My traction control warning light comes on intermittently when the car first starts. After it's warm and running, the problem goes away until the car sits and cools down again. It's not related at all to key cycles.

Is this the TCM, or something else entirely? I ask because of the apparent relationship to engine temperature. Also, if it is the TCM, where is it located, and is this an easy DIY replacement? It looks like about a $200 part new, and I don't care to get electronics from the boneyard.

 

Oh, and the ABS light doesn't come on at all.

 

Before looking to replace any parts, I would see if you can find someone with a GM Tech II that can read the codes from the EBCM (ABS computer). Most scan tools only read codes from the PCM, the GM Tech II can read codes from all the car computers, I believe so can some other higher grade scan devices (like Snap-On).

If you can get the code, most likely GM has some diagnostics that can be done to isolate what is wrong.

 

It is weird that you get traction control and not ABS, which leads me to think it might be a sensor fault, but not enough to trip the ABS light too.

I second the idea of getting it read to see what sensor is throwing the car for a loop. If it was the wiring harness to the tires, it should throw every light at you.

 

FYI, this seems to have been a foreshadowing of the misfire on cylinder 1. It hasn't reoccurred since I changed the plug.