximum Rear Axle Load HVV – is a specification that indicates the maximum weight that can be placed on a vehicle’s rear axle. This includes the weight of the vehicle itself plus any cargo or passengers. Exceeding this limit can affect vehicle handling, braking performance, and tire wear. The HVV rating is determined by the manufacturer based on the vehicle’s suspension, frame, and tire capacity. You’ll find this specification on the vehicle’s data plate or in the owner’s manual.

MacPherson Strut – Refers to a particular form of independent suspension on the front axle of a car. The MacPherson strut takes over the tasks of a steering rod and serves simultaneously for suspension and vibration damping. The advantages of this system are, firstly, the space and weight-saving construction, and secondly, the large spring travel. The connection of the control arm to the subframe is implemented by means of two rubber-metal bearings. By making a functional separation according to longitudinal forces (front bearing) and transverse forces (rear bearing), it is possible to achieve an optimum level of agility, driving safety and comfort without them interfering with each other. In practice, this axle construction is noticeable because of its comfortable ride and high degree of driving safety.

Main-beam assistant – The main-beam assistant provides more comfort and safety when driving at night. The main-beam assistant helps the driver in the dark above speeds of 60 km/h. Oncoming cars and those ahead that are sufficiently illuminated are identified by a camera built into the interior mirror and the system automatically switches between dipped and main beam.

Main injection – In modern diesel engines, the fuel is not always injected at one time into the combustion chamber, but depending on the engine speed and load, the injection is divided into as many as four individual injections. During the main injection, as the name suggests, the main part of the fuel is fed into the cylinder. Before the main injection, the pilot injection takes place; what is known as the post injection terminates the injection process.

Manual Gearbox – A manual gearbox is a type of transmission that requires the driver to change gears manually using a clutch pedal and a gear stick. This gives you more control over the car, letting you decide when to shift gears based on your speed and driving conditions. While it can take a bit of practice at first, many people enjoy the engaging and involved driving experience it offers.

Manual Transmission – A manual transmission is a type of car system where you change the gears yourself using a gear stick and a clutch pedal. It gives you more control over how the car accelerates, which some drivers really enjoy. While it can be more engaging and sometimes more fuel efficient, it also means you need a bit more skill, especially in stop-and-go traffic.

Map Care (Cartography update) – is a service in some vehicles that keeps your navigation maps current. Essentially, your car’s system updates its road and map information twice a year over a three-year period, ensuring that you always have the latest details for a smoother and more reliable journey

Massage Function (seats) – is a feature in many modern cars that adds a massage-style vibration or kneading motion to the seat. This function is designed to help relieve muscle tension and improve comfort during long drives. It works by using built-in motors or air chambers that can target different areas of the back and sometimes even the legs, giving you a more relaxing ride. The settings are often adjustable, so you can choose the intensity and style of the massage to suit your needs.

Misfuel Prevention Device – A Misfuel Prevention Device stops you from putting the wrong fuel in your car. It’s a small part inside your fuel tank opening that only lets the right size nozzle fit. So if you have a diesel car, it blocks gasoline nozzles from going in.

Mobile phone compatibility – Mobile phone compatibility means how well your phone connects to your car. Most cars today can link to your phone through Bluetooth. This lets you make calls hands-free and play music wirelessly. Many cars also work with Apple CarPlay or Android Auto, so you can use your phone’s maps and apps on the car’s screen. Once you pair your phone, it usually connects automatically when you get in the car. You can talk, text, and navigate without picking up your phone. Older cars might only do basic calls through Bluetooth. Newer ones often connect wirelessly – no cables needed.

Mobile Phone Preparation – Telephone preparation uses Bluetooth radio technology to access your mobile phone. The system detects that your mobile phone is present in the car, and receives and uses all its SIM and GSM data. The system transfers all the relevant information to the car system using the remote SIM access profile (RSAP). This means that with just one SIM card all the directories stored in your mobile phone are also available in your car. The connection to the external aerial is made automatically, without you having to take the mobile out of your pocket or operate it.

Mobility Tyres – Mobility tyres are special run-flat tyres that let you keep driving even after getting a puncture. Think of them as your safety net on wheels. When a regular tyre goes flat, you’re stuck on the roadside. But mobility tyres have reinforced sidewalls that support your car’s weight even with no air pressure. You can drive about 50 miles at speeds up to 50 mph to reach a tyre shop or safe location. Most modern cars come with these instead of spare tyres. They save space in your boot and mean you don’t need to change a wheel in dangerous conditions like busy motorways or bad weather. The trade-off is they’re more expensive to replace and give a slightly firmer ride than regular tyres. But for many drivers, the peace of mind is worth it.

Motor Efficiency – Motor efficiency measures how well an engine converts fuel into useful power. Think of it like asking “how much of the gas you put in actually moves your car forward?” A perfectly efficient engine would turn 100% of fuel energy into motion, but real engines waste energy as heat, friction, and noise. Most car engines are only about 25-35% efficient – meaning roughly two-thirds of your fuel just becomes waste heat. Higher efficiency means you get more miles per gallon and better performance from the same amount of fuel. It’s why newer engines with better technology often deliver better fuel economy than older designs.

Miles per gallon MPG – Miles per gallon, or MPG, tells you how far your car can travel using one gallon of fuel. Think of it like measuring how thirsty your car is. If your car gets 30 MPG, that means it can drive 30 miles before using up one full gallon of fuel. A car with higher MPG numbers is more fuel-efficient – it stretches each gallon further, saving you money at the fuel pump. Most cars today get somewhere between 20 to 40 MPG, depending on their size and engine type. Smaller cars usually sip fuel more slowly than big trucks or SUVs, which consume it faster. You calculate MPG by dividing the miles you drove by the gallons of fuel you used. So if you drove 300 miles and used 10 gallons, your car got 30 MPG for that trip.

Modular Transverse Matrix MQB – is a strategy that standardises car components and production processes. It allows the Volkswagen Group to produce models of different brands and models together on the same assembly line.

Multifunction Display – The MFA multi-function display in the driver’s direct field of view provides convenience and safety in one compact information unit. Important car information can be taken in at a glance, allowing the driver to devote his attention to what is happening on the road.

Multifunction Steering Wheel – A multifunction steering wheel has extra buttons and controls built right into it. Instead of reaching for the dashboard or center console, you can control things like your radio, phone calls, cruise control, and voice commands just by pressing buttons on the steering wheel itself. Most modern cars have this feature because it keeps drivers from getting distracted by reaching around the cabin to adjust settings.

Multi-Link Rear Axle – A multi-link rear axle is like having several metal arms connecting your car’s rear wheels to the body instead of just one big solid bar. This setup gives your car better handling because each wheel can respond to bumps and turns more precisely. When you hit a pothole with one rear wheel, it doesn’t shake the whole back end of the car as much. When you’re cornering, the wheels can adjust their angles slightly to grip the road better. You’ll find this system on many modern cars, especially sportier ones and luxury vehicles. It’s more complex and expensive than simpler rear axle designs, but it makes the ride smoother and gives you better control when driving.

Multi-Link Rear Suspension – On multi-link rear suspension, three transverse and one longitudinal link per wheel (four-link principle) each absorb different forces. This means that longitudinal and transverse dynamics can be configured precisely and almost independently of each other, achieving maximum directional stability and comfort. Only small modifications need to be made to the structure of the multi-link rear suspension for it to be suitable for use on front-wheel drive models as well as four-wheel drive cars.

Multi-Purpose Rear-Window Aerial – The multi-purpose rear window aerial combines aerials for remote operation of the central locking, optional auxiliary heating and navigation systems, and the aerial amplifiers for the radio and TV, all in one unit. The various aerials, which offer optimum reception and transmission quality, are integrated into the rear window. Radio stations and TV channels are picked up by an invisible film with a printed aerial conductor. On the upper section of the rear window are the aerials for receiving signals from the radio remote control for operation of the central locking or auxiliary heating.

Multitronic – The Multitronic is an automatic transmission that uses a continuously variable transmission ratio. Transmissions of this type are also called CVT (Continuously Variable Transmission). By means of two variators, each conically shaped, the drive belt (a link chain) can glide infinitely over differing radii on the two axles of the transmission. As it does so, the electronic control continuously monitors and optimizes the transmission ratio. This automatic feedback control of the transmission ratio enables transmission without interrupting traction. The Multitronic always uses the optimum torque and enables ideal acceleration and fuel economy at the same time. A special feature of the Multitronic in conjunction with the Tiptronic is that permanently programmed “virtual” gears can be simulated. In the correspondingly selected mode, this mode allows the driver to shift gear via rocker switches on the steering wheel.

Multi-Valve Technique – Multi-valve technique is when a car engine has more than two valves per cylinder instead of the old standard of just two. Think of valves like doors that let air and fuel in, then let exhaust gases out. Old engines had one intake valve and one exhaust valve per cylinder. But engineers discovered that adding more valves – usually four per cylinder – works much better. With four valves, you get two smaller intake valves and two smaller exhaust valves. This creates more total opening area, so the engine can breathe easier. It’s like having two narrow doorways instead of one wide one – more people can flow through at the same time. The result? Better airflow means more complete fuel burning, which gives you more power and better fuel economy. The engine runs smoother too because everything flows more efficiently. Most modern cars use this four-valve setup now. Some high-performance engines even use five valves per cylinder, but four is the sweet spot for most applications.

