2005 Uplander LT, DIC "service ABS system". Code scan reveals C0040, C0041 any ideas? Wheel speed sensor or wiring?

 

I have assumed that it is a wheel speed sensor, cleaned all wiring connections I could see. Checked ohms resistance for all 4, checked continuity on wiring harness, inspected for damage. All good so far. Cleared trouble codes with scanner. Been about a week now, no ABS light or service abs system warning on the DIC. Hope that's it.

 

The ABS light continues to come on , throwing the same codes. Have changed both rear wheel hubs and abs sensors. Problem continues. About ready to add incendiary device and strike match!

 

Did you change the hubs and sensors or did a dealer/mechanic change them?

GM has had intermittent problems with the ABS wiring breaking at the wheels and they have a repair kit with new plugs that you can install. (Google your codes and explore the GM TSB's that you find).

If you keep throwing parts at an intermittent it can get real expensive, you may want to bite the bullet on this one and get a GM mechanic to fix/warranty the problem. Good luck.

 

It's weird some GM sites on the net say the C0040, C0041 is the right front ABS sensor. I'm using a new Innova 3160 scanner and they come up as rear abs sensor subfault.

I have updated the scanner on the website, so it's software is current. Hence changing the rear hubs. I notice that when I clear the codes the EBCM cycles for a few seconds. I'm not sure if this is normal or indicates a bad EBCM. The wreckers around here say they have sold some. As soon as I move the vehicle it throws the codes again.

I've spoke with the dealer, they were not forthcoming with info other than bring it in and we'll diagnose it. The parts manager did say it's usually electrical and he has yet to order in an EBCM.

The one thing I know for sure is this model of van sure does have it's share of gremlins. I've already had to replace all the pads, and rotors. It's only got 60K on it and the brakes were done at 50k and are vibrating again. We're also experiencing the dreaded sliding door problems too!

Thanks Papa bear you confirmed what I already knew, but didn't want to admit. I'll book it in for a dealer visit next week. Hopefully they can tell me which wiring harness is bad.

 

Went to dealer. Their scan indicated right front harness. Check abs sensors they must read 1100 ohms, and should produce 300 mv. They found internally broken wire on right front wheel speed sensor harness. Harness replaced, reset codes. Problem solved. Being prison fisted by the dealer $374.64. I hope this thread helps others, the harness was approx $90. anyone with a similar problem should be able fix it themselves and change the harness.

 

Thanks for the update.

 

Is the 300mv you mentioned above supposed to be p-p (peak to peak, as read from an oscilloscope), or rms (root-mean-square or "effective voltage") as read from a regular DMM handheld tester?

 

i have a 2006 monte carlo ss. how do i check the harness for the right front wheel sensor? i have replaced the bearing and i am still getting the c0040 code.

 

fscoles I'm not sure as the dealer tested it and I was not present, I want to say RMS with a digital multi meter. Hopefully one of the site GURU's will chime in.