Found this thread on another Dodge Site,

I know when I was searching for the solution to my Durango's problems I noticed a lot of people were just as baffled as I was but I finally found the solution.

First I replaced the sensor and solenoid. Nothing worked. Then I bought a refurbished ECU off ebay since some people on here said that it fixed their issues but it didn't do anything for me and i returned it. Then I took it to a tranny shop and the guys checked every sensor and thing that could be plugged in. Still, the truck was stuck in limp mode and throwing the same codes.

Took it to another tranny shop and they noticed all the wiring above the tranny was melted and tangled together. One of the connections was totally F-ed. Seems like after all the miles (over 100K) and high temps melted the plastic around the wires and made some of them cross n' tangle.

So then I had the guys at the shop re-wire the tranny. Still didnt work. Figured we'd try out the PCM issue with the new wiring and put in a PCM from a 5.9 dodge van at the shop and it finally worked! It was out of limp mode and shifted beautifully in every gear.

Got on Ebay bought another refurbished PCM (from Auto Computer Exchange off Ebay) and now it runs like a dream and everything works properly. Although, I think I may have damaged the tranny a little bit from driving it in limp mode for a while.

Anyway. For anyone that is having transmission issues that were like mine I recommend checking the PCM first. Any PCM from a similar year and engine as yours will work. So dont go buying a new one just yet, find a buddy or someone that will let you plug theirs in first. If the PCM is from a different model or vehicle your gauges wont work but your tranny and engine will. Although, just cause the PCM didnt change anything doesn't mean its bad, still could be other things. So if the PCM doesn't change anything check the wiring to the tranny. Maybe you have a connection problem or the same melted wire problems I had. If so then it could be the root of your problem. If your wires are good then i'd look into replacing the solenoid and sensors inside the tranny (easy to do yourself but messy. Just drop the tranny oil pan, and plung n play). If the sensors are good or newly replaced, and the wiring to the tranny is good, and its still not working, then its highly likely that your PCM is bad too and has to be replaced (which happend to me).

 

New PCM installed, still have codes P0622,P0037,P0138 and P1763
Still have shifting issues periodically,(Limp Mode) and gas mileage could be alot better.... back to another mechanic tomorrow, I'm stuck, I've changed all sensors and PCM, has to be in the harness. I've noticed but not sure it makes a difference or not but theres been a voltage regulator added to the altenator before I purchased this truck, as a band aid maybe?, plus I have noticed a cut green wire on altenator not in use? Truck charges fine as far as I can tell??

I'm ready to light a match

 

Original voltage regulator was in the PCM.

P0037 HO2S Heater Ctrl Circ Low Bank1 Sens2
P0138 1/2 O2S Shorted To Voltage
P0622 Alternator Field Not Switching Properly<- probably due to having an external regulator.
P1763 Governor Press Sens Volts Too Hi

Wonder if you have a harness pinched somewhere........

 

what was the final outcome with your little project. im at the same point you were with coming down to the line with replacing the pcm. hope you can provide some input. thanks

 

Thanks for the info here. I'm fighting a P1763 and p1762 myself. I dropped pan and changed sensors, waiting for a part in the mail before I finish up. Did not know downstream O2 could be a culprit. Hope you find the problem.

 

I did not find the source of the issue with the harness. It physically cannot be anything else because I've changed everything. But, what I have accomplished is a work around for now and I've been having success since, I simply unplugged the rear O2 sensor completely, I have codes for such but no longer have tranny issues at all, shifts perfect, apparently both the 02 sensor and the solenoid and transducer in the tranny share the same data feed wire back to PCM, therefore causing false reads. Design flaw for sure. It worked for me, hopefully for you as well, short of changing harness. And my truck runs fine with rear 02 unplugged.