The 4WD transfer case encoder motor position sensor or the selector switch may fail causing the service 4WD message to be displayed. Fault code(s) stored in the transfer case control module will be of assistance in determining the exact fault causing the message to be displayed.
Problems for specific GMC Sierra 1500 years:
Car problem reports
Problem with your car? See what our experts say or submit your own.
Newest reported 2012 GMC Sierra 1500 problems