ASC + T system (Automatische-Stabilitats-Control plus Traktion) prevents the rear wheels from spinning when the accelerator pedal is depressed, for example when driving on wet surfaces. A spinning wheel transmits less traction and slip force. The system control is integrated into the ABS control unit. The control unit determines the instantaneous values of the wheel speeds using sensors located at the wheels, the signals of which are also used by the ABS. If one rear wheel is prone to slipping, the ABS/ASC+T control unit sends this information to the DME digital engine control unit (Digitale-Motor-Elektronik). Based on this information, the DME, by influencing the duration of fuel injection by the injectors, changes the engine power, in addition, the fuel injection advance angle can be changed. Such regulation has an effect similar to that which occurs when the driver takes his foot off the accelerator pedal. Engine power declines rapidly and the wheels can now effectively interact with the road surface. If this does not happen, then the T function is activated (traction control), and the slipping drive wheel is metered slowed down. The driver will recognize the activation of the T function by the flashing of the indicator on the instrument panel.
The system is endowed with the ability to control the engine torque. It prevents short-term blocking of the drive wheels on slippery surfaces by braking the engine crankshaft. At vehicle speeds up to 40 km/h, the traction control system can act as a differential lock. Since the left and right wheels brake independently, the ASC+T system acts like a locking differential with close to 100% efficiency.
The ASC+T system independently detects faults that occur. After the ignition is switched on, the warning lamp on the instrument panel lights up for a short time and then goes out. If the indicator does not go out or stays on during the trip, this indicates a malfunction. You can continue driving, but the ASC + T system will not work.
When driving with snow chains, in deep snow or when starting out of deep mud, it is advisable to switch off the ASC + T system using the switch located on the center console. When the switch is pressed again or the next time the engine is started, the system turns on automatically.