Mechanical Parking Aid, Park Assist – The Park Assist can be activated by the driver via a switch on the central console. By activating the indicator stalk, he decides the side on which the stationary traffic is to be scanned. While driving by (up to a speed of 40 km/h and a lateral distance of 0.5 to 1.5 metres), the sensor mechanism detects parking spaces that are large enough to park the car safely. These must be at least 1.1 metres longer than the total length of the car. Once a parking space is detected, a message appears on the multifunction display. Subsequently, the instruction is given to enter the starting position; this is necessary for the parking procedure. The automatic steering control is activated by engaging reverse gear. The driver can take his/her hands off the wheel and only needs to accelerate and brake gently in which he/she is acoustically assisted by the ultrasonic parking aid. The car automatically parks in reverse, perfectly in line. Apart from that, any other parking maneuvers necessary depend on the size of the parking space and are communicated to the driver via the display. The driver can of course intervene at any time in the automatic parking process. The system parks automatically both in parallel parking as well as in parking bays. Unparking from parallel parking spaces is also possible.

Navigation System – A navigation system in your car is like having a smart map that talks to you. It uses GPS satellites to figure out exactly where you are, then shows you the best route to get where you want to go. Think of it as your personal driving assistant. You type in an address or say it out loud, and the system calculates the fastest or shortest path. As you drive, it gives you turn-by-turn directions through a screen and voice commands like “turn left in 500 feet.” Modern systems do more than just directions. They show real-time traffic, suggest alternate routes if there’s a jam, and can even find nearby gas stations or restaurants. Some connect to your phone to stay updated with the latest road information. It’s basically replaced the old paper maps and asking for directions – now your car knows the way and guides you there step by step.

Night-time Design (switches) – Night-time design switches are car controls that light up or glow in the dark so you can find them easily when driving at night. Think of your radio buttons, climate controls, or window switches – they have soft backlighting or illuminated symbols so you don’t have to fumble around or take your eyes off the road to adjust something. It’s basically making sure drivers can see and use important controls without getting distracted, which keeps everyone safer on dark roads.

Noise insulation – is soundproofing material that keeps outside noise from getting into your cabin. Think of it like putting cotton in your ears – it blocks unwanted sounds. Car makers put special foam, rubber mats, and thick materials in your doors, floor, and roof. This stops road noise, wind sounds, and engine rumble from bothering you while driving. Good noise insulation makes your ride quieter and more comfortable. You can actually have a normal conversation without shouting over highway noise.

NOx exhaust treatment system – The catalytic converter selectively converts nitrogen oxide in the exhaust gases into nitrogen and water. To do this, it uses a synthetically produced aqueous urea solution, carried in an auxiliary tank. The substance, containing 32.5 per cent urea, is added continuously to the exhaust tract, upstream of the Selective Catalytic Reduction (SCR) catalytic converter. It is metered according to the mass flow rate of the exhaust gas and is regulated by the engine management system, which receives information from the NOx sensor.

Occupant Cell – An occupant cell is like a protective cage built into your car’s body. Think of it as a strong metal shell that surrounds where you sit. When your car gets hit in a crash, this cell is designed to stay intact and keep its shape. The front and back of your car are meant to crumple and absorb the impact energy, but the occupant cell stays rigid to protect you inside. It’s basically the safe room of your vehicle – the engineers make it extra strong with reinforced steel beams and special construction so that even in a serious accident, the space where you’re sitting doesn’t get crushed. This gives you the best chance of walking away from a crash. Modern cars spend a lot of engineering effort on making this protective cage as strong as possible while keeping the car lightweight for good fuel economy.

Occupant Protection – In the event of an accident, the driver’s feet and lower legs are vulnerable to injury depending on the type and severity of the collision. In order to reduce that risk we make carefully calculated use of deformation elements for the pedals and foot rest. The deformation of the front bulkhead in the Euro NCAP offset crash test, for example, leads to deliberate free movement of the pedals above a defined force level. This disconnects the pedals from the intrusion, so they remain mobile and exercise very little force, reducing the risk of foot and lower leg injuries.

Octane Number – indicates your car fuel’s anti-knock rating and is a measure of the fuel’s ability to resist engine knocking. Knock occurs when the fuel-air mix in the cylinder explodes instead of burning in a controlled way. If fuel has a high octane number, it will have a higher resistance to engine knocking. This is determined according to RON (Research Octane Number) under specific test conditions using precisely defined test engines. Regular Unleaded has the lowest rating at 95 RON, followed by Super Unleaded with 98 RON. The higher the octane number, the higher the self-ignition temperature of petrol and the lower the knock tendency during combustion (self-ignition temperature of regular fuel 450-550 °C, Super fuel 480-700 °C).

Oil – the lifeblood of your engine. Think of it like blood flowing through your body. Engine oil lubricates all the moving metal parts inside your engine so they don’t grind against each other and wear out. Without oil, metal rubs on metal, creates heat, and your engine seizes up in minutes. Oil also carries heat away from hot engine parts and keeps everything clean by picking up dirt and metal particles. Over time, oil breaks down from heat and gets dirty, which is why you need to change it regularly. Fresh oil is smooth and amber-colored, while old oil turns black and thick. Check your oil level with the dipstick when the engine is cool. Low oil means expensive engine damage. Think of oil changes like brushing your teeth – skip them, and you’ll pay for it later.

Oil circuit – The oil circuit of an engine needs to ensure that all moving mechanical parts and all places where friction between engine parts occurs are permanently supplied with a film of oil. In conventional car engines, the oil sump forms the reservoir for the engine oil circulating in the oil circuit. With the engine running, the oil pump ensures uniform oil pressure in the oil circuit. The engine’s oil circuit also has an important task as a coolant in the crankcase.

Oil filter – Dirt particles resulting from combustion and residues contaminate the engine oil and reduce its lubricity. The oil filter integrated into the oil circuit filters out these impurities. In the interests of long engine life, changing the oil and filter at the prescribed intervals is recommended.

On-Board Computer – continuously informs the driver by specific displays on the instrument panel about the current or average fuel consumption. From this information, the on-board computer calculates the range with the fuel remaining in the tank. Additional information about the average speed or travel times can also be called up. With all this information the driver receives important clues about the most efficient and fuel-saving driving style.

One-Touch Function – This is a convenience feature that lets you fully open or close a car window with just a single press of the button, rather than holding it down the entire time. Without one-touch, you press and hold the window button until the glass reaches where you want it. With one-touch function, you tap the button once and the window automatically travels all the way up or down on its own. The system uses a motor controller that remembers the window’s full travel distance. When you tap the button, it sends power to the window motor for that pre-programmed time. Most systems include a safety feature that stops the window if it meets resistance. You’ll typically find this on the driver’s window as standard, though many modern cars include it on all power windows.

Optical Parking Assistant / Optical Parking System OPS – The Optical Parking Assistant assists the driver in addition to the acoustic parking assistant and registers obstacles in front of or behind the car. Within the detection field, the position of obstacles is shown graphically on the display of the sound or media system.

Outside Temperature Display – The outside temperature display increases active safety since the driver can react quickly at temperatures around freezing point and can adapt his driving style to possible hazards caused by snow or black ice. Especially during the cold season, the outside temperature display represents a significant safety feature since the driver is constantly aware whether there is a risk due to low outside temperatures.

Overhead Camshaft – This means the camshaft sits on top of the cylinder head, right above the valves. Instead of being down in the engine block like older designs, it’s mounted up high where it can directly operate the intake and exhaust valves through rocker arms or direct actuation. The camshaft has specially shaped lobes that push the valves open at precisely the right moments as the engine runs. Being overhead reduces the number of parts needed compared to pushrod systems, which means less weight, fewer things to wear out, and more accurate valve timing. You’ll see this setup in most modern engines because it allows for better breathing – the valves can open wider and stay open longer, letting more air and fuel in and exhaust gases out more efficiently. It also makes the engine rev higher and respond quicker since there’s less mechanical complexity between the camshaft and the valves.

Oversteering Driving Behaviour – Oversteering was formerly a typical self-steering response of rear-wheel drive cars. The car shows a tendency to swing with the tail out to the curve outer edge at load changes, hard steering manoeuvres or sudden acceleration. Oversteering can be again compensated through a dosed countersteering, but this requires driving skills.

Oxidation Catalyst – The exhaust gases from diesel engines, since they work with excess air, cannot be treated by a three-way diesel catalytic converter because using a lambda control is excluded on technical grounds. Here, an oxidation catalyst is used to reduce HC and CO to CO2. On the other hand, it is not suitable for reducing nitrogen oxides.

Pedals with Programmed Deformation – a safety feature built into modern cars. Basically, in a front-end crash, these pedals are designed to collapse in a specific way instead of being pushed straight back toward the driver. The pedal assembly folds downward and away, reducing the chance of foot and leg injuries. It’s like having a crumple zone specifically for your pedals. We started adding these to vehicles after seeing too many lower limb injuries in accidents where rigid pedals would trap or crush the driver’s feet. Smart engineering that doesn’t cost much but saves a lot of pain.

