Active Cylinder Management ACT  

Treating resources responsibly: this aim, pursued by Volkswagen, explains the introduction of Active Cylinder Management. For journeys in an engine speed range between 1,400 and 4,000 rpm and at speeds of up to 130 km/h, two of the four cylinders can be deactivated with no perceptible effect, irrespective of the gear selected. This optimises engine efficiency. The multifunction display informs you which mode the engine is currently in.
In vehicles with Active Cylinder Management ACT, fuel consumption can be reduced by up to 0.5 l/100 km and CO2 emissions by 10 g/km in a combined driving cycle. Depending on the driving situation, savings of up to 1 l/100 km are even possible.

A VW Golf’s cylinder

Active Info Display

The Active Info Display supplies vehicle data and information straight to the cockpit. The high-resolution screen replaces the original speedometer and allows the user to adapt five different views to their needs.
For instance, in navigation mode, the speedometer and rev counter move to the edge to allow more space for the map. However, if desired, information such on driving, navigation and assist functions can also be included in the speedometer and rev counter interfaces. The Active Info Display is also connected to other assist systems in the vehicle. This allows infotainment system data shown in the centre console, such as telephone contact images or CD covers, to be displayed directly in the driver’s field of vision.

View of the Active Info Display through the steering wheel

Active recuperation

Active recuperation is a comfort and safety feature of Volkswagen's electromechanical power steering. The feeling of being centred and the building steering torque at the slightest steering angles convey a previously unseen precision. The active recuperation improves steering comfort and the feeling of safety, as fewer steering corrections need to be made.

Engine and wheel rims on the VW Golf R, view from below

Active safety

Active safety encompasses all systems which actively intervene in driving activity to help defuse emergency situations. The main aspects of active safety are as follows:

  • Driving stability: This results in particular from the running gear design with regard to drive concept, suspension and corner stability. Steering precision, brake performance and brake stability are also involved.
  • Condition safety: This describes the impact on occupants caused by vehicle vibrations, noises from the running gear and engine and climatic influences.
  • Perceptual safety: This is improved in particular by good lighting system arrangements and visibility conditions (panoramic view, good view of the rear in the smallest blind corners possible).
  • Operating safety: this is achieved specifically through good ergonomics and logical arrangement of all operating levers and switches, e.g. for lighting, wipers, air conditioning or infotainment. The elements must be as easy as possible to reach from the driver’s seat.

The combination of active and passive safety features ensure optimum protection of all vehicle occupants.

Schematic diagram of the active safety systems in a Volkswagen

Adaptive chassis control DCC  

The adaptive chassis control improves the vehicle’s driving characteristics dramatically. The driver is no longer tied to a specific running gear design and can adapt their vehicle to suit them. They can make their selection with ease at the touch of a button in the centre console.
They can choose a normal, sporty or comfort setting. The electric damping adjustment adjusts automatically. The system reacts constantly to different driving situations.

Schematic diagram of the adaptive chassis control DCC using the example of a VW Golf

Adaptive chassis with active roll stabilisation

The adaptive chassis with electromechanical active roll stabilisation can reduce rolling on corners. As it is electromechanical rather than hydraulic, like conventional stabilisers, the system can react much more quickly within its limits and operate even at low speeds. This enables a palpable boost in steering precision, agility, stability and traction on uneven terrain.


Schematic diagram of an adaptive chassis with electromechanical active roll stabilisation using a Touareg as an example.

Adaptive Cruise Control ACC  

Adaptive Cruise Control ACC uses a distance sensor to measure the distance and speed relative to the vehicles in front.
To do this, the driver sets the speed and the required trailing distance in terms of time. When following vehicles, target and actual distance can be shown by way of comparison in the multifunction display.
A sensor monitors the area in front of the vehicle constantly. The driver can use the accelerator to end ACC and accelerate faster. Pressing the brake pedal immediately deactivates the ACC function. All system notifications are shown in the central multifunction display.
In conjunction with a dual clutch gearbox, ACC brakes the vehicle to a standstill, for instance, in queues or traffic situations. Depending on the situation, the ACC will then start again itself within a set period of time.
Depending on vehicle equipment, ACC can be activated up to a speed of 160 km/h or 210 km/h (Touareg up to 250 km/h).

