Brake Assist (BAS) Drivers Information

Legend
A1 Instrument Cluster
A1e17 ABS MIL
A1e39 BAS Malfunction Indicator Lamp
A1e47 BAS/ESP Malfunction Indicator Lamp
A1e48 BAS/ASR Malfunction Indicator Lamp
A1e49 BAS/ETS Malfunction Indicator Lamp

Note:
For BAS a system malfunction indicator lamp is located in the instrument duster. On vehicles with ETS, ASR or ESP this is combined with the malfunction indicator lamp of the respective traction system

Switching on the Ignition and starting the engine
When the ignition is switched on (Ignition/starter switch in position "2"), the malfunction indicator lamp in the instrument cluster (bulb check) comes on and goes out when the engine is running. If the BAS malfunction indicator lamp comes on when the engine is running, there is a fault in the BAS. The system is inoperative but the full braking effect with ABS is retained. With the combined malfunction indicator lamp (BAS/ETS, BAS/ASR, BAS/ESP), the fault may be in the BAS or in the traction system. In the first case, ETS, ASR or ESP is retained and in the second case the BAS function is retained.

On vehicles with BAS integrated in the ESP, ESP is also inoperative if there is a fault in BAS.

Driving Mode
System faults which occur while driving also result in the BAS malfunction indicator lamp coming on permanently.
If the BAS malfunction indicator lamp comes on while driving and goes out after a while, the cause is low battery voltage.