Aaron Stuesser

Driving from WA to CA on a 700 mile road trip and about halfway my 2012 Jeep Wrangler JKU with 105k miles starts hard shifting on the freeway. I pull off and check codes and I have P2638 “torque management feedback signal A range/perf” as well as another one (that I didn’t write down the code for) for high voltage on the battery. I make it to a Napa auto part store and have them test the battery which is at 12.8 volts, not terribly high but it is hot to the touch and some of the caps have popped off. I also have a loose battery terminal where the bolt that tightens the terminal is broken so I swap a new battery and put a hose clamp on the loose terminal. Clear the codes and it runs fine until the end of my trip, with the exception of one moment of hard shifting up a steep grade in high heat but after a short dinner break I check and no codes have fired and I make it the rest of my trip without event.

Two days later driving on surface surface streets after ten minutes and it starts hard shifting again and the P2638 code has fired again. The local Dealership is booked for a week and I need to get home so I go to Aamco and they run codes and test drive it and say that it is only firing P2638 which is odd because that code usually fires with other codes. They are looking into it further but are currently stumped as to what could fix it. Thoughts?

i have a 3 inch lift and 35” trail tires and recently had an issue with the TCS light coming on after some trail driving when the steering wheel got crooked but I reset the wheel and cleared the codes and have not had issues since. Also the CEL does not light up when it is hard shifting but the code still fires.

LC Boyer

My best educated guess is you have a loose connection, probably at one of your battery connections or ground. The PCIM could be be loose

Njirishrob

Did you ever get this sorted out? I have a 2012 JKU (96K miles) with the same problem