See also:
Driver assist systems
‘Front Assist’ area monitoring system

Two Volkswagen vehicles seen from above at night. Schematic view of the Adaptive Cruise Control ACC sensor system

Adaptive suspension 

With adaptive suspension, the vehicle’s air suspension can be kept at a constant level on both axles, irrespective of the vehicle’s load level.1 Four height sensors constantly determine the distance between the axles and vehicle body. Differences from the target distance can therefore be offset immediately.1

Different systems are used to compensate in conventional suspension and air suspension. Automatic adaptive suspension can lead to more driving comfort as it helps prevent the rear of the vehicle from sinking when loaded.1 Adaptive suspension can also make journeys with trailers more workable.

1 within the system’s limitations

See also:
Air suspension (CDC)

Schematic diagram of the air suspension with adaptive suspension


The SCR (selective catalytic reduction) catalytic converter converts the exhaust gas component nitrogen oxide (NOx) selectively into nitrogen and water without the formation of undesired side products. The conversion is performed using the synthetic 32.5 per cent reducing agent AdBlue® (ISO 22241-1 / AUS 32), which is added to an additional tank. The dosage is based on the exhaust gas flow rate; engine management in conjunction with an NOx sensor behind the SCR catalytic converter ensure a precise dosage.
Depending on the vehicle, the customer may also have to top up AdBlue® themselves, or have it topped up by their authorised workshop, between services. provides a free service helping customers who top up themselves find suitable filling stations.

See also:
NOx exhaust gas treatment

Ansicht eines Cockpit Displays mit Anzeigen der Füllstände AdBlue

Additional instrument 

The displays in the additional instrument above the centre console - optionally available or part of special equipment bundles for the Scirocco, Beetle and Beetle Cabriolet - inform the driver of charge pressure and engine oil temperature. The multifunctional stopwatch measures idle time and journey times.

VW additional instruments with engine oil temperature control, turbo charge pressure control and centre function stopwatch

Ad hoc charging

With ad hoc charging, the operator of the charging station is paid directly for any current bought.


The aerodynamics of a vehicle’s body have an impact on fuel consumption, maximum speed and noise emissions. The drag coefficient detected in the wind tunnel sums up the aerodynamic properties. This value is affected by different sizes, such as the body shape (saloon, van or hatchback). The design of the underbody also has an impact. The drag is produced by the displacement of the air surrounding the vehicle and its friction with the vehicle surface.

The formula for calculating drag is as follows:
Drag = vehicle speed squared x end face x Cd x ½ air density.

The typical economical Volkswagen body design and narrow panel gaps and spaces reduce turbulence and facilitate a low level of drag, ensuring economical consumption levels and lower CO2 emissions. However, the most important influencing factor is the vehicle speed, as when the speed doubles, drag quadruples.

See also:


VW Golf R on a racetrack, front view
Fuel consumption Golf R in l/100 km: urban 8.2-8.1 / extra-urban
6.6-6.5 / combined 7.2-7.1; CO₂ emissions combined, g/km: 164-162;
efficiency class: D


Together with the seat belt, airbags reduce the risk of severe injuries to the head and chest in collisions causing correspondingly severe accidents. If the crash sensors record an impact that meets the trigger value, the airbag control unit starts the gas generator. It fills the airbag within 35 to 45 milliseconds. The activated airbags restrain the head and upper body and distribute the impact over as wide an area as possible. After just 120 milliseconds, the gas has escaped and the airbag has collapsed. Optimum protection is only provided if the vehicle occupants are properly strapped in, as the airbags and belt tensioner work together to form a coordinated safety system. As well as the front airbags, side airbags, knee airbags and a curtain airbag system are also available.

See also:
Crash test

Schematic diagram of two curtain airbags in a Golf

Airbag control unit

The airbag control unit detects and measures a collision and activates the relevant restraint systems according to the type and severity of the accident. Up to six external acceleration sensors (crash sensors) supply the control unit with information.
The airbag control unit is equipped with accelerator sensors for the vehicle’s longitudinal, transverse and vertical axes. The control unit also has a yaw rate sensor, which records the vehicle’s rotation along its longitudinal axis. The sensors in the control unit measure and compare the signals from the other sensors. This allows the control unit to assess the direction and severity of the accident and to trigger the relevant restraint systems. The control unit is connected to other CAN data bus systems via the crash signal outputs, to make orientation and rescue of occupants easier after an accident.
Volkswagen’s extensive research and constant development have helped refine control of the restraint systems so they offer optimum protection in a wide range of different types of accidents. The two-step triggering of the front airbag, which depends on the severity of the accident, helps reduce the risk of injury further for drivers and passengers. The system can distinguish between an accident and a strong shock, which might be caused by impact from a stone or a deep pothole, for instance. This ensures that no restraint systems are triggered if the vehicle has not crashed.

