4.8is: 2 speed sensors replaced, one in rear is not registering...still throwing code

[Porschesolutions]

My X5 lost the alternator and in the midst I now have two dead speed sensors on the driver's side, causing all sorts of DSC/ABS codes & sometimes jerking the steering wheel around when a sensor mis-reads.

Had both sensors replaced by my independent...new sensors testing out good, but the rear is still not registering and throwing codes... Any suggestions??

Mechanic said the teeth appeared good/none missing in the rear...but still sensor not registering.

[TerminatorX5]

not registering? the signal from the sensor is not read at the ABS module?

put the diode meter onto the plug at the ABS module (i don't remember the pinout, but it is available both on xoutpost and bimmerforums), and see if the sensor is reporting to the ABS module - you might have a break in the wiring going from the wheel to the front of the car

[upallnight]

Did you use original BMW wheel sensors or at the very least O'Reilly's life time warranty wheel sensors?

Are you getting a signal to the ABS Computer? Did you inspect the wheel sensor mounting and air gap?

https://www.youtube.com/watch?v=Sd-duZ2RCKA

Another Youtube video with a shorted harness wire to the wheel sensor.

https://www.youtube.com/watch?v=bPdPhGcZOe0

[Porschesolutions]

I assume they came from WorldPac as my independent did it. If their code reader shows the proper codes & the front sensor cleared the code for the front, the rear is just not clearing the code for the rear. :/

I know the air gap/teeth were observed but it's my understanding that there is no adjustment to be made at the mounting point.

Mark

[upallnight]

No adjustment, but if the mounting surface wasn't clean it could cause enough of a difference so that the wheel sensor is not picking up on the tone ring movement.

[Big "J"]

Hey Mark!

The Texas heat will cause all kinds of issues with our ABS/ DSC modules in the engine bay. I replaced mine last winter after going through similar issues last Fall. The module has hair thin wires that can degrade and break from the heat causing communication issues as well.

Good luck!

[Porschesolutions]

Whaaa? Preposterous...it's only 104d today

Thanks, I'll look into that too...probably the easiest thing to do is to try another DSC/ABS unit and see if that clarifies things...I'm wondering (too) if the 17v spikes from my alternator may have caused a short somewhere.

Is the DSC/ABS module easy to find?

Mark

[Big "J"]

LMAO!! I read 106 deg in my truck going home yesterday. Its directly under the power steering resevior and sits behind driver side headlight. Like with most things in the engine bay, you have to remove half of the top side components to get to it and then hire a dwarf with small hands to unbolt, take it out and put it in.
I found mine on ebay, new Bosch 8.0 module for about $525. A new module will need to be programmed and coded to your truck. If you have GT1 or similar, knock it out no biggy.
I called up Okee "Triple O coding" and he tapped in remotely on my laptop (I have the USB/ OBDII connector) and got it set up. While in there he updated the tranny, transfer case and DME modules to the latest and greatest versions using winkfp.

[Porschesolutions]

Ok good to know....thanks again!