Power Steering – A system that makes turning your steering wheel easier by using hydraulic fluid or electric motors to assist your steering effort. Without it, you’d need a lot more muscle to turn the wheel, especially when parking or driving at low speeds. Most modern cars have either hydraulic power steering (uses fluid and a pump) or electric power steering (uses an electric motor). When it fails, your steering becomes heavy and hard to turn, but the car is still drivable.

Power Steering, Electromechanical – This system uses an electric motor to help you turn the steering wheel instead of hydraulic fluid like older cars. The motor kicks in when you need it, making steering easier at low speeds and parking, but firms up at highway speeds for better control. It’s more fuel-efficient than hydraulic systems since the motor only works when you’re actually steering, plus there’s no fluid to leak or change.

Power Steering, Electrohydraulic – This system combines electric and hydraulic components to assist your steering. An electric pump pressurizes hydraulic fluid instead of using a belt-driven pump from the engine. The computer controls when and how much assistance you get based on your driving conditions. It’s more fuel-efficient than traditional hydraulic power steering because the electric pump only runs when you actually need steering help, not constantly like the old belt-driven systems.

Power – Engine power is the rate at which the energy in fuel is converted into mechanical work.

Paddings – The padding built into doors absorbs the impact energy in a side crash and this way is intended to further reduce the risk of injury in the pelvic and rib area. Padding thus belongs with the other measures for the passive safety of a car.

Paint Protection – This is a clear coating applied over your car’s paint to shield it from damage. Think of it like invisible armor that blocks UV rays, bird droppings, tree sap, and minor scratches from hitting your actual paint. There are usually two types: paint protection film (a physical clear wrap) or ceramic coating (a liquid that hardens). Both make your car easier to wash and keep that showroom shine longer. The film is thicker and handles rock chips better, while ceramic coating is cheaper and still gives good protection. Bottom line – it’s an extra layer that takes the beating so your paint doesn’t have to.

Panorama Window Panel – A large glass panel that extends across the roof of a vehicle, typically from front to back. It’s bigger than a standard sunroof and gives passengers an open, airy feeling with more natural light. Most panoramic panels can tilt or slide open for ventilation. They’re made of tempered or laminated glass and include UV protection. Common maintenance issues include seal leaks, motor problems in power units, and occasional glass stress cracks from temperature changes.

Park Assist – A system that helps you park your car automatically or with guidance. Uses sensors and cameras around the vehicle to detect parking spaces and obstacles. Some versions steer for you while you control gas and brake, others do everything automatically. Common types include parallel parking assist and perpendicular parking assist. If it malfunctions, check for dirty sensors or camera lenses first – they’re usually mounted in the bumpers and mirrors.

Parking Heater – Warms engine and vehicle faster in extremely cold weather.

Parking sensors – These are small electronic devices mounted in your car’s bumpers that help you park safely. They use ultrasonic waves to detect objects around your vehicle and warn you with beeping sounds that get faster as you get closer to something. Most cars have them in the rear bumper, but some also have front sensors. When they start acting up, it’s usually because they’re dirty, damaged, or there’s a wiring issue. A quick cleaning often fixes minor problems, but faulty sensors need replacement.

Passenger Safety Cell – The passenger cabin (passenger cell) of a car meets the requirements for a passenger safety cell, so that this structure and thus the survival space of the passengers in severe accidents remain as intact as possible. This requires a design which “deflects” the occurring forces during an accident, that is to say, it occurs in those parts of the bodywork which are designed as programmed deformation zones to reduce these forces.

Passive Safety Features – Passive safety includes all those car features that help to reduce the consequences of an accident for everyone involved. Passive safety features are divided into two areas. Exterior safety: this includes all car-related measures that are appropriate to limit as much as possible injuries to road users involved in the accident outside the car. In model development, the objective is to design bodies with a correspondingly suitable deformation and high energy dissipation. Interior safety: this includes all car measures whose aim is to keep the effects of forces acting on the occupants in an accident as low as possible. In addition to securing devices such as belts, belt tensioners, airbags and headrests, a sufficiently large “residual space” contributes substantially to the interior safety of a car. There are also all the constructive measures that reduce the risk of injury, such as avoiding sharp edges or using soft, yielding materials for linings or the dashboard area.

Pearl Effect Pigments – responsible for the colour and the effect of the paint coating. The colour is determined by pigments made of mineral or organic substances. Plastic pigments, which are coated with titanium oxide or iron oxide, cause the pearl effect. The various shades of colour arise as a result of light refraction and reflection on the coating of the pigments. Depending on the thickness of the oxide layer and the incidence of light, a different play of colours is produced with different pearl effects: reddish, white, purple or golden.

Pedestrian Protection – This is a safety system designed to reduce injuries when a car hits a pedestrian. The car uses sensors to detect impact with a person, then automatically pops up the hood slightly and activates soft bumper zones. This creates more cushioning space and moves hard engine parts further away from the impact zone. Some cars also have external airbags that deploy to soften the blow. It’s basically making the car less deadly if it accidentally hits someone walking.

Petrol Direct Injection – Instead of mixing fuel and air before it enters the cylinder, this system sprays petrol directly into the combustion chamber under high pressure. Think of it like a precision spray gun that delivers fuel exactly where and when it’s needed. This gives better fuel economy, more power, and cleaner emissions compared to older injection systems. The downside? More complex components that can be expensive to fix, and carbon buildup on intake valves since there’s no fuel washing over them anymore.

Piezo Injectors – These are super-fast fuel injectors that use piezoelectric crystals instead of regular electromagnets. When electricity hits the crystal, it expands instantly and opens the injector valve. They’re way quicker than standard injectors – we’re talking microseconds here. You’ll find these mainly in modern diesel engines, especially European cars like BMW, Mercedes, and Audi. They give much better fuel control, which means cleaner emissions and better fuel economy. The downside? They’re expensive to replace and need specialized diagnostic equipment when they go bad. When they fail, you’ll usually see rough idle, poor fuel economy, or black smoke from the exhaust. Not something you can fix in your garage – these need proper dealer-level tools to diagnose and calibrate.

Pyrotechnic Belt Tensioner – This is a small explosive device that instantly tightens your seatbelt during a crash. When the airbag sensors detect an impact, it fires a tiny charge that pulls your belt tight against your body in milliseconds. This keeps you firmly in your seat and properly positioned for the airbag to work effectively. Think of it as a mini rocket that yanks your seatbelt snug the moment trouble starts. It’s a one-time use system that gets replaced after any accident where it activates.

Pitch and Roll of the Bodywork – Pitch and roll means torsional vibrations about the transverse axis of a car, for example when moving off (spring extension at the front – spring compression at the rear). These body movements occur when the suspension of the car is not sufficiently damped. Only optimal matching of suspension and damping is the basis for excellent ride comfort while giving driving safety.

Plastics – These are the interior and exterior trim pieces made from various plastic materials. Think dashboard panels, door handles, bumper covers, and interior trim. Over time, they can fade, crack, or break from sun exposure and wear. We often need to replace or repair these components during bodywork or interior restoration. Different types require specific adhesives, paints, or welding techniques depending on the plastic type – ABS, polypropylene, or urethane.

Pollen filter – Also called cabin air filter. It’s a rectangular filter that sits in your car’s ventilation system, usually behind the glove box or under the hood. Catches pollen, dust, and other particles before air enters your cabin through the vents. Gets dirty over time and blocks airflow. Replace it every 12,000-15,000 km or when your AC/heat feels weak. Simple swap – no tools needed on most cars. Clean air means better breathing and cleaner interior.

Post-injection – A secondary fuel injection that happens after the main combustion event. This extra shot of fuel into the cylinder helps burn off soot particles in the exhaust system, keeping your diesel particulate filter clean. Without it, your DPF would clog up fast and cause engine problems.

Power Operated Tailgate – This is an electric system that opens and closes your vehicle’s rear door or tailgate automatically. Instead of manually lifting the heavy tailgate, you press a button on your key fob, dashboard, or the tailgate itself. Electric motors and hydraulic struts do the work for you. Most systems also have sensors to stop the tailgate if it hits something while closing. It’s especially helpful when your hands are full with groceries or cargo.

Powertrain – This is everything that makes your car move forward. It includes your engine (where power starts), transmission (changes gears), driveshaft, and axles. Think of it as the complete system that takes fuel, turns it into power, and delivers that power to your wheels.

Power Weight Ratio – This tells you how much horsepower your car has for every pound it weighs. You calculate it by dividing the engine’s horsepower by the car’s total weight. A higher ratio means better acceleration and performance. For example, a 300hp car weighing 3,000 pounds has a ratio of 0.10 hp per pound, while a 400hp car weighing 4,000 pounds also has 0.10 – they’ll accelerate similarly despite the power difference. Sports cars aim for high ratios by adding power or reducing weight. That’s why a lightweight motorcycle can outrun a heavy truck even with less horsepower. It’s one of the key numbers we look at when predicting how quick a vehicle will feel on the road.