Schematic diagram of the airbag control unit in a Volkswagen

Air conditioning system 

The main components of the air conditioning system are the cooling system, heating and blower unit. It enhances a vehicle's ventilation system.

Volkswagen offers a semi-automatic air conditioning system and a ‘Climatronic’ automatic air conditioner for its models.

‘Climatronic’ regulates the interior temperature based on a preset preferred temperature, automatically adjusting the blower speed and operating the air distribution flaps. It therefore offers a comfortable climate in practically all operating and weather conditions and air flow through the passenger compartment with as little draught as possible. The ‘Climatronic’ electronic control system records all major influencing factors and disturbances and supplies more or less cool air accordingly.

Additional comfort features are available thanks to integration of the control unit into the CAN bus: Automatic air recirculation on activating windscreen washing or going into reverse gear protects vehicle occupants from unpleasant odours. The speed-based blower speed control with automatic vent temperature adjustment reduces noise levels on slow journeys.

‘Climatronic’ also activates the defrost function for foggy or icy windows at the touch of a button. At high blower capacity, the entire air flow is steered towards the inside of the window. If the outside temperature is over 2.5 °C, the cooling system also kicks in to dry the air.

In this way, ‘Climatronic’ by Volkswagen improves the wellbeing of vehicle occupants and boosts comfort and visibility. The pleasant temperature control helps maintain the driver’s ability to react and concentrate.

Depending on the vehicle, different equipment is used:

- Air conditioning system with 1-zone temperature control

- Air conditioning system with 2-zone temperature control: splits the passenger compartment into two climate zones. Drivers and front passengers can select their own temperatures separately.

- Air conditioning system with 3-zone temperature control:

drivers, front passengers and passengers in the rear passenger compartment can adjust their own temperatures separately.

‘Air Care Climatronic’ air conditioning system with 2- or 3-zone temperature control

(An active biogenic filter also pretends fungal spores and tiny allergens from entering.)

Image of the air conditioning system in a VW Up!

Air Curtains

The term ‘air curtain’ refers to narrowing air inlets in the vehicle’s front bumper. The air inlets below the headlights ensure that the air is guided through the bumper and only re-emerges behind the wheel housing. The wheels are not affected. This improves the aerodynamics while increasing the surface pressure of the vehicle front end.

VW Golf R viewed from below at an angle, air curtains detail
Fuel consumption Golf R in l/100 km: urban 8.2-8.1 / extra-urban
6.6-6.5 / combined 7.2-7.1; CO₂ emissions combined, g/km: 164-162;
efficiency class: D

Air quality sensor  

The air quality sensor is part of Volkswagen's ‘Climatronic’ automatic air conditioning system. Its job is to detect harmful substances in fresh air which occur as oxidisable or reducible gases. Oxidisable gases include, for instance, carbon monoxide (CO), hydrocarbons (benzene or petrol vapours) or other fuel components which have not completely combusted. Nitrogen oxides (NOx) are reducible gases.

In poor-quality air, such as in traffic jams or when driving through a tunnel, the control system activates ‘Climatronic’ air recirculation and prevents the polluted fresh air from damaging the air quality in the vehicle interior.

See also:
Air conditioning system

View of a VW ‘Climatronic’ air conditioning system in a VW Polo

Air recirculation, automatic 

The air quality sensor is part of Volkswagen's ‘Climatronic’ automatic air conditioning system. Its job is to detect harmful substances in fresh air which occur as oxidisable or reducible gases. Oxidisable gases include, for instance, carbon monoxide (CO), hydrocarbons (benzene or petrol vapours) or other fuel components which have not completely combusted. Nitrogen oxides (NOx) are reducible gases.
In poor-quality air, such as in traffic jams or when driving through a tunnel, the control system activates ‘Climatronic’ air recirculation and prevents the polluted fresh air from damaging the air quality in the vehicle interior.

See also:
Air conditioning system

Image of Discover Media in the VW Arteon

Air suspension (CDC) 

Air suspension, or CDC (Continuous Damping Control), offers extraordinary driving comfort. Instead of conventional steel springs, it has rubber bellows filled with compressed air. Adapting the volume of air allows the system to adjust the height of the vehicle body. Volkswagen offers air suspension with continuous damping adjustment. Thanks to automatic adaptive suspension, the body is kept at a consistent level, irrespective of load level. Pitching movements which occur when braking or accelerating are offset. The air suspension and damping system improves driving and suspension comfort considerably.

