2007 Monte Carlo SS, sorry for the video format this was taken off Snapchat 🫡
I’ve been toying around with an intermittent electrical ghost which would trigger the door locks to go off and the entire electrical system to go haywire.
A couple days ago, every dash instrument went dead and I had to park the car since it put itself into limp mode. After some diagnosing, I got a code saying the car had lost comm. With the TCM, and I can get it to replicate the issue consistently by wiggling the TCM wiring harness.
What I have managed to find is that whenever the TCM casing is connected to a ground (what you see me doing in the video, it’s a multimeter lead on a chassis ground) I will have full communication with the TCM and read all of its live data with my scanner.
I tested for continuity between the connector and all of the grounds and negative terminal which all passed. Both GMLAN +/- l’s on the TCM are receiving .5V / .8V on the two respective Communication wires, but they are only receiving (I’m not sure if this is an issue or not).
If anyone has any help on this I’d greatly appreciate it. I think I’ve gone as far as I can with the tools I have available but I’m willing to dig a little deeper if anyone has advice.