Pre Crash Sensors – In the event of an accident, intelligent sensors are designed to trigger off restraint systems for you and your passengers at the right moment. At the heart of this system is the airbag control unit which decides whether restraint systems should be deployed and ignites the airbags and belt tensioners accordingly. Two remote sensors allow the system to determine the pattern and severity of a head-on collision very quickly. These sensors, which measure acceleration, are located in your car’s front impact-absorbing zone. They supply signals to the control unit. The rate of deceleration as measured in the central control unit is used as a further source of information for determining the severity of the impact.

Pre-injection – The pre-injection (also called pilot injection) is performed before the main injection. Thereby, the combustion process should be “gentle” designed in diesel engines. Smoothness and noises should be improved.

Programmable interval of the windscreen wiper – This lets you adjust how often your wipers sweep when they’re on intermittent mode. Instead of fixed timing, you can set them to wipe every few seconds or wait longer between sweeps, depending on how much rain you’re dealing with. Most cars have a dial or button that adjusts the delay from fast intervals to slow ones. It’s basically giving you control over the pause time between wiper cycles.

Programmed Deformation Zones – These are specific areas of your car designed to crush in a controlled way during a crash. Think of them as built-in weak spots that absorb impact energy by folding up like an accordion. The front and rear of your vehicle have these zones, while the passenger compartment stays rigid. It’s like having a buffer that sacrifices itself to protect you – the car gets totaled, but you walk away. Modern cars are engineered to fail in the right places at the right time.

Progressive Steering – This means the steering wheel becomes less sensitive as you turn it more. When you make small adjustments, like staying in your lane, the car responds gently. But when you need to make sharp turns, like parking or tight corners, you have to turn the wheel more to get the same response. It’s like having light steering for highway driving and heavier steering for precise maneuvering. This system uses variable gear ratios in the steering rack to give you better control at different speeds and turning angles.

Protection Against Corrosion – This is how we keep your car’s metal parts from rusting and rotting away. We use special coatings, galvanized steel, and rust-proofing treatments to stop moisture, salt, and oxygen from eating through the metal. Without this protection, your car’s frame, body panels, and exhaust system would turn into Swiss cheese pretty fast, especially in areas with winter road salt or coastal humidity. Think of it like sunscreen for your car’s metal – it creates a barrier that blocks the bad stuff from getting through.

Pump / injector technology – This is where the fuel pump and injector are combined into one unit, instead of being separate components. Each cylinder gets its own pump-injector that sits right on top of it. When activated, it pressurizes the fuel to extremely high levels and injects it directly into the combustion chamber. This setup gives you better fuel atomization, more precise timing control, and higher injection pressures than conventional systems. You’ll mainly see this in diesel engines, especially heavy-duty applications. The downside is they’re more expensive to replace when they fail, but they deliver superior performance and fuel efficiency.

Quattro – All-wheel drive system made by Audi. Power goes to all four wheels instead of just front or rear. Gives better grip in snow and rain. Uses center differential to split power between front and rear axles.

Quarter Panel – Metal body piece behind rear doors on each side of car. Gets damaged a lot in parking lot dings and side crashes. Usually needs bodywork or replacement when dented badly.

Quick Release – Fast disconnect system for parts like steering wheels or battery terminals. Race cars use these so drivers can get out fast in emergencies. Some aftermarket wheels have quick release hubs.

Quench Area – Tight space between piston top and cylinder head when piston is at top. Cools down fuel mixture to prevent knocking. Bad quench design causes engine ping and reduced power.

Rack and Pinion Steering – The simple and maintenance-free design together with the high reliability and extremely low wear has provided the wide diffusion of the rack and pinion steering. A pinion transmits the movement of the steering wheel to the rack and moves it laterally. A play between the components is automatically compensated.

Radio remote control – A wireless system that uses radio frequency signals to operate your car’s functions from a distance. Most commonly found in key fobs for locking/unlocking doors and starting the engine. The fob transmits a coded radio signal to a receiver module in your vehicle. When the correct code matches, it activates the requested function like door locks or remote start. Uses short-range radio waves, typically around 315MHz or 433MHz frequency. If your remote stops working, it’s usually a dead battery in the fob or interference blocking the signal.

Rain sensor – A small electronic device mounted on your windshield that automatically detects water droplets. When it senses rain, it triggers your wipers to start without you touching anything. The sensor uses light beams that get disrupted when raindrops hit the glass. More rain means faster wiper speed, less rain means slower wiping. If it stops working, your wipers won’t auto-start and you’ll need to operate them manually using the wiper controls.

Ramp Angle – The ramp angle is the maximum angle at which the car can travel at low speed over a ramp or obstacle without the underbody touching the edge of the ramp.

Rear cross traffic alert – It makes rear-parking manoeuvres easier, as it stops the car if other vehicles or obstacles are crossing, even if the driver can’t see them.

Rear view camera – A small camera mounted on the back of your vehicle that shows what’s behind you on a dashboard screen when you shift into reverse. It helps you see obstacles, people, or other cars that might be in your blind spots while backing up. The camera automatically activates when you put the car in reverse gear and usually has guide lines on the screen to help you judge distance and steering angles. It’s now required by law on all new cars to improve safety and prevent backup accidents.

Rear view mirror, autodimming – The auto-dimming rear view mirror offers greater safety when driving at night, as it stops you from being dazzled by traffic travelling behind. It consists of a mirror element and an electronic system that detects light from in front and behind by means of photo sensors. If the amount of light from behind is greater than that in front, the mirror is darkened. The surface of the mirror features a layer of electrolytes, similar to the LCD display of a mobile phone. The electrolytes consist of uniform crystals. When a voltage is applied, the crystals arrange themselves at a given angle, determining how much light is reflected. The strength of the voltage determines to what extent the mirror is darkened.

Recycling – A car is composed for the most part of valuable materials of which nowadays a high percentage is recovered at the end of a long car service life and recycled.

Recovery of braking energy – This is when your car captures the energy that normally gets wasted as heat when you brake. Instead of just throwing that energy away, the system converts it back into electricity and stores it in the battery. It’s like getting a little “refund” every time you slow down. Most hybrid and electric cars do this automatically – the motor actually runs backwards during braking and acts like a generator. Pretty clever way to squeeze more miles out of your battery.

Regeneration – This is when your car’s exhaust system cleans itself automatically. In diesel vehicles with particulate filters, the engine gets really hot on purpose to burn off all the soot that’s built up in the filter.

Reinforcement profiles – The reinforcement profiles in doors and in side structures serve to stiffen the passenger cell and also for increasing the lateral collision safety. The warping or even tearing of the steel sheet will be restrained as best possible in the event of an impact due to stress distribution.

Remote Central Locking – This system lets you lock or unlock all your car doors at once using a key fob or remote control. When you press the button, it sends a signal to actuators inside each door that engage or release the locks simultaneously. Most modern systems also control the trunk and sometimes windows. The technology uses radio frequency signals, typically around 315MHz or 433MHz, to communicate between the remote and the car’s central locking module. If it stops working, check the remote battery first, then verify the door actuators and wiring connections.

Remote keyless entry – A radio frequency transmitter lets you lock and unlock your car doors from a distance. The transmitter works with on-board central, or power locking systems and anti-theft systems and is programmed to operate with frequencies and electronic codes specific to your car.

Rolling resistance – refers to the force required to move the tyre. Various factors affect rolling resistance. It depends on the type of tyre, on its width, tread pattern and the material composition of its tread. The loading of the car, too and, in particular, the air pressure greatly affect the rolling resistance. This is why it is important to check the air pressure regularly. In addition, a tyre with too little air pressure is subject to higher wear and the risk of failure increases drastically.

Roll-Over Bar System – The active roll-over protection system is located behind the rear head restraints. It works with the reinforced windscreen frame to provide extra crash protection for the car’s occupants. The system contains sensors that monitor the car’s progress. If they detect the risk of a rollover or impact, a dual-lever release system automatically turns the rear head restraints into a pair of robust rollover bars. These bars are housed in special cassettes bolted to the luggage compartment wall behind the rear seats. Once activated, they shoot upwards and are securely locked into place within 250 milliseconds.

RON Research Octane Number – This measures how well your fuel resists knocking or pinging in your engine. Higher RON numbers mean the fuel can handle more compression before it explodes on its own. Most regular gas is around 87 RON, premium is 91-93 RON. If your engine needs premium fuel, using lower RON gas will cause knocking, which sounds like marbles rattling and can damage your engine over time.

Roof pillars – an indispensable part of the geometry and structure of our cars. They help to maintain the structural integrity of the roof as well as complete the car’s safety cell.

Roof Rack – A mounting system that attaches to your vehicle’s roof to carry extra cargo like luggage, bikes, or kayaks. It consists of crossbars supported by towers or clips that secure to the roof rails or directly to the roof. Distributes weight evenly across the roof structure and typically has a weight limit of 100-200 pounds depending on your car’s specifications. Essential for transporting oversized items that won’t fit inside the vehicle.

Roof Rails – a feature that is found predominantly in estate cars or vans. Roof rails serve as a basic support for transporting things on the roof. With their help, the car can be put to varied use if the interior is already full. With suitable accessories for secure fastening, there is room on the roof rails for bicycles, skis, boxes, surfboards or even boats. Since the roof rails are aerodynamically shaped, they do not cause wind noise. Data about their load capacity can be found in the car’s manual. In addition to their practical use, roof rails are also used as a design element.