Image of a Volkswagen air suspension system

All-wheel drive coupling  

The all-wheel drive coupling is an electronically controlled multi-plate clutch. In the permanent all-wheel drive 4MOTION, it enables variable distribution of drive force between the front and rear axle. Its seamless adjustment is controlled by a control unit that takes the slip – the driving dynamic situations and the driving torque – into account.
The all-wheel drive coupling control is built into the Electronic Stability Control system, contributing to vehicle safety.

See also:
Electronic Stability Control

Schematic diagram of the all-wheel drive coupling in a VW Golf R
Fuel consumption Golf R in l/100 km: urban 8.2-8.1 / extra-urban
6.6-6.5 / combined 7.2-7.1; CO₂ emissions combined, g/km: 164-162;
efficiency class: D

All-wheel steering

All-wheel steering mainly affects two driving conditions:

Driving condition 1: Up to 37 km/h, the rear wheels automatically turn at the opposite angle to the front wheels. If the front moves left, the electrically controlled rear axle turns at a steering angle of up to five degrees right. This improves manoeuvrability. The turning circle made smaller by the all-wheel steering is particularly noticeable when parking. This also makes it easier to manoeuvre with a trailer.
Driving condition 2: If the speed rises to over 37 km/h, the rear wheels turn in the same direction when steering – i.e. the same direction as the front wheels. This can make driving behaviour even smoother, particularly at country road and motorway speeds, as the all-wheel steering can stabilise lane changes*, such as during speedy overtaking. The same applies to sudden swerves.

* within the system’s limitations

Schematic diagram of all-wheel steering in a VW

Ambient lighting  

Ambient lighting illuminates the interior as required. Illuminated sill and decorative trims, reading lights in the front and back and footwell lighting can all create the customer's preferred atmosphere.
Cosy or bright – the lighting settings are easy to control using the central display. The interior lights are all equipped with advanced LED technology.

Ambient lighting in a VW Golf

Anti-lock brake system ABS  

When the vehicle brakes hard or travels on a slippery road surface, the anti-lock brake system can prevent the wheels from locking and maintain the vehicle's ability to be steered*.

* within the system’s limitations

Anti-lock brake system (ABS) indicator lamp in a Volkswagen

Anti-theft alarm  

The anti-theft alarm system with electronic immobiliser offers optimum protection from vehicle theft. Audio and visual warning signals draw the attention of passers-by and scare thieves away. In the event of unauthorised opening, it triggers an audio alarm through contacts on the doors and lids or ultrasound motion reports. The ultrasound sensor also picks up when people are trying to get into the vehicle through a broken window.
The new generation of anti-theft alarm includes a back-up horn which is not connected to the on-board power supply and a time-controlled alarm in the event of unauthorised door opening. Locking the vehicle activates the anti-theft alarm, while opening the vehicle switches it off. Depending on the model, Volkswagen vehicles also feature incline sensors as part of the anti-theft alarm system. They record changes in vehicle location (theft through removal) and raise the alarm. The anti-theft alarm offers an initial warning by means of a 30-second horn sound. The hazard warning lights then flash continuously.

A VW Golf from the side with a graphic safety lock over the roof


App-Connect displays selected smartphone apps on the touchscreen of the Infotainment system – for three innovative technologies: Apple CarPlayTM, Android AutoTM and MirrorLink®.

Discover media screen with Car Play on screen

‘Area View’ surround view camera

‘Area View’ supplies images of the area around the vehicle live to the cockpit. This gives the driver an outstanding view of their immediate surroundings. The system offers a range of angles and views to give the driver optimum assistance in every traffic situation.
Four cameras guarantee a panoramic view. With the 180° wide-angle lens in the front and rear, the driver’s field of vision is expanded by 90° to the left and right even from the front- and rearmost point of the vehicle. This makes it possible to see ‘around corners’, as it were. The system provides assistance with tricky manoeuvres such as attaching and manoeuvring with a trailer, driving off-road or merging in complex situations.
The camera images are digitally processed and shown in real time on the radio or radio navigation system display.

Schematic diagram of ‘Area View’ in the VW Arteon

AR head-up display  

The head-up display shows vehicle-related information in the windscreen in the driver’s immediate field of vision. Unlike static head-up displays, the Augmented Reality head-up display projects important information onto a second focal plane in the driver’s field of vision. By positioning the information directly on the road, the display blends seamlessly into the environment. It minimises diversions when driving and makes turning easier with optional navigation.

Augmented Reality

Augmented Reality is the superimposing of virtual information over real elements.

