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

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.

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

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:

What's wrong with my BMW? The ABS and traction control lights are on.?norton 2008

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.
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.
Crankshaft sensor? He's clueless.