Rotational Angle Sensor – The navigation system’s rotational angle sensor senses changes in your car’s direction to the left or right. This information, combined with signals from the wheel speed sensors indicating the distance travelled, allows the navigation control unit to calculate the route being taken and the curve radius. This data is used for the purpose of dead reckoning navigation. This makes car positioning more accurate and lets route calculation continue in situations where your car is unable to receive GPS signals.

Safety Assist – These are electronic systems that help prevent accidents or reduce their severity. Common features include automatic emergency braking when sensors detect an obstacle, lane departure warning when you drift out of your lane, and blind spot monitoring that alerts you to vehicles you can’t see. The car uses cameras, radar, and sensors to constantly watch the road and either warn you of danger or take action automatically.

Safety Belts – These are the restraint straps that hold you in your seat during a crash or sudden stop. They work by spreading the impact force across your chest and pelvis – the strongest parts of your body. Modern seat belts have a retractor mechanism that locks up when pulled too fast, keeping you from flying forward. The shoulder strap goes across your chest, lap belt sits low on your hips. Always check that the belt clicks securely and isn’t twisted before driving.

Safety Cell – is the space in your car containing the driver and passengers. It forms a rigid safety cage. In contrast to the crumple zones of the car body, which are rugged but ultimately deformable, it is not easily deformed. As a result, it is able to protect the survival space of occupants in accidents up to a certain severity of impact.

Safety Pedals – Safety pedals are designed to minimise the risk of injury to the driver in a head-on accident. The programmed crumple zones ensures that the brake and clutch pedal do not penetrate further into the driver’s footwell during an accident. In the event of a frontal crash, the pedals are moved out of the way or disengaged by means of a lever mechanism.

Satellite Navigation – A system that uses GPS satellites orbiting Earth to pinpoint your car’s exact location and provide turn-by-turn directions to your destination. The receiver in your vehicle communicates with multiple satellites to calculate where you are, then displays your position on a digital map. Modern systems can also show real-time traffic conditions, suggest alternate routes, and even locate nearby gas stations or restaurants. It’s basically replaced paper maps and asking for directions.

SCR Selective Catalytic Reduction Catalyst – This is a diesel exhaust treatment system that injects DEF (diesel exhaust fluid) into the exhaust stream to break down harmful NOx emissions into harmless nitrogen and water. The SCR catalyst uses the ammonia from DEF to chemically convert pollutants before they exit the tailpipe. When it fails, you’ll see warning lights and possible derate conditions. Common issues include clogged injectors, faulty sensors, or contaminated DEF causing poor emissions performance.

SD Card Slot – SD cards are used as storage medium for digital data in various applications. They are also used, for instance, in order to store audio files in an MP3 format.

Seatbelt adjustable to height – This lets you move the shoulder strap up or down to fit your body properly. Look for a sliding clip on the door pillar that you can press and move. The belt should cross your chest, not your neck or shoulder. This keeps you safer in a crash and makes the ride more comfortable.

Seatbelt Force Limiter – The belt force limiter reduces the force of the seat belt above a certain threshold and, in conjunction with belt tensioners and airbags, lessens the risk of upper body injuries being caused to front passengers. In order to achieve this, a torsion bar in the belt retractor distorts under load. The system then releases the belt at a predefined force level. This reduces the maximum shoulder belt force and occupants are intercepted more gently by belt and airbag.

Seatbelt Pre-Tensioners – These are spring-loaded mechanisms built into your seatbelt system that instantly tighten the belt during a crash. When the airbag sensors detect an impact, the pre-tensioner fires and pulls any slack out of the belt in milliseconds, keeping you firmly against the seat. Once activated, the pre-tensioner is done – it’s a one-time use safety device that needs replacement after any accident where it deployed.

Seatbelt warning light – This dashboard indicator activates when the driver or passenger seat is occupied but the seatbelt isn’t fastened. The system uses weight sensors in the seats and seatbelt buckle switches to detect if someone is sitting down without buckling up. When triggered, it displays a warning light on the dash and often produces an audible chime. The light stays on until all occupied seats have their seatbelts properly fastened. This safety feature helps remind occupants to buckle up and meets federal safety requirements. If the light stays on even when belts are fastened, check for stuck buckle switches or faulty seat sensors.

Self Adjusting Clutch SAC – is a clutch system that automatically adjusts itself as the clutch disc wears down over time. Instead of needing manual adjustments, the SAC uses internal mechanisms like springs or ramps to maintain proper clutch pedal feel and engagement point. This keeps the clutch working smoothly throughout its life and reduces maintenance needs. When the clutch disc gets thinner from normal wear, the SAC compensates by automatically adjusting the pressure plate position. It’s commonly found in heavy-duty trucks and commercial vehicles where consistent clutch performance is critical.

Semi-Trailing Arm Rear Axle – This is a rear suspension setup where each wheel connects to the car body through an angled arm that pivots on a diagonal axis. Unlike a straight trailing arm that only moves up and down, the semi-trailing arm can also handle side-to-side forces when you turn corners. The arm is mounted at an angle – not straight across like a full trailing arm, and not completely lengthwise like a swing arm. This design gives you better handling than basic setups while keeping things simpler than fully independent systems. You’ll find this on many older European cars and some modern vehicles where they want decent performance without getting too complex or expensive.

Service Interval Display – This is a feature on your dashboard that tells you when your car needs maintenance. It counts down miles, kilometers or months until your next oil change or scheduled service. When it’s time, you’ll see a warning light or message pop up. You can usually reset it after getting your service done by holding down certain buttons – check your owner’s manual for the exact steps. It’s basically your car’s way of reminding you to keep up with regular maintenance so nothing breaks down on you.

Servo – is short for servomechanism – a powered mechanism producing motion or forces at a higher level of energy than that input. A car’s servo brakes, for example, greatly increase the force used by the driver to depress the brake pedal.

Servotronic Steering – designation consists of the following terms: power steering and electronics. It is so called the speed-dependent control of the power steering (conventional power steering operates with continuous power assistance). The lower the car speed is (for example, in urban traffic), the higher the support of the steering. In this way, manoeuvring is considerably much easier when parking. In the high-speed range, the steering power assistance is reduced; the driver is able to steer more accurately and keep the car safer on track, improving the directional stability.

Shock Absorber – A hydraulic damper that controls your car’s springs and keeps your wheels on the ground. When you hit a bump, the spring compresses and wants to bounce back hard. The shock absorber slows down that bounce using fluid resistance inside a cylinder. Without good shocks, your car would keep bouncing after every bump like a pogo stick. Bad shocks mean poor handling, longer stopping distances, and a rough ride. They wear out gradually, so you might not notice until they’re really shot.

Side Airbag – A safety cushion built into the side of your seat or door panel that inflates during a side-impact crash. It deploys in milliseconds to protect your torso and pelvis from hitting the door or intruding objects. Works with sensors that detect when your car gets hit from the side. Usually positioned at chest level in the seat back or sometimes in the door trim.

Side Impact Protection – This is a safety system designed to protect passengers when your car gets hit from the side. It includes reinforced door frames, side airbags, and extra steel beams built into the doors and pillars. When another vehicle or object hits your car’s side, these components work together to absorb the crash energy and keep it away from the passenger compartment. The side airbags deploy instantly to cushion your torso and head, while the reinforced structure prevents the door from crushing inward. It’s especially important because there’s less space between you and the impact point compared to front or rear crashes.

Side-Wind Compensation – This system automatically adjusts your steering when strong crosswinds try to push your car sideways. Sensors detect when the vehicle starts drifting from wind pressure, then the system makes small steering corrections to keep you going straight. You’ll feel less fighting against the wheel during windy highway driving. It’s especially helpful on bridges, open areas, or when passing large trucks that create wind gusts.

Synchronisation – This is when we match the speed of gears before they mesh together in your transmission. Without proper sync, you’d hear grinding noises when shifting gears because the gear teeth are trying to connect at different speeds. Your car has synchronizer rings (synchros) that use friction to speed up or slow down gears so they match perfectly before engaging. When synchros wear out, you’ll get that nasty grinding sound, especially going into second gear.

Snow Chains – Metal chains that wrap around your tires to give you better grip on snow and ice. They dig into the snow surface so your wheels don’t just spin uselessly. You install them by laying them flat, driving onto them, then connecting the links around the tire. They’re mandatory in some mountain areas during winter. Drive slow with chains on – they’re for traction, not speed. Remove them once you’re back on clear roads since they’ll damage your tires on dry pavement.

Soft-Touch – is an electric easy release for the hatchback door. It can be undone with a light tap on the handle.

Sound Proofing – This is adding materials to your car to block outside noise from getting in. Installed special foam, mats, or barriers in doors, floors, and panels to make the cabin quieter. Good sound proofing means you hear less road noise, wind, and engine sounds while driving. Makes for a more comfortable, peaceful ride.

