I have had it at 5 different shops including dealership and nobody can figure it out.That is a bit steep for sure, but third, what the hell is going on with your car?
The big issue is c121c. That’s the code they can’t figure out.And 2 different tuners.
I’m going through all of the wires right nowThe big issue is c121c. That’s the code they can’t figure out.
ABS module checked?I’m going through all of the wires right now
I will check all of that out. I really appreciate your help thank you hopefully I’ll find the gremlin.While you're at it, yaw rate sensor might also be failing or become loose. Wheel speed sensors should throw their own codes, so they are unlikely but still possible point of failure...
As for the wiring harnesses, they are, as you prolly know by now a bitch to check. Especially if the problem is intermittent.
Check all the connector pins (especially on modules) with a magnifying thingy for signs of sparkin. IIRC older GC models had a habit of arcing in the connectors.
I wasn’t going to go there but 100% agree.Highly unlikely you have 3 failed ECMs. How was it determined they were failed?
I agree I have to go through it with a fine tooth comb.If the ECMs were in fact all toast, there most likely is either a bad intermittent ground or a chafed wire pair in the loom that spikes voltage into wrong pin. Or, last guess, the TIPM is effed up and burns the ECM.