There are 1 owner-reported powertrain & transmission complaints for the 2012 GMC Sierrain NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
WHILE DRIVING AT NORMAL HIGHWAY SPEED, TRUCK SHUT OFF EXCEPT FOR THE LIGHTS. LOST POWERS STEERING, BRAKES ETC. ONCE I GOT THE TRUCK PULLED OVER AND STOPPED, ATTEMPTED TO RESTART. WAS UNABLE TO DO SO UNTIL THE 4TH ATTEMPT DURING A 5 MINUTES TIME SPAN. ONCE STARTED, APPEARED TO BE RUNNING FINE EXCEPT FOR THE MIL ON THE DASHBOARD WHICH WAS LIT.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 26, 2026