ABS and ASC light on BMW – what does it mean and how to fix it?

BMW driver question

I have a problem with my BMW, namely the ABS and ASC are not working. I read that it may be a sensor in some wheel. And here I have a question, how long does it take to diagnose at BM Cars and what is the cost?

The question is about BMW X3 E83, but it may occur in other models as well.

Response from BM Cars service

Signaling ABS problems, i.e., the ABS light illuminating permanently or intermittently, can be caused by a number of defects related to the functioning of the ABS and ASC systems. Most often, the damage is caused by a malfunctioning ABS sensor.

There is a sensor in each wheel that measures the speed of the wheel while driving. Impulses from the measurement are transmitted to the ABS controller, which activates the ABS system when braking, and in the case of the ASC or ASC T system, also to the engine controller, which corrects the increase in engine speed to prevent skidding when starting or driving on slippery surfaces. This applies to vehicles with four-wheel drive (X-Drive).

In addition, signals from the sensors are transmitted to the transmission controller, which temporarily engages or disengages front-wheel drive. A malfunction in any of the four sensors results in ABS and ASC error signals and can cause the system to shut down.

Another cause could be damage to the wiring between the sensors and the ABS unit, the unit itself, or the bearing/hub raceway from which the sensors read wheel speed.

A full system diagnosis is required to fix the fault. After this diagnosis, we can determine the cost and time of repair.

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