40 mph RPM bounce
06-22-2016, 03:50 PM
#12
Member
Join Date: 05-27-2015
Location: N. America
Posts: 95
Me too....... !
Got a 08 HHR, LT with 2.2 eng., automatic transmission, 107,000 miles... and it's doing the same thing. . . BUT it is doing it a little too at 60 MPH, PLEASE check yours on this point and let us know.
I would say to first… check the TCC solenoid valve resistance at 10-11 ohms at startup (eng. cold) and 16 ohms when HOT, as stated by the GM info. Thanks to: donbrew, DrLoch and OldBlue for the research.
Second… check the fluid levels. Third… keep looking and searching.
Good to know I’m not the only one with the problem, YES I know this is not the answer to the problem but tells me it is a problem. I say it/something is broken or all would have it from day one and not just some having it now. As in all problem’s it would be nice to have a code/ light to put us in a direction to fix it. If we find that we have to live with it and it will run that way… so be it. Just would like to know……..?
I would say to first… check the TCC solenoid valve resistance at 10-11 ohms at startup (eng. cold) and 16 ohms when HOT, as stated by the GM info. Thanks to: donbrew, DrLoch and OldBlue for the research.
Second… check the fluid levels. Third… keep looking and searching.
Good to know I’m not the only one with the problem, YES I know this is not the answer to the problem but tells me it is a problem. I say it/something is broken or all would have it from day one and not just some having it now. As in all problem’s it would be nice to have a code/ light to put us in a direction to fix it. If we find that we have to live with it and it will run that way… so be it. Just would like to know……..?
07-21-2016, 06:51 PM
#14
Member
Join Date: 05-27-2015
Location: N. America
Posts: 95
Any up dates you found?
Has anyone found any thing on this? There has to be an answer... I add the following 2 cents:
On the 40 mph RPM bounce do you know anyone that had a scope put on it to check the throttle body set up back to the accelerator petal to see if all that drive by wire is working correctly? I don't know who or were to ask for that but feel the problem could be in this electric run/ section due to it being in the same area of trouble (around 40 mph). But it could be in the fuel system or firing or ECM or TCM as well. Think also that doing a monitored driving test with a scanner hooked up may be the only way to find it. Again... how long has your's been doing it? Mine for 4 months that I noticed it, could be 6-9 months or more!
Regards, JC
On the 40 mph RPM bounce do you know anyone that had a scope put on it to check the throttle body set up back to the accelerator petal to see if all that drive by wire is working correctly? I don't know who or were to ask for that but feel the problem could be in this electric run/ section due to it being in the same area of trouble (around 40 mph). But it could be in the fuel system or firing or ECM or TCM as well. Think also that doing a monitored driving test with a scanner hooked up may be the only way to find it. Again... how long has your's been doing it? Mine for 4 months that I noticed it, could be 6-9 months or more!
Regards, JC
07-21-2016, 08:27 PM
#15
Administrator
Join Date: 10-13-2011
Location: Welland,Ont Canada
Posts: 36,435
Mine has been doing this awhile, I have discussed last week with my local dealer service manager he is setting up an appointment to review any history in the computers systems . I'll let you know!
07-22-2016, 08:08 AM
#16
Technical Moderator
Join Date: 01-23-2009
Location: Fredericksburg, Virginia
Posts: 24,660
I think somebody narrowed it down to a firmware module in the TCM. I doubt any normal GM tech would have a clue, you would need someone who only works on this transmissions. In other words; it is not a generic problem, and as much as they would like you to believe otherwise GM technicians have generic educations.
Any decent mechanic that can haul a tool box can get a job at any agency, GM, Ford, Chrysler, Ferrari etc. I know a guy that worked at 3 different shops in 4 weeks (not because he got fired, got better offers).
Any decent mechanic that can haul a tool box can get a job at any agency, GM, Ford, Chrysler, Ferrari etc. I know a guy that worked at 3 different shops in 4 weeks (not because he got fired, got better offers).
07-22-2016, 08:41 AM
#17
Administrator
Join Date: 10-13-2011
Location: Welland,Ont Canada
Posts: 36,435
My transmission shop sent me tithe dealership because he a: doesn't have a scan tool that can reflash the TCM, and b: he took the HHR for a test drive was able to duplicate the problem, went and took the GM dealership service manager for a test drive and they both concur it's an issue with the TCM or electrical, so they are both working together on this , they mentioned could be torque converter and shift solenoids, we'll see next week!
