My truck went into Chevy dealership 2 weeks ago, truck was acting up; check engine light coming on intermittanly, would not turn over, service 4 wheel drive message popped up, intermittant stalling. Was supposedly fixed, with diagnosis of my wiring harness was rubbing against master cylinder. Truck is in again today with check engine light on, and would not turn over last night....but no other issues. Took it in this morning, they said that my TCM is completely busted, and they are trying to see what else could be the issue. Is this a big problem, and what would I be looking at for cost to repair? I have no idea how something like that could get so busted up, as i am not hard on my truck, and I have not been driving anywhere! Was this not something they would have seen so broken 2 weeks ago when my truck was in for some of the same issues? Anybody have any answers that could help me? It would be greatly appreciated!!

 

Pure speculation here, but if this TCM is a "traction control module" then it will be expensive. If they repaired the wiring harness by the master cylinder, then no, they wouldn't necessarily know that the TCM is dead. If they replaced the harness, like I assume a dealership would try to do if the problem is complex, then yes they probably would have definitely noticed.

The module could have been shorted by the damaged wiring harness. I'm guessing it's possible that they could have noticed it if they were doing a check with a scan tool, but if they just repaired the wiring harness and sent it back to you, then maybe not ...

I have no clue on a price ... but if a module is damaged, they will replace it. There's no repairing an electronic module.