Sound settings – These are the controls that let you adjust your car’s audio system. You can change things like bass, treble, balance (left/right speakers), and fade (front/back speakers). Most cars also have preset equalizer modes like “rock,” “jazz,” or “classical” that automatically adjust multiple sound frequencies. Some newer systems let you fine-tune individual frequency bands for a custom sound.

Speed Sensitive Power Steering – This system automatically adjusts how much power assistance you get based on your driving speed. At low speeds like parking, it gives you maximum help so the wheel turns easily. As you drive faster on highways, it reduces the assistance so you get better road feel and more precise control. It uses sensors to monitor your speed and adjusts the power steering pump or electric motor accordingly. This gives you the best of both worlds – easy maneuvering in tight spots and stable handling at high speeds.

Sport Chassis – A stiffer, lower suspension setup that reduces body roll and improves handling. The springs are firmer, shock absorbers are tuned for better control, and the ride height is typically dropped. Makes the car feel more connected to the road but trades some comfort for performance. You’ll feel bumps more, but the car won’t lean as much in corners and responds quicker to steering inputs.

Sports Seats – These are specially designed car seats that hold you tight during aggressive driving. They have deeper side bolsters (the raised parts on the sides) that wrap around your body to prevent sliding when you take corners fast. The seats usually sit lower than regular seats and have firmer padding for better feel and control. Many sports seats also feature things like adjustable lumbar support, thigh extensions, and sometimes racing harness slots. They’re built to keep the driver planted in position so you can focus on driving instead of bracing yourself in the seat.

Spring-damper system – This is your car’s shock absorber setup that keeps you comfortable on bumpy roads. The spring part bounces up and down when you hit a pothole, while the damper (shock absorber) controls that bouncing so it doesn’t keep going forever. Without it, your car would bounce like a trampoline after every bump. The spring handles the weight, the damper smooths out the ride. That’s why worn shocks make your car feel bouncy and unstable – the damper isn’t doing its job anymore.

Stabiliser – A metal bar that connects the left and right wheels to reduce body roll when cornering. When you take a turn, the car wants to lean to one side. The stabiliser bar twists and pushes back against this lean, keeping the vehicle more level and improving handling. Also called a sway bar or anti-roll bar. Common signs of wear include clunking noises over bumps and excessive body roll in turns.

Start-Stop System – This automatically shuts off your engine when you’re stopped (like at red lights) and restarts it when you’re ready to go. It saves fuel and reduces emissions during idle time. As a tech, I see these systems use sensors to monitor clutch position, brake pedal, and gear selection. The starter motor is beefed up to handle frequent restarts, and the battery is usually upgraded too.

Steering Column – The vertical shaft that connects your steering wheel to the steering gear box. It’s basically a metal tube with joints that lets you turn the wheel and have that motion transfer down to actually steer the tires. Most modern columns also house your turn signals, wipers, and other controls. When it goes bad, you’ll feel loose or binding steering, or your wheel might not return to center properly.

Specifications of weight – These are the official weight measurements for a vehicle. We measure curb weight (car with fluids but no passengers), gross vehicle weight (maximum safe loaded weight), and payload capacity (how much cargo you can carry). As a tech, I check these specs to ensure proper tire pressure, suspension setup, and towing limits. Weight affects everything from fuel economy to braking distance, so knowing these numbers helps me diagnose issues and keep the vehicle running safely within its design limits.

Tailored Blanks – refers to a raw sheet that features different thicknesses. It makes the welding of several different strong parts superfluous and it significantly reduces the cost of materials during manufacture. For the manufacture of tailored blanks, the mash seam welding method is also used in addition to the laser welding. During this welding process, the parts, which are to be joined, are guided between two roller electrodes. Tailored blanks provide low cost materials while offering the same stability versus conventional steel sheets. In addition to its low weight, which has a positive effect on fuel consumption, they also offer the advantage of easier installation and increased stability.

TDI Turbo Diesel Injection – This is Volkswagen’s name for their turbocharged diesel engine system. The “TDI” combines two key parts: a turbocharger that forces more air into the engine for extra power, and direct injection that sprays diesel fuel straight into the combustion chamber at high pressure. This setup gives you better fuel economy and more torque than regular diesel engines. You’ll find TDI engines in VW, Audi, and some other European cars. They’re known for running efficiently and lasting a long time when properly maintained.

Telescopic Shock Absorber – This is the most common type of shock absorber you’ll find on modern cars. It’s called “telescopic” because it works like a telescope – one tube slides inside another tube. The shock has two main parts: an outer tube and an inner piston rod that moves up and down. When your wheel hits a bump, the piston moves through oil inside the tube. This oil flow is controlled by small valves, which creates resistance and dampens the bouncing motion. Most cars use these because they’re compact, reliable, and can handle both compression (when the wheel goes up) and rebound (when it comes back down) in one unit.

TFSI Turbo Fuel Stratified Injection – This is Audi’s name for their turbocharged direct injection engine. The fuel gets sprayed directly into the cylinder instead of the intake port. “Stratified” means the fuel mixes in layers – rich mixture near the spark plug, lean mixture everywhere else. This gives you better fuel economy and more power. The turbo adds extra air pressure to pack more fuel and air into each cylinder. Bottom line: it’s an efficient way to get good performance while saving gas.

TGI Technology – TGI is the brand name for engines which can operate with both natural gas and petrol. The engine operates primarily with natural gas. Once the gas tank is empty, it will automatically switch to petrol. TGI Technology features low emissions and particularly low fuel consumption. Moreover, technology has another advantage: huge ranges are possible due to the two separate tanks.

Three-way catalyst – It’s the main part of your catalytic converter that cleans up three different nasty gases coming from your engine. Takes carbon monoxide, nitrogen oxides, and unburned hydrocarbons and turns them into harmless water vapor and carbon dioxide. That’s why it’s called “three-way” – handles three types of pollution at once. Without it working properly, your car may fails emissions.

Tilt Angle – This is the angle at which a car can drive diagonally across a slope without tipping over. The tilt angles determined at the factory have been measured statically on a ramp. The car, while stationary, is tilted until it tips over on its side. Larger tyres or a raised chassis worsen the tilt angle.

Time Delay Interior Lights – These lights stay on for a set period after you close your car doors, usually 15-30 seconds. They give you time to get settled, find your keys, or grab items without fumbling in the dark. The system uses a timer relay that cuts power to the dome and courtesy lights after the programmed delay. Most cars let you adjust this timing through the vehicle settings or by cycling the headlight switch. If the lights stay on too long or won’t turn off, check for faulty door switches or a bad timer module.

Timing – refers to the coordinated synchronized process by which intake and exhaust valves open and close and spark plugs fire in precise sequence with piston movement.

Types Of Collision – There are three main ways cars crash that we see in the shop every day. Head-on collision happens when two vehicles hit front-to-front. These cause the most damage because both cars’ speeds combine on impact. You’ll see crushed engine compartments and deployed airbags. Side-impact collision is when one car hits another from the side, making a “T” shape. The doors get smashed in and window glass usually shatters. We call these T-bone crashes. Rear-end collision occurs when one vehicle hits another from behind. Usually damages the trunk, rear bumper, and sometimes pushes the rear axle forward. Front car might have whiplash damage to seats. Each type creates different damage patterns, so we know what to look for when the tow truck brings them in.

Tiptronic – It’s an automatic transmission that lets you shift gears manually when you want to. You can drive it like a regular automatic, or move the gear lever to a special position and push it forward or back to change gears yourself.

Tiredness Recognition System – This safety feature monitors your driving behavior to detect when you’re getting drowsy behind the wheel. The system uses sensors to track things like steering wheel movements, lane position, and how often you’re making small corrections. When it notices erratic patterns that suggest fatigue, it alerts you with visual warnings on the dashboard or audio chimes. Some advanced versions also monitor your eye movements and blinking patterns through a camera. If drowsiness is detected, the system typically suggests taking a break and may even show nearby rest stops on your navigation display. It’s designed to prevent accidents caused by falling asleep while driving.

Tyre Mobility Set – A temporary repair kit that replaces your spare tyre. It contains a bottle of sealant and a small air compressor. When you get a puncture, you inject the sealant into the tyre through the valve, then pump it up with the compressor. The sealant plugs small holes and gets you moving again. It’s not a permanent fix – you still need to get the tyre properly repaired or replaced. Only works on punctures in the tread area, not sidewall damage or big tears.

Tyre-pressure monitoring display – This is the screen or gauge on your dashboard that shows the air pressure in each of your tyres. It gets information from sensors inside the wheels and warns you when pressure drops too low. Most modern cars have this built into the instrument cluster or infotainment screen. When a tyre loses pressure, you’ll see a warning light or exact pressure readings for each wheel. It helps prevent blowouts and improves fuel economy by keeping tyres properly inflated.

Tyres – The rubber components that make direct contact with the road surface. They’re mounted on wheel rims and filled with air to support the vehicle’s weight. Tyres provide traction for acceleration, braking, and steering while absorbing road impacts. They contain steel belts and fabric plies for strength, with tread patterns designed for grip and water drainage. Regular pressure checks and tread depth monitoring are essential for safety and performance.

