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      12-15-2012, 01:07 PM   #20
Enlisted Member

Drives: '09 E92 M3
Join Date: Sep 2012
Location: Bay Area, California

iTrader: (0)

Hey guys, I have a related question. Let me know if you have any experience with my issue.

I have an e92 M3, and was at Thunderhill a few weekends ago for some track action. Early on the second day, while waiting in the pit to get on the track, I had several warning lights come on:

* Bracking/chassis stablization malfunction!
* DBC malfunction! Drive carefully
* Start-off assistance inactive!

I went to Dinan to have them diagnos the problem. The tech reported that "the rear pulse generator/wheel bearing assy. was defective." So I ordered a new pulse generator from (about half of what BMW would charge!). It'll be here in a few days.

Yesterday, I pulled the wheels off and inspected both rear pulse generators. They had a lot of debris on them. They otherwise looked intact, although it looked like the one on the left had been rubbing slightly against something. I cleaned them off, and then reinstalled. I am still getting the same warning lights.

My question is this. Is the pulse generator somewhat like the brake pad sensors, in that when they come into contact with something, that is an indication that the wheel bearing is in need of replacement? I'd probably do the wheel bearing replacement myself, but in reading this post, I am a little concerned that it might be tough. I also don't want to put on the pulse generator, and have contact something and go bad again.

There is another post (, which seems to suggest that the sensors just wear out, and are unrelated to wear on the wheel bearing.

BTW, my car has about 67000 miles (mostly freeway) and I am not noticing any noise from the wheel bearings.