Just got back from a test drive after removing the drivers side end cover on the automatic transmission in my 2009 HHR w/2.2l engine.Car has been commuter, currently has about 240k miles, runs like a top. I will start by saying thanks to all who contributed to other threads about shift solenoid replacement. Fastsuv, Donbrew, Old Blue etc, All of your input and experience was helpful in completing my project. That being said, I still have an issue I need your advise on.
Original issue was: while backing out of a parking spot at the market, when I shifted to Drive I thought someone had rearended my car, it banged into gear so hard. Drove it home, all gears work every shift Very hard. Pulled code P0742, TCC solenoid stuck on. Unplugged the connector at the TCM and Ohmed out the TCC Solenoid, got about 3 ohms, After reading all the thread on the subject here, decided it was worth it to see if changing the Solenoid would fix it. Replaced all the solenoids while I was at it, as Oldblue had recommended to Steve(Fastsuv) . Got it finished this morning, Test drive was great, issue fixed. Shut it off in the driveway, started cleaning up the garage, went back out to move the car and Bang, issue is back! No code yet with my scanner.
I went from happy to 'oh hell' in a heartbeat. Any thought? I am not sure where to go from here... Thanks Steve T. (Hotwireflyer)

 

Are there any codes?

Even if the CEL isn't on, there may be a pending code.

Steve

 

Recheck your work, no codes, try a full 30 minute battery lobotomy.

 

Over nite battery disconnect, no change. Just took for an 8+ mile test drive,fwy and streets, Stalled once coming to a stop, drives like it did originally, i:e: very hard shifts every gear , returned to the house and put the reader on no codes. Tried swapping another TCM in from the wife's 2011 HHR same drive line, no change.
Your thoughts would be appreciated... Thanks

 

Old Blue, I took end cover off trans, replaced all solenoids while in there, and new gasket, 7 qts DexVI Test drove perfect, parked it, came back an hour later, Bangs into gear, shifts hard every gear, no codes. Checked connector at TCM and trans case, no obvious issues. Swapped in known good TCM, no change.

 

What resistance do you read now for the TCC Solenoid at the TCM?

Steve

 

Wire diagram

https://www.powertraincontrolsolutio...0GM%204T45.pdf

 

I have not looked at it for a week, needed a break. Fastsuv, I don't recall what pins I probed to check the TCC solenoid originally, hope I did it correctly. Old Blue, I do not recognize the the TCM connector on the schematic you linked to. Took for a longer drive yesterday, Still shifts very hard does a double bump on most shifts, Rechecked for codes and now have 2, P0742 and P0842.
I am at a loss to understand why it worked perfectly after replacing all the solenoids on my original test drive, and how it went awry immediately after that. It may be time to see an expert...

 

Potential causes,

https://www.obd-codes.com/p0742

https://www.obd-codes.com/p0842

a short or pinched wires was the cover tight over the harness?
have a read of these codes, perhaps it an easier fix then you thought

 

So I had shift solenoid codes and got into tye transmission and changed them. Put it all back together and went to start and blew #43 fuse and burnt out starter. Took tranny back apart and the tcc solenoid I didn't replace, connector had melted off. Ugh. Now have to hope when I put in New solenoid and connector it's fixed. Anyways when you replace the tcc the tcm needs reprogrammed which is why you're slipping and banging gears. There a couple ways to reset the tcm but afterward you have to drive it 20-50 miles for the tcm to adjust to the new tcc. It should smooth back out afterwards