Tyres with reduced rolling resistance – a tyre is constantly deformed by the loads it is exposed to during driving. Depending on the contact surface and the tyre air pressure, this deformation has a cost in terms of energy and therefore of fuel. Through the use of special heat-resistant and deformation-resistant materials in the tread and sidewall, deformation of the tyre is reduced and energy losses are minimised. Reduced rolling resistance tyres also possess special rubber blends, thus increasing ride comfort and helping to reduce the fuel consumption and emissions of the car.

Tyres With Run-Flat Properties – These are special tyres that can keep rolling even after getting punctured or losing air pressure. They have reinforced sidewalls that support the car’s weight when there’s no air inside. You can usually drive about 80 kilometers at speeds up to 80 km/h to reach a safe location or tire shop. They’re designed to prevent dangerous blowouts and eliminate the need for immediate roadside tire changes.

TMC Traffic Message Channel – This is a digital radio system that sends real-time traffic information to your car’s navigation system. It broadcasts coded messages about accidents, road closures, and traffic jams through FM radio signals. Your GPS receiver decodes these messages and automatically updates your route to avoid delays. It runs in the background without interrupting your radio listening. Most modern cars with built-in navigation have TMC capability, though it’s being replaced by internet-based traffic services in newer vehicles.

Top Tether – This is a useful complement to the Isofix anchorage system for child seats. With Isofix, two claws connect the seats to the bodywork only at the bottom, while an additional upper breakpoint (Top Tether) supplements the fasteners.

Top View Camera – Parking a car is now easier than ever. Cameras placed in the front, the rear and the exterior mirrors mean you can see what’s around every corner. 360º views of the surroundings of the car while parking, with dynamic lines to guide the driver through the parking manoeuvre enhance comfort and make parking a pleasure.

Torque – This is the twisting force your engine produces to turn the wheels. You feel it as the pulling power when you accelerate from a stop or climb a hill. Measured in pound-feet (lb-ft) or Newton-meters (Nm), torque determines how much work your engine can do. More torque means better pulling power for towing, hauling loads, or quick acceleration from low speeds. Your engine makes peak torque at a specific RPM range – usually lower RPMs than peak horsepower. That’s why diesel engines, which produce high torque at low RPMs, excel at heavy-duty work. When you press the gas pedal and feel that immediate push back into your seat, that’s torque doing its job.

Torque Converter – This fluid-filled coupling connects your engine to the automatic transmission. It uses transmission fluid to transfer power from the engine’s crankshaft to the transmission input shaft. Inside, you’ll find an impeller (connected to the engine), turbine (connected to transmission), and stator. When the engine spins the impeller, it pushes fluid against the turbine blades, creating rotation. The stator redirects fluid flow to multiply torque at low speeds. At highway speeds, most torque converters “lock up” with a clutch to eliminate slippage and improve fuel economy. When this lockup clutch fails, you’ll feel shuddering during acceleration or notice higher RPMs without corresponding speed increase. Common problems include worn internal seals causing slippage, contaminated fluid, or lockup clutch failure. Regular transmission fluid changes help prevent most torque converter issues.

Torsion Beam Rear Axle – The torsion beam rear axle has proved itself as the most economical layout for non-driven rear axles. Two trailing arms are connected by means of a cross member, which also serves as a stabiliser. The advantages of this type of design lie in the good lateral stability it offers when cornering and in its extremely space-saving design, which permits good use of space in the rear.

Torsion Beam Rear Suspension – is the most economical layout for non-driven rear axles. Two trailing arms are linked by means of a cross member, which also serves as an anti-roll bar. The advantages of this layout are good directional stability when cornering and a compact design, making for convenient use of space at the rear.

Traction Control Anti-Slip Regulation ASR – This system prevents your wheels from spinning when you accelerate, especially on slippery surfaces like wet roads or loose gravel. The ASR monitors wheel speed through sensors. When it detects one wheel spinning faster than others, it automatically reduces engine power or applies brakes to that specific wheel. This keeps all wheels gripping the road properly. You’ll find this system most helpful when starting from a stop on ice, accelerating up a hill, or driving through mud. The ASR light on your dashboard will flash when the system is actively working to control wheel spin. Most modern vehicles have this feature integrated with the stability control system. It works automatically – you don’t need to do anything. However, some cars have an ASR off button for situations like getting unstuck from deep snow where controlled wheel spin might actually help.

Traction Control System TCS – prevents your wheels from spinning when you accelerate on slippery surfaces like wet roads, snow, or ice. The system monitors wheel speed through sensors. When it detects one wheel spinning faster than others, it automatically reduces engine power or applies brakes to that specific wheel. This keeps all wheels gripping the road evenly. You’ll see a TCS warning light on your dashboard when the system activates. Most vehicles let you turn TCS off with a button, but I recommend keeping it on for normal driving. TCS works with your ABS brakes and helps maintain control during acceleration, especially when turning corners or starting from a stop on slippery roads.

Traffic Jam Assist – This system takes over steering, braking, and acceleration when you’re stuck in slow-moving traffic. It keeps your car centered in the lane and maintains a safe distance from the vehicle ahead. You still need to keep your hands on the wheel and stay alert, but the car handles the stop-and-go driving automatically. The system uses cameras and sensors to monitor traffic flow and lane markings, making those long traffic jams much less stressful on your hands and feet.

Traffic Sign Recognition – This system uses cameras and computer software to automatically detect and read road signs while you’re driving. The camera scans ahead, identifies signs like speed limits, stop signs, or no-entry warnings, then displays the information on your dashboard or instrument cluster. It helps prevent you from missing important signs, especially in unfamiliar areas or poor visibility conditions. Some advanced versions will even alert you if you’re exceeding a detected speed limit.

Trailer Assist – An automated system that helps drivers back up with a trailer attached. You turn a knob or use controls to indicate which direction you want the trailer to go, and the system automatically steers the vehicle to guide the trailer into position. The system uses sensors and cameras to monitor the trailer’s angle and position, making corrections to prevent jackknifing. This eliminates the guesswork and reverse steering technique normally required when backing up trailers, making it much easier for inexperienced drivers to maneuver safely.

Trailer hitch – A mounting system that bolts to your vehicle’s frame to connect and tow trailers, boats, or cargo carriers. The hitch consists of a receiver tube that accepts a ball mount or other towing accessories. Different classes handle varying weight capacities, from light utility trailers to heavy RVs. Proper installation requires mounting to structural frame points with grade-8 bolts and following manufacturer torque specifications. Always match your hitch class to your vehicle’s towing capacity and trailer weight for safe operation.

Trailer stabilisation – A safety system that prevents your trailer from swaying or fishtailing while you’re driving. When sensors detect the trailer starting to wobble side-to-side, the system automatically applies brakes to specific wheels on both your vehicle and trailer to bring everything back in line. This keeps you in control, especially during emergency maneuvers, crosswinds, or when passing large trucks. Most modern vehicles with towing packages have this built-in and it activates without you doing anything.

Trapezoidal-link Rear Axle – features a lower trapezium-shaped link, an upper wishbone and a track rod located behind the trapezoidal link. The spring is connected to the trapezoidal link and the damper is coupled to the wheel carrier in a space-saving layout. This design produces excellent driving and handling characteristics with outstanding comfort. The driving stability, especially when cornering, is better than the stability from other constructive solutions although the costs are also higher.

Trapezoidal-Link Rear Suspension – is a type of suspension that features a special wheel carrier with a lower trapezium-shaped link, an upper transverse link and a track rod located behind the trapezoidal link. The spring is connected to the trapezoidal link and the damper is coupled to the wheel carrier in a space-saving layout. This design produces excellent driving and handling characteristics with outstanding ride comfort.

Triangular Wishbone – is a component of automobile suspension. Wishbones are installed across the car perpendicular to the direction of travel and connect the wheel mount either with the axle (eg: multi-link rear suspension) or directly to the body (eg: MacPherson independent suspension). At each end they have in each case at least one connection supported on bearings (ball joint and/or rubber-metal composite bearing) and thus allow for the vertical movement of the suspension. The function of the wishbone is mainly to take up horizontal forces, such as occur when accelerating or braking and cornering.

Trip Computer – the trip computer provides the driver with essential driving data such as average fuel consumption on a display in the instrument cluster. This information is used by the computer to calculate how far you can drive with the amount of fuel left in the tank. The data also helps you drive in an efficient and economical way. You can also call up extra information on average speed or total driving time.

TSI Turbo Stratified Injection – This is Volkswagen’s engine technology that combines direct fuel injection with turbocharging. The system injects fuel directly into the combustion chamber at precise moments and uses a turbocharger to force more air into the engine. This creates better fuel mixing, improves combustion efficiency, and delivers more power while using less fuel. You’ll find TSI engines produce strong torque at low RPMs and offer better fuel economy compared to traditional engines of similar power output.

Turbocharger – A turbine-driven forced induction device that compresses air entering the engine. It uses exhaust gases to spin a turbine wheel, which drives a compressor wheel that forces more air into the cylinders. This allows the engine to burn more fuel and produce significantly more power than a naturally aspirated engine of the same size. The turbocharger increases engine efficiency and performance while maintaining smaller displacement, making it popular in modern vehicles for better fuel economy without sacrificing power output.

