BMW (ABS) Diagnostics

The Antilock Brake System (ABS) control unit continueously monitors the system electronics and wiring harness for possible defects. The system must be checked if:

- The ABS indicator lamp does not illuminate when the ignition is turned "On"
- Extinguish after the brief test
- Illuminates while driving

When a fault is detected, the ABS indicator lamp will illuminate to notify the driver of a system malfunction and the ABS control unit will shut down the anti-lock function, "fail safe", assuring normal use of the conventional brake system. The ABS system will not resume standby mode until the related malfunction is corrected.

NOTE:
If the ABS warning lamp remains "On", then a fault is indicated. Only after the fault has been repaired, will the lamp go "Out". There is NO procedure for turning the lamp "Off".

When testing the anti-lock brake system, ensure all other electrical components are turned "Off", and that the ignition switch is in the "Off" position before connecting diagnostic equipment.