"BMW - Brake, DSC and ABS Lights On"

By Ron Stultz

22 February 2011

Summary: when the brake, dynamic stability control (DSC) and antilock brakes (ABS) lights are all on at the same time and never go out, either repair do-it-yourself (DIY) or have it done, as soon as possible. Depending on failure mode, the ABS may be trying to "kick on" all the time with resulting wear on brake pads and tires.

Background:

BMW X5, 4.4, model year 2000, 145,000 miles as of this date.

Brake, DSC and ABS lights came on. Initially would be out when car started but after 10 miles or so, all would come on again.

Hooked Autoenginuity personal computer (PC)-based scanner to X5 and appeared that there was a failed driver's side wheel speed sensor. Bought sensor and installed. No change. Autoenginuity also reported several DSC\ABS errors it could not identify.

For your information (FYI), if attempt to DIY, must have a scanner capable of reading the CANbus. An ordinary on-board diagnostic (OBDII) scanner will not see the DSC\ABS unit. And if you a mind to, you can buy a junkyard DSC unit for about $300.

Internet search revealed that most likely cause of error light trifecta was failed DSC unit and replace cost about $2000 United States dollars (USD). Not happy.

Internet search revealed that with brake, DSC and ABS lights on, would not have DSC or ABS but figured I could live with that or for a least a while until I was ready to take to dealership or other and potentially face $2K USD outlay.

Do not delay in having repaired:

Ok, so no DSC\ABS, I could live with that or at least for a while. Well a while stretched too long.

In my case, and I did not know this until finally got unit replaced, the DSC\ABS failure mode was such that the ABS was always trying to click on and it was constantly pulsing brake pressure which resulted in excessive brake pad wear and also tire wear as brakes were not being pulsed equally on both calipers.

So lesson learned.

If your brake, DSC and ABS light are on, get it repaired. Don't add to your repair cost by having to replace brake pads and potentially the tires.