Is this procedure good for my truck, 03 Dodge Cummins? I am getting P0123 in the PCM and is in limp mode. For awhile after warmed up would drive ok. Was shifting in all gears, then it stayed in limp mode and local mechanic grounded the trans relay in the fuse box, then it shifts but no OD Now stays in limp mode when not grounded in fuse box. Replaced APPS with TIMBO's APPS at http://www.dodgecumminsapps.com/index.html, Made no difference.

Trans relay good? Try swapping with another relay... I would skip the ground though... Also clear any codes present... As for the APPS error code try clearing the code and see if it returns... Also did you do the APPS relearn too?

I swapped relays, all good. Yes I did the learn procedure and continues to be in limp mode. I have a mechanic who I want to follow your procedure for diagnosis but is it for my 03?

Should be basically the same... Just a matter of checking the wiring from pin to pin for shorts and opens...

I don't believe it, only trouble code is the APPS high voltage

Should be basically the same... Just a matter of checking the wiring from pin to pin for shorts and opens...

Could try this... http://forum.mopar1973man.com/threads/2557-P0123-Accelerator-Position-Sensor-(APPS)-Signal-Voltage-Too-High

Dealer located bad connection at middle PCM connector. Running like a champ.

Hopefully you didn't find that out "just recently"!!!!I hope you just didn't have time to post the cause of the problem!!!

I burnt ground wire to pcm, replaced by shade tree mechanic who also broke the pcm by exploring inside. $400 replacement. After extended time with no results from shade tree guy I let sit. Then a place called Promotive in Visalia said take to dealer because it must be software problem. $85. Then dealer in one day replaced middle connector $300. So I am in the red trying to avoid dealer.. Should have started with dealer.