Hello All, and thank you in advance for your help or advice... Here go's: I have a 08 H2 (6speeed automatic) and the truck has been freaking out. 25k miles it started and now @ 31k and this has happened 4 times in between this mileage: the truck would be running fine, then while driving down the road, all service light would illuminate, then state service traction soon, the get stuck in second gear, as the only forward gear. Reverse, park work, would not shift manually with steering wheel mounted controls or from floor shifter, leaveing only: Park, reverse, or 2nd gear. Then would let it sit over night, the check engine light would be the only light illuminated when restarted next day, and would shift fine through all gears..........?????

The dealer: I've had it to the dealer ALL 4 TIMES... ugh... They've claimed to fix it each time, but I am slowly loosing my faith. first the fule sending selinoid, and cleaned valve body in trans, cleared codes. then the wiring to trans and cleared codes, then another selenoid of some sort, cleared codes, last but not least, ignition switch and accoding to dealer, was told to re-grease all electrical connections, clear codes and send me home...

Now I am afraid to rely on my H2, (why we all have them right) and take my family on cross country trips. ANY ADVICE OR KNOWLEDGE WOULD BE HELPFUL thanks in advace and reading this long questions..

 

What codes are coming up?

 

Thanks for the reply! and good question: lots of the paper work is construed as you may know: I am going back tomorrow to see if they can provide me with a complete list of codes ever thrown from the 4 visits. here are a couple: U0073, U0109, Code 0306... all in august: replaced Fuel pump flow control module, rechecked wiring, reprogrammed electronic brake control module SPS???? All forgien to me, just so agrivatted. I've googled eveything..... I think, hoping someone here has had the issue or can help me uncover somehting... thanks

 

I would start looking at the ECM. Based off your driving experience and the communications errors that's where I would focus some energy. It could be something as simple as brownouts in the electrical system so maybe start with the battery and work your way to troubleshooting the ECM. I'm not real strong here yet but I'm pretty sure everything you listed is controlled by that one module.

 

Hi get the dealer to check the wiring harness plug at the transmission to make sure all the pins are seated correct and have the correct pin tension . Also on the right side of the transmission their is a shield for the wiring harness that maybe cutting to the wiring harness. If their is a problem like you said the transmission will default to 2 or 3 gear and will not shift but will still have reverse and park. It sounds like its losing high speed GMLAN communications connection some where. Hope this helps.