What's wrong with my BMW? The ABS and traction control lights are on.?

Question

My 2000 BMW 528iT has a big problem. It started with the ABS and "Traction Control" warning lights came ON. Then I noticed the speedomoter started to work part time only. It works mostly when the car is cold. Then it may stop after a few minutes of driving. However, it may work again at any time with no reason. The "check engine" light also came ON and OFF but not sync. with the stop and go speedometer.

My mechanic tried to change the "Cranshaft Sensor" and did not fix the problem. Then he changed the 4 ABS Speed Sensors (one on each wheel). The problem is still there.

What is the real cause of the problems?

Please help.

Answer 1

Most likely, it's the DSC Controller. It's a $900 part, unfortunately. I had to replace mine on my 1999 540i. Very similar symptoms to yours.

PS: Ignore the Beemer haters. They're just jealous.

Here's some helpful sites to search:

Answer 2

Your mechanic is right. The ABS and DSC use the ABS speed sensors - that would be my first guess as well. It still makes the most sense, especially given the problems you're having with your speedometer. DSC does control the ABS system, and DSC also uses a yaw-meter and gyroscope to determine skids, so those are other points of failure for both systems. However, given the speedo problems, the ABS sensors seem the most likely culprit. Given that he's changed them, it could be in the wiring - I would see if he can determine which sensor is failing (the speedo should only use one of the four).

The other possibility is a faulty ground in that circuit, but that's only really likely if you had electronic work (even something like a new stereo) done recently. If you did, have them go back over the wires and see if there's a ground they forgot to replace.

Good luck.

Answer 3

That's gotta be disappointing. I don't know for sure but I did look online in the parts catalog for a speed sensor for the speedometer as I am not totally convinced that the abs speed sensor does the same job. I did not find one, but that doesn't really mean it doesn't exist. If not, then its probably a bad connection to a sensor somewhere and might turn out to be in the ecm. You might try a reset if you have not. There are some pretty good BMW forums. I found some on Google when I was having problems.
Sorry, not much real help, but I do feel my answer is better than SOME you got.

Answer 4

Crankshaft sensor? He's clueless.

Check your owners manual and look for the diagram regarding "relays." See if the same relay supports both the ABS and Traction Control. If so, remove it and have it tested. It's probably the cause.

If not, chances are both relays woud not fail at the same time. I would suspect something "higher on the food chain" as they say.

Perhaps it's the on board computer. It might also explain why the speedometer comes and goes.

If your check engine light comes and goes as well, why not take it to a qualified BMW mechanic. He has a tool that he can hook up to your engine and it will tell him a code that he can look up and figure out what's wrong.

A qualified BMW mechanic can troubleshoot your problem quickly and painlessly.

Answer 5

When the Traction Control light comes on in my bmw, there are two reasons. I turned Traction control off or im sliding in some way and the traction control is working to fix it.

Answer 6

Traction Control Light Bmw

Answer 7

abs can be a problem, u need a mechanic to put his computer on the car to find the problem. Once he hooks a computer to it it will anzalize the problem and you can find out what is wrong.

Answer 8

BMW's are meant for wealthy people, stick with your mechanic, he will figure it out, quit trying to get free advice from poor people.

Answer 9

Trade in your Nazi Hitler machine on something else.