Two problems related to power train have been reported for the 2012 GMC Sierra 2500. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2012 GMC Sierra 2500 based on all problems reported for the 2012 Sierra 2500.
Transmission control module failed.
Driving on the expressway around 60 mph when the truck went into limp mode slowing me down to 40 and then would not shift gears tcm went out gm told me that there is a big problem.