Turning Circle – This measures how tight a car can turn around. It’s calculated by measuring the diameter of the smallest circle your vehicle makes when you turn the steering wheel fully to one side. A smaller turning circle means better maneuverability in tight spaces like parking lots. Longer vehicles and those with wider wheelbases typically have larger turning circles. Most compact cars have turning circles around 32-36 feet, while full-size trucks can reach 45+ feet. This specification helps you determine if a vehicle will fit your driving needs, especially for city driving or frequent parking situations.

Two-stage Brake Servo – The brake servo reduces the force you need to put on the brake pedal. The two-stage brake servo represents an innovation. Up to a brake pressure of about 45 bars, known as the comfort braking range, the brake servo operates with a strengthening of factor 5. If the driver steps harder on the brake, this braking force increases up to factor 10. The driver notices this through a faster braking behaviour on the short pedal, as well as good control and reduced braking effort, up to the point where the ABS is activated.

Underbody Cladding – In the place of classical underbody protection, we’ve been making more use of plastic cladding. This effectively protects the underbody against damage due to stone chippings, is lighter and can be recycled, making it more environmentally friendly. In addition, this cladding improves the aerodynamic characteristics of the car body and decreases drag, which in turn means lower fuel consumption.

Understeering Driving Behaviour – Understeering means that, when cornering, the front wheels have exceeded their liability limit and the car pushes over the front axle to the outer edge of the curve.The steering must be strongly taken, since it would be required according to the radius of the curve. This driving behaviour is easier to control than oversteering since, thanks to this feature, the car remains stable and even slows down. Thus, it offers the driver more safety.

Upper Dead Center, Lower Dead Center – The top or bottom dead center refer respectively to the highest or lowest point that the piston reaches during its up and down movement in the cylinder, in other words, the respective point where the piston reverses direction.

USB / iPod Interface – Situated in the glovebox, the USB / iPod interface lets you connect your MP3 player, USB stick or iPod so that you play your choice of music from your own external audio device, via your car’s sound system. It allows you fast and easy access to the files stored on your MP3 player, iPod and USB memory stick. Folders or menus can be navigated via the car’s sound system, with the track playing shown on the radio or radio-navigation display. The port also supplies a 5-volt charging current.

Variable Camshaft Adjustment – The camshaft has the task of operating the valves at the right time and in the correct order and to control the gas exchange. The camshaft regulation optimally adjusts the opening times of the valves in all operating conditions. In engines with a double overhead camshaft, the size and positioning of the valve opening overlap can be influenced, enhancing characteristics in full-load and part-load operation.

Variable Intake Manifold – The air required for combustion in the engine flows through the variable intake manifold to the intake valve. Nowadays, common fuel injection systems for petrol engines inject the fuel in the intake manifold immediately prior to the intake valve. The length of the intake manifold may be variable at different engine performance conditions, actually setting contradictory requirements, so the highest possible air inflow speed and proper cylinder filling can be guaranteed at all engine speeds. While the priority at low revolutions is to deliver torque as rapidly as possible, best attained by means of a long intake manifold, the need for maximum power output at high revolutions requires short intake manifolds. The variable intake manifold complies with an electronically controlled flap system that meets both those demands, channelling the air via the long intake manifold at low revolutions and through the short intake manifold at high revolutions.

Variable Turbine Geometry – The majority of TDI engines are turbocharged using variable turbine geometry to offer an almost constant boost pressure across the widest rev range. Variable turbine geometry continually adjusts output to ensure all exhaust gas energy is used to regulate boost pressure. Adjustable vanes maintain level boost pressure across a wide control range. Where gas pressure falls at low speed, or rises at high speed, the automatic vane adjustment increases or decreases the supply line cross-section. This variable geometry turbocharger is particularly efficient in reducing turbo lag at partial load, increasing power, improving response and helping reduce emissions.

Variable Turbocharger Geometry – This system adjusts the turbocharger’s internal vanes to control exhaust gas flow. At low RPMs, the vanes close to create higher exhaust velocity, spooling the turbo faster for better low-end power. At high RPMs, they open wide to allow maximum airflow without restriction. This eliminates turbo lag while preventing over-boost at high speeds. You’ll find this technology mainly on diesel engines where it significantly improves throttle response and fuel efficiency across the entire RPM range.

Variable Valve Timing – the function of the camshaft is to operate the valves at the right time and in the right order to control the charge cycle. Variable valve timing adjusts the opening times of the valves to suit all operating conditions. This ensures ideal charge cycles within a wide range of engine speeds and loads. Fuel consumption and emissions are reduced, torque and smoothness are increased.

Ventilated disc brakes – The disc brake is a very stable and efficient mechanism. It is clasped by the calliper which in turn holds the brake pads. The temperature of a disk brake may rise as high as 500°C, but its tendency to fade is still low. For better cooling, the front discs are usually ventilated. With high-performance cars, flow-optimised wheels may facilitate the cooling function. Ventilated disc brakes are easy to apply, guarantee a safe reduction of speed and can thus avoid accidents or reduce the consequences of accidents. Even after many braking cycles, effectiveness is ensured by the internal ventilation.

Wheelbase – The distance between the center of the front wheels and center of the rear wheels. Longer wheelbase gives better stability but reduces turning ability.

Water Pump – Circulates coolant through the engine to prevent overheating. When it fails, your engine will overheat quickly.

Wiring Harness – Bundle of electrical wires that connects all electrical components in your vehicle. A damaged harness causes multiple electrical problems.

Wheel Alignment – Adjusting wheel angles to manufacturer specifications. Poor alignment causes uneven tire wear and steering pull.

Wastegate – Controls turbocharger boost pressure by releasing exhaust gases. Prevents engine damage from excessive boost.

Wiper Motor – Electric motor that operates windshield wipers. Usually fails gradually, starting with slow operation before stopping completely.

Wheel Bearing – Allows wheels to rotate smoothly around the axle. Bad bearings create grinding noise and wheel wobble.

Water Temperature Sensor – Monitors engine coolant temperature for the computer. Faulty sensor causes poor engine performance and cooling fan issues.

Winch – Mechanical device using cable or rope to pull heavy loads. Common on off-road vehicles for recovery operations.

Wrench – Hand tool for gripping and turning nuts and bolts. Essential tool for any automotive repair work.

Xenon Headlights – High-intensity discharge lamps that produce bright white light using xenon gas. They’re much brighter than regular halogen bulbs and last longer, but cost more to replace.

X-Frame – A chassis design where the frame rails cross in an X pattern under the vehicle. This provides structural strength while reducing weight, commonly used in sports cars and trucks.

XDrive – BMW’s all-wheel drive system that automatically distributes power between front and rear wheels based on traction conditions. It improves handling and stability in various driving situations.

X-Pipe – An exhaust system component where two exhaust pipes cross and connect, forming an X shape. This design balances exhaust flow between cylinders and can improve engine performance and sound.

Xenon Arc Welding – A welding process used in automotive manufacturing and repair that uses xenon gas to create a stable electric arc. It produces clean, precise welds on thin metal panels.

Yaw – Rotational movement of a vehicle around its vertical axis. When your car spins left or right during a skid, that’s yaw motion. Electronic stability control systems detect and correct excessive yaw to keep you driving straight.

Yoke – Heavy-duty coupling device that connects the drive shaft to the differential. It transfers power from the transmission to the wheels. Common failure points include worn universal joints and damaged splines.

Y-pipe – Exhaust component where two separate pipes merge into one. Usually found where dual exhaust headers join before the catalytic converter. Cracked Y-pipes cause exhaust leaks and noise.

Yokohama – Japanese tire manufacturer known for performance and racing tires. Popular choice for sports cars and track applications due to their advanced rubber compounds and tread designs.

Yaw sensor – Electronic component that measures vehicle rotation rate. Works with the stability control system to detect when the car isn’t going where you’re steering. Faulty sensors trigger warning lights and disable safety systems.

Zerk Fitting – A grease fitting with a spring-loaded ball that allows grease guns to inject lubricant into bearings and joints. Push the grease gun nozzle onto the fitting and pump.

Zone Control – System that divides vehicle climate control into separate areas. Each zone can have different temperature settings controlled independently.

Z-bar – A Z-shaped linkage connecting the clutch pedal to the clutch release mechanism in older manual transmission vehicles. Transfers pedal movement to disengage the clutch.

Zero Emission Vehicle (ZEV) – Vehicles that produce no exhaust emissions during operation. Electric vehicles and hydrogen fuel cell vehicles qualify as ZEVs.

Zener Diode – Electronic component in charging systems that regulates voltage by allowing current flow only when voltage exceeds a specific level. Protects electrical components from overcharge.

Zinc Coating – Protective layer applied to metal parts to prevent rust and corrosion. Common on brake lines, fuel lines, and body panels.

Zone Valve – Controls coolant flow in heating systems. Opens and closes to direct heated coolant to specific areas like passenger compartment or engine block.

Disclaimer: Car terminology and specifications may vary between different automotive manufacturers and brands. The terms, features, and technical descriptions referenced may not be universally standardized across all vehicle makes and models. Always consult your specific vehicle’s owner’s manual or contact your authorized dealer for accurate information pertaining to your particular car brand and model.