I have a 05 cobalt, base 2.2L. It has a shift shock when going from park, to rev, to drive. It only goes into 2nd gear and no other forwards, reverse does work. I got about 10 codes and can't find the paper where I wrote them down at, most were electronic power steering and trans codes. I can remember one was a U something about "no communication with TCM". I could not get this one to clear. I got a Tech2 and could not bring up the TCM for live data and no other modules could talk to it either. I checked all power supplies and all grounds for the TCM, all good, no shorts or opens that I could find. I had my gf bring her cobalt over and swapped tcm's. I could now comm with the tcm and all seemed well. I ordered a tcm, just put it in and have the same problem. Wtf? It worked fine with her tcm.... I didn't get a chance to ask the GM guys if it needed to be programmed but when they were swapped, I could real live data and clear codes.

I'm bringing the tech 2 home again tomorrow and see where I can get. Any help?
thanks

 

#01-07-30-002E MIL On, Transmission Stuck in Second or Third Gear, IPC Inoperative, DTCs P0740,P0753,P0758,P0785,P0787,P0973,P0976,P1860,P2 761,P2764 and/or P2769 Set (Verify and Repair Source of Voltage Loss - (Sep 23, 2005)

 

Kool, thanks!