Tcm??

[Skyhigh4by]

Still trying to diagnose my u0101. So far at the TCM connector I have confirmed 12v constant, 12v ignition source and both grounds. The serial data wire is good to the DLC, the CAN LO and CAN HI wires are good to the ECM. All my other ground connections are clean and solid. Tow haul mode and OD lockout both function on the dash. T-case will go in to 4HI but won't go in to 4LO. Batteries are fully charged and good. I disconnected/inspected/reconnected every plug at the underhood fuse panel.

I don't know what else to do besides try a new TCM. Idea please??? Been this way for a few weeks now.

 

[Lparrill]

Could you find someone close that would let you borrow their TCM to try?

 

[02greysixer]

I'll have a known perfect lly tcm by this weekend hopefully if you end up needing one. Nothing wrong with it. Just don't need it with my zf swap

 

[onebaddmaxxx]

I would unwrap the harness 12" from the tcm connectors and look for corrosion. Can you communicate with the tcm at all? I would assume no but figured its worth asking. Any drivability issues?

 

[Mike L.]

Have you checked if the TCM is communicating with the trans?

 

[Skyhigh4by]

If I were to try another TCM would any reprogramming need to be done as long as it cam from another 4x4 5spd?

I have had the harness out and unwrapped from TCM plugs to under hood fuse block and also from there back to trans to inspect it. Couldn't visually see damage.

I havent checked to confirm whether TCM is communicating with trans. Any specific wires I should check or particular things I should look for when doing that?

Im using ALLDATA for as much info as I can.

 

[onebaddmaxxx]

Try taking a scan tool and talking to the tcm. Try reading codes or data

 

[Skyhigh4by]

It's code u0101. The TCM won't communicate

 

[Skyhigh4by]

I have a working TCM from a 2003. Can I just try it without having to reprogram or anything?? What I actually want to do is try my TCM in the 03 to see if it has the same symptoms or not.

 

[02greysixer]

Even if it doesn't work correctly or needs programmed you should still be able to see a problem by swapping tcm's if indeed it is a bad tcm. Because you have to be able to communicate with the module to program it. So if you swap your 05tcm to the 03 and now you can't communicate with your tcm in the 03 then you know there's a problem with the tcm. You can verify even more if you put the 03 tcm in the 05 and it communicates.

 

[Skyhigh4by]

Unfortunatly Im not going to have a scan tool to use when I try swapping them. Just gonna do it in my spare time at work with a company truck.

An observation I have made in all of my testing/diagnosing is that it makes no difference whatsoever if the TCM is plugged in or not when I start/drive the truck.