Archived No overdrive or TC lockup

[Got HO?]

This is driving me nuts!

I have a code P0123 (throttle position sensor voltage too high) code, transmission won't upshift into 4th gear & TC lockup is inoperative. Have replaced the following items:

Governor pressure sensor (transducer) & solenoid.

1/2, 3/4 shift solenoid pack.

Throttle position sensor.

Checked and cleaned all plug connectors on transmission & ECM's.



This is a hard fault that will appear just with the key turned on after erasing the code. Don't have to start the truck.

Has anyone run across this problem? I have a feeling that it may be harness related or a possible PCM :{

 

[tp0d]

Definetly run down the entire length of that wire for any rub points. Also check any grounds that the PCM uses. Have you cleaned your battery terminals yet?



Hmm strange problem. .



good luck



-j

 

[Got HO?]

After lots of time spent looking at wiring diagrams & checking connectors etc, it looks like I may have a bad ECM. I have continuity from the TPS to the ECM, and continuity from the output side of the ECM to the PCM so the harness is good. Next step is to check actual voltage reaching the PCM (should be about 0. 6V at idle, DRB live data is showing 5V at the PCM, IOW, full throttle all the time)



Any DC techs out there that can tell me if I'm on the right track?

 

[Got HO?]

Thanks to TWest who sent me a "test unit" PCM, my truck is now shifting properly. Its great that there are fellow TDR members who are willing to help dummies like me Oo.



Now, anyone have a good used PCM for a 2003 2500 A/T slt for sale?