kevlar129bp

Hello all,

I have to admit, I have been lurking here for quite some time due to my Cobalt woes. I have a 2006 2.4 SS and a 2006 2.2 LS. The SS had some issues regarding the traction control that was fixed with the TCM ground mod. Thanks guys . The LS had similar issues, only worse! As the thread title suggests, I had a complete loss of communication with the TCM. Of course, my first thought was, I'll ground that b*tch and she'll be good. Well, no love there. I proceeded to clean ALL the connectors at the BCM, TCM and ECM with spray contact cleaner and compressed air. No love there either. From there, I took it to the dealer (VERY AGAINST MY RELIGION!) where the service wrighter told me it would be $125 (all in) to run a "25 point" diagnostic check on the problem. Keep in mind that, of course, he acted like this was the first time he had heard of the Cobalt issue in his career! Yeah right! Anyhow, they did their dog and pony show. The service writer called my wife and told her there is a "frayed" wire causing the TCM to "have a short", causing it to not have power.

Not to get off on a tangent, I must admit that I install and service commercial and industrial security and fire alarms for a living. When we talk about "shorts", we must also talk about "WIDE OPENS"! Usually when one experiences a short, we blow fuses, or worse, start fires! When one experiences an open, neither happens! THERE IS NO LOAD TO BLOW THE FUSE! Please, please, please, to anyone who will listen, NOT ALL WIRING ISSUES ARE SHORTS!

I know what your probably thinking right now...If he does low voltage systems for a living, why didn't the dumb*ss test for voltage before he took it to the dealer? Great question. One, I didn't find the schematics until the day after I had it at the dealer and two, maybe my frustration of dick*ng with it. (BTW: schematics were found on this site! Kudos to the chef! Thank you, thank you, thank you! )

Back on topic, so the dealer wanted to nick me $400 to "find the short". I promptly and respectfully declined! Upon getting the 'balt home, I dug in. With schematics in hand, bingo, no constant power at the TCM! Who woulda thunk. I ripped the fuse box apart under the hood and located terminal "A2". I then dismantled the TCM plug and located pin 32. I tested for continuity between the two and yep, WIDE OPEN. I proceeded to peel off the split loom tubing that covered the harness leading from the TCM to the terminal block that resides under the fuse block. I was then able to expose the entire length of the red/white wire in question. To my surprise, there was a ding in the jacket of the wire which caused it to corrode in half! It was very difficult to see at first. At that point I figured, what are the odds, let's fix it and see what happens. Well, here I am. No MIL, speedo works, transmission shifts, etc.

After reading so many forums and posts relating to the same issues I have had, I felt compelled to share my experience with you fine folks. I sure hope it helps someone with their frustrations.

I have included some photos just for reference.

Thanks all,
Chris

JErlewine

I have this exact same problem with my 2007.. Did the grounds. Did the pinset plug clean up and reset. Yeah every song-and-dance I could find on the Internet. Even bought a brand new programmed to my Vin number TCM. Nothing. I feel the problem with these forums is everybody talks about the problems they're having and there are multiple multiple people with the same problems. The issue is when somebody fixes their car they never get back on here and let the rest of us know what actually worked.... You my friend are a gentleman and a scholar. I'm going to go home and try this and I thank you very much.