Drivers Information (ASR)
General
There are displays with various symbols for the ASR in the instrument cluster.
Switching On Ignition And Starting Engine
When the ignition is switched on (ignition/starter switch position "2"), the warning and indicator lamps come on in the instrument cluster (bulb check) and go out when the engine is running.
Driving Mode
In driving mode, the warning lamp flashes as soon as the ASR works. It provides information on the Acceleration Slip Regulation (ASR) control mode and warns the driver that he has approached the physical driving limits of his vehicle.
Driving style can thus be better adapted to the road conditions.
The warning lamp continues to flash for approx. 1 sec. at the end of ASR control mode. The warning lamp does not come on during very brief ASR control mode.
Malfunction Indicator Lamp Evaluation
Vehicles Without Brake Assist System (BAS)
If the ASR malfunction indicator lamp comes on when the engine is running, there is a fault in the networking of the ASR system and respective injection and ignition system. ASR is inoperative and the ABS function is retained.
It is possible to continue driving with reduced engine power (accelerator changes over to emergency running mode) if there is a fault in the Electronic Accelerator (EA).
If the ABS and ASR Malfunction Indicator Light (MIL) come on when the engine is running, there is a fault which affects both control circuits and both systems are switched off.
The fault is stored in the respective control module and can be read out using the Hand-Held Tester (refer to Testing and Inspection).
Vehicles With BAS
If the BAS/ASR MIL comes on when the engine is running, there is a fault in the networking of the ASR, engine control and BAS systems. ASR or BAS is inoperative. The fault may be in the BAS or in the ASR. In the first case, ASR is retained and in the second case the BAS function is retained. The ABS function is retained in any case.
It is possible to continue driving with reduced engine power (accelerator changes over to emergency running mode) if there is a fault in the electronic accelerator.
If the ABS and BAS/ASR MIL come on when the engine is running, there is a fault which affects the ABS and ASR control circuits and both systems are switched off. The BAS function can be retained.
The fault is stored in the respective control module and can be read out using the Hand-Held Tester (refer to Testing and Inspection).
ASR OFF Switch (S76/5)
In deep snow and when chains are fitted the sensitive, stability-orientated ASR control can impair the starting-off characteristics.
The ASR can be switched off in such cases. The drive moment control circuit is then no longer active, Brake intervention on one side can be effective while starting off up to a speed of 40 km/h. When the ASR OFF switch is operated, the warning lamp in the speedometer comes on permanently. This is to remind the driver that the ASR is switched off. If one or both drive wheels spin, the warning lamp flashes. This applies to the entire speed range.