Transmission control module questions

[Paulpren]

I've got a M1097A2 hmmwv. A transmission shop said I've got power to my TCM however no power going to my transmission; so in limited to be stuck into 2nd, meaning no shifting. I'm thinking my TCM is bad? Not sure but the transmission shop said it should be replaced. Need assistance on where to get one. The number on mine is 16196390. And it's got a blue chip set in it. Whatever help anyone has would be so awesome. TY!

 

[NDT]

Hello and welcome. This issue comes up a lot and most of the time, the TCM is not the problem. Wiring in and around the battery box is. Here is a thread that contains the 4L80E bible for HMMWVs, "supplement 7"

M1123 transmission | SteelSoldiers

 

[Paulpren]

Hello and welcome. This issue comes up a lot and most of the time, the TCM is not the problem. Wiring in and around the battery box is. Here is a thread that contains the 4L80E bible for HMMWVs, "supplement 7"

M1123 transmission | SteelSoldiers

Thank you for your response. New at this site and not sure how to find the TCM related articles. I've checked the lead wire in battery box that powers the tranmission and it's at 12v. Not sure where to go now for help or what to check next... Thank you.

 

[NDT]

Did you click on the link, go to post 8, open supplement 7, and read page 49 about the 12 and 24 volt circuitry that is needed for the TCM to come to life?

 

[Paulpren]

Did you click on the link, go to post 8, open supplement 7, and read page 49 about the 12 and 24 volt circuitry that is needed for the TCM to come to life?

No I haven't please explain.

 

[NDT]

Follow steps pictured.

 

[TOBASH]

Super easy. Trust in the force Luke.

The TM a goes over tranny function and troubleshooting in painfully detailed descriptions with pictures and arrows.

Initially seems daunting. It isn’t. Just simple grunt work with a few protocols to follow.

You will be OK.

 

[mrfarb]

I went through this. Since you have it at a shop and aren’t working on it yourself, you are at their mercy. I guess you start throwing money at it if you trust them. But me, I followed the tm troubleshooting myself and fixed mine. Relay turned out to be bad. TM for the win.