Lmm u0101 tcm

[duramax0001]

Hey guys, I am need of some help diagnosing my TCM.

I have some pretty standard symptoms, a U0101 code (loss of comm with TCM), ABS light on, E Brake light on, no indicator under gear selection symbols, and I am stuck in what feels like third gear.

I haven't been able to find any issues yet, but here are the things I have checked.

-Grounds G102 and G103 cleaned and reconnected
-Harnesses removed, cleaned and replaced for the TCM and ECM
-Continuity confirmed between pins 9/69 and 10/70 in TCM
-0V confirmed at pins 9 and 69 in TCM harness
-12V confirmed at pins 10 and 70 in TCM harness
-I tried visually inspecting for shorted/open wires, but it seems futile with so many wires around the TCM/ECM

Is there anything else I could try? Is there a way to check for a faulty TCM without blindly replacing it?

Any help would be greatly appreciated.

 

[TheBac]

While you've given a good diagnostic list, you havent stated what year LMM, nor any list of mods or add-ons that might affect operations, is trans built or stock, etc.
I realize your frustration, but the more info you initially give, the more likely you'll get some help figuring it all out.

 

[Mike L.]

You need a TCM. Seems like I'm replacing one every month with your symptoms.

 

[duramax0001]

My apologies for leaving out my truck's info.
It is a bone stock 2009. The previous owner did install an intake and cat back exhaust though.

Thanks for the input Mike. I also assumed a bad TCM, but I would really like to confirm it somehow. Looks like I may just need to bite the bullet and get one though.

 

[Mike L.]

Unfortunately the only way to diagnose any computer is to install a know good one. You are on the right track my friend.