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2006 GMC Sierra 1500 - ONStar reports

I have a 2006 GMC Sierra and I receive ONSTAR reports indicating I have an issue with the traction control system diagnostic code C0055. When I took it to the dealer it was showing no code and no light, never showed an instrument light. Service writer basically said no light no code should be no problem. This has been going on for 4 months now , I have no issues while driving, is there something else I can check to eliminate the ONSTAR issue?

That code is for a rear wheel speed sensor. It means your ABS may mot be working correctly. I don’t know how that system works but normally if the check engine light comes on there’s a code stored even if the light doesn’t come on again. Have another dealer or an independent shop check for a stored code.

It might also be a dirty sensor or dirty/corroded contacts in the electrical connectors. I had intermittent codes on the wheel sensors on my 2003 Olds Silhouette. I opened the connectors and found they were corroded. After cleaning them, the CEL never came back. It might not work, but it’s an inexpensive fix if you do it yourself.

A common problem on chevies of this vintage is rust forming under the mounting flange for the abs sensor. It lifts the sensor enough (a few thousandths is enough) to cause loss of signal. It starts out very intermittent and gradually gets worse. You can verify signal dropout with a moderately priced scanner, driving while monitoring their signals. Many just replace the hub but I fixed mine by removing the sensors, cleaning up the rust and reinstalling.