Pin 29 is the signal return wire. with the trans unplugged, there should NOT be power there.

Think I might be tempted to peel that particular part of the harness open, and physically inspect the wiring from the PCM to the trans. Gotta be a short in there somewhere.

 

I am going to try to search again for short but it's strange that the actual pin on the pcm at 29 has the voltage and that is without c2 connector plugged in at all. I don't even know where to start looking for short because I have no continuity from pin 2 to pin 4 on trans connector and I would think that's where the 5v could be shorted to signal wire if there was a short. Could you tell me what else shares a ground with trans connector ground? I have tried unplugging O2 sensors even though they where reading probably. They never went over .9v

 

Due to the way the wiring diagrams are laid out, no..... not easily. Pin 28 should NOT be showing power with the connector out of the PCM either. That is NOT what I would consider a 'common' failure, and getting a second PCM with the same problem is unlikely in the extreme. Did you get an actual replacement? Or did you send yours in for repair??

 

Actual replacement brand new they had to program vin mileage and tire size. I have both pcm here now

 

Pin 28 has no power, pin 29 has power

 

Wish I knew someone with another 2nd gen ram that I could read there trans connector voltage on that signal wire

 

RIght, pin 29.... typo.

I can't find any troubleshooting for that one.... Probably in a book I don't have. (though one would think, it would have been part of the FSM download??)

 

I unplugged throttle position sensor I tested voltage on tps with key on and got 5.18 on 5v feed and signal return wire. If this is correct maybe I should have 5v on trans signal wire or this sensor wiring is also tied into this problem

 

Pretty sure a fair few sensors share the five volt feed, their signal return wires though should be separate. You really shouldn't be seeing 5 volts on the signal return wire..... that should set a code for TPS out of range, or some such. Plug it in and test voltage on the signal return wire. Should be less than 1 volt with throttle close, and greater than 3.5 at WOT.

 

Tps is working normal. Did some digging and I am getting 90 ohms on the ground circuit C1 connector unplugged slot 4 to trans connector slot 3 it is a black wire with light blue stripe. I unplugged both O2 sensors (they also have same wire they are also reading 90 ohms. The only other place I see black/light blue is tps and that rings out perfectly to ground. Any test that u would recommend I would like to run a new wire from pin 4(also I don't know what color it changed 2 at pcm) to trans.