Auto Hold function  

Volkswagen's Auto Hold function is an extension of the electronic parking brake. It stops the vehicle from rolling away accidentally when at a standstill or starting without requiring permanent pressure on the brake. This means Auto Hold offers a high level of comfort when driving (and starting off).
The system runs via the ABS/ESC hydraulic unit. If the vehicle is braked to a standstill, Auto Hold saves the last brake pressure. The driver can take their foot off the brake pedal and all four wheel brakes will stay applied. If the ABS wheel speed sensors detect rolling, the brake torque is automatically increased until the vehicle is once again at a standstill. This may occur, for instance, if the driver brakes gently on an incline. When the driver accelerates again and releases the clutch with a manual gearbox, Auto Hold releases the brake again.
For safety reasons, a switch to the left of the gear lever must be used to reactivate the function.

See also:
Hill Start Assist
Anti-lock brake system (ABS)
Electronic Stability Control

Interior view of a VW Arteon, centre console detail

Automatic headlight range control  

Automatic headlight range control ensures optimum headlight settings and road illumination. It ensures a consistent headlight range and stops the vehicle from dazzling oncoming traffic. The system operates automatically and adapts the headlights’ angle of inclination to the current load level.
In automatic headlight range control, a distinction is made between two systems: static and dynamic solutions. While static systems offset the load from passengers and luggage, dynamic systems also correct the headlight setting when starting, accelerating and braking.

In the static system, the control unit processes signals from the electronic speedometer and ABS control unit as well as signals from incline sensors. This allows the system to distinguish whether the vehicle is at a standstill or driving steadily.
In dynamic headlight range control, the much more effective control unit also differentiates the change in speed signals (accelerating and braking). The control motor also has a higher adjustment speed, adjusting headlight range in split-seconds. If the vehicle is equipped with xenon light, automatic headlight range control is legally required.

Image of a Volkswagen’s left headlight

Automatic Post-Collision Braking System 

Almost a quarter of all accidents causing personal injury are multiple collisions. Volkswagen's Automatic Post-Collision Braking System can help avoid follow-on collisions or reduce their severity.

After a collision, and within the system’s limitations, the Automatic Post-Collision Braking System automatically makes a braking intervention before the driver can react. This can help reduce the severity of the accident and ideally prevent follow-on collisions.

The driver can take control of the vehicle again at any time.

Schematic diagram of the Automatic Post-Collision Braking System function

Automatic Rollover Support System 

The active Automatic Rollover Support System offers additional safety for occupants in the event of a vehicle rollover.
The Automatic Rollover Support System consists of two separate cartridges that are each fastened behind the rear seats using six link points between the double luggage compartment rear wall. Thanks to the efficient rod design and through-fixing, the Automatic Rollover Support System can withstand much higher forces than previous systems. When the crash sensors detect the risk of a potential rollover or impact (front, rear and side), the system is activated via the airbag control unit.
An unlocking system causes the release rods to tilt up by a maximum of 265 millimetres in 0.25 seconds. The rods are locked in their final position and secure all four seats together with the extremely rigid windscreen frame. If the convertible roof is closed, the Automatic Rollover Support System travels spring-loaded towards the convertible roof headliner. If there is no rollover, the brackets can be fitted back into the cartridges by hand. This helps avoid potential repair costs.


VW on the coast with extended Automatic Rollover Support System

Autonomous driving

Autonomous driving describes the independent and targeted driving of a vehicle in real traffic. The driver does not intervene.

Auxiliary heating and ventilation 

Auxiliary heating preheats the interior and keeps windows clear in winter. On hot days, the auxiliary heating works as auxiliary ventilation and blows fresh air from outside into the parked vehicle.
Heating duration and start time are easy to set in the instrument cluster using the steering column switch. As well as timer function activation, the auxiliary heating can also be switched on using the immediate heat button on the air conditioning system or the remote control (range of up to 600 metres).
Presetting in the instrument cluster determines whether the vehicle interior is heated or ventilated when the weather is warm outside. The auxiliary heater thus ensures a comfortable climate inside the vehicle before the journey has even begun, whatever the season.

See also:
Air conditioning system

A Volkswagen from the front

AUX-IN socket 

The AUX-IN socket allows an external audio source to be connected to the radio and radio navigation system. The audio source is operated via the connected device while the volume is adjusted via the radio or radio navigation system. 

AUX-IN is only available to order in conjunction with certain radio and radio navigation systems.

See also:
Radio navigation system
MEDIA-IN socket

Socket with AUX-IN connection in a Volkswagen