Hi and welcome to Just Answer!
Is the vehicle still under factory warranty?
When was the last time the vehicle was at a GM dealer?
I assume so, I bought it new. I just want to understand the problem better, so I can interface with the dealer's repair manager better.
Take a look at this link--same problem as mine.
Thanks.
http://www.automk.com/thread-80531-1-1.html.
ASE Certified Technician
ASE Master Automobile Technician since 2000 17 Years + Exp.