The Anti-lock Braking System (ABS) is one of the most important innovations in car safety. It allows for the maximum traction under braking to prevent skidding and loss of car control. In a high performance car like the BMW, the BMW ABS system is a crucial part of the cars safety features and BMW ABS warning lights and problems should never be ignored. Because to the important role of the BMW ABS system, getting the inputs and insights of Experts on repairs, adjustments and replacements is the best way to ensure that the work is done correctly. Read below where questions have been answered by the Experts.
There is a BMW service bulletin that covers the problem this owner seems to be facing. This is what is says:
ABS/DCS - Warning Lamp ON/Code 30 or 31 Set
SI B34 04 05
Brakes June 2005
This Service Information bulletin supersedes Service Measure B34 201 03 dated June 2004.
SUBJECT - Rear Wheel Speed Sensor Corrosion, Fault Code 30 (1e) or (1f) MODEL E53 (X5)
SITUATION - ABS/DSC Light On with Rear Wheel Speed Sensor Fault Code 30 (1e) or 31 (1f)
CAUSE - Corrosion in Rear Wheel Speed Sensor connectors
CORRECTION - Check Rear Wheel Speed Sensor Connectors for any corrosion.
This is a not uncommon BMW ABS problem. The cause is a problem with the ABS module. The BMW ABS sensor may have failed and damaged the circuit board on the module. The problem can get worse when the car heats up as the bad weld in the module opens up and the false loss of wheel speed is detected. The BMW ABS system will need to be replaced and programmed and the sensors will have to be calibrated.
If the BMW ABS light is still on after the repairs were done then it is probable that there still is a problem with the BMW ABS system or that a failure has occurred in the instrument cluster. BMW ABS module failures are more common than cluster failures so that is the first thing to look at. However, before doing that try to reset the system by disconnecting the battery for an hour and seeing if the light has gone out when reconnecting it.
If the BMW ABS light is always on but the steering wheel shake is only at a specific speed it seems that there are two unconnected issues. The reason for the ABS light being on could be a failed BMW ABS control module or a defective wheel speed sensor. The best way to find the cause is the have a fault readout done using a BMW scan tool. The shake in the steering wheel is likely to be caused by a sticking brake caliper, worn out front end bushings/suspension or wheel bearing/hubs. Other causes could be a bent rim or a warped brake rotor.
The failure or improper functioning of the BMW ABS system can lead to loss of car control and be a major safety concern. When BMW ABS warning light comes on or there are other indications of BMW ABS problems, the issues should be attended to immediately. Getting the guidance of and answers from Experts is the way to ensure that repairs are done in the right way and that safety is not risked.