GMC Complaints

The contact owns a 2010 GMC Terrain. The contact stated that while driving at an undisclosed speed, the service stabili-trak and check engine warning lights were illuminated. The vehicle was taken to O’Reilly Auto Parts, where it was diagnosed with a misfire in cylinder #3. The vehicle was then towed to an independent mechanic and the contact was informed that there was no compression in cylinder #3. The vehicle was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The vehicle was towed to the dealer, where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. In addition, the contact stated that several oil consumption tests were performed by the dealer over the past three years. The contact stated that after each oil consumption test was performed, the oil pressure was always a quart or more lower when checked; however, the contact was informed that it was not an issue. The manufacturer was not made aware of the failure. The failure mileage was approximately 120,000.

My truck went into "limp" mode and had very little power. It was towed to the dealership where they diagnosed the issue as a bad solenoid causing the engine misfires. The solenoid was replaced, but the issue was not fixed. Now the dealership is stating the engine has bent lifters and the repairs will not be covered under the ongoing massive engine recall. The vehicle had the pico test on 9/17 and it "passed", but less than 3k miles later and the engine failed. This is a clear safety issue and well known by NHTSA and GM. Now I'm negotiating with the dealership to cover repairs and my truck has been gone nearly a month.

Odometer Fraud. The contact purchased a 2022 GMC Sierra 2500. It was discovered that there was a mileage discrepancy. The vehicle was a dealer sale. At the time of purchase, the vehicle mileage was 92,000, and at the time of registration, it was discovered that the mileage was 98,325. The Carfax report was not available at the time of purchase. The mileage discrepancy was later identified through the vehicle manufacturer’s Mobile App.

I have 125,000 miles on my truck. I was traveling with my grandkids in the back seat. We were going through a four way stop. My truck started tapping like a lifter issue. The next thing I know is the truck engine light started flashing and car started to shake. Then, my truck lost all power and a big cloud of blue smoke came out of the tail pipe. The truck could not be driven any further. The symptoms: engine tapping, low oil, engine light flashing, shaking, lost all movement, and a cloud of smoke We had to tow my truck to the dealer and they are still accessing the issue. All symptoms are identical to the current recall of the GMC engines.

The morning of December 12th, 2025 I used my vehicle to transport my daughter approximately 5 miles round trip from our home to drop her off at daycare and then I returned home. I used my front and rear defrost elements to expedite removal of heavy condensation which had formed on all windows overnight. This was approximately 7 AM. I parked my truck in the driveway and went inside until approximately 11:45 AM when I went to leave in my truck and noticed the rear sliding window had shattered. The window shattered and distributed tempered glass fragments all over the inside of the cab. Only approximately 10% of the window remained intact. I then reviewed the security camera footage from my driveway and discovered that the window failed entirely on its own with nothing hitting/striking/touching the window, nor any humans or animals in the vicinity. I attempted to take the vehicle to a GMC service department this morning (Dec 13) but due to their demand to keep the vehicle for 2-3 days to investigate yet unable to provide a loaner vehicle, I was unable to leave the vehicle in their possession and returned home. I plan to continue to contact GMC dealership service departments in hope I can find one which can provide a loaner vehicle, as I will need transportation to and from work in the coming days. I do have video footage of the incident although I am unable to add it below.

When driving vehicle, alert sounded lowered speed detection and my engine light came on. My vehicle then lagged power and it smelled like something was burning. Called dealer i bought vehicle from and i drove it in to them. I just bought the vehicle 8 months ago. I was just in to same dealer for a GPS tracker that was in my vehicle unknown to me that the Onstar stopped working and the dealer had stating they missed it in the pre certified inspection and they had to replace the telemax module do to the unknown GPS Tracker. My vehicle is now in for the lowered speed detection problem which my GM app stated it was an air induction system problem. I do not have paper work for the air induction system yet but i have sent photo of what my GM app produced.

Bad vibration and bad wobble in steering wheel and front end components. This is the 3rd or 4th time my truck has been back to the dealer because of the same issue!

Sitting at stop light engine began running rough and smoke coming out. CEL came on and began flashing, pulled over and had it towed. Diagnosis was PO300 misfire, dead miss on cylcinder 4, cylinder plug 4 is fuel fouled, cois is fine has good spark- caused by failed lifters. Needs engine replacement. Vehicle always serviced, garage kept and in mint condition with 89K miles.

The contact owns a 2019 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the transmission unexpectedly hard downshifted. No warning lights were illuminated. The contact stated that the vehicle was hesitating while driving the rest of the drive. The vehicle was taken to the dealer; however, no cause for the failure was found. The dealer performed an 8-speed transmission fluid and filter replacement. The contact stated that the failure persisted. A month later, the contact stated that on a separate occasion, the transmission unexpectedly downshifted. No warning lights were illuminated. The vehicle was taken to the dealer; however, no cause for the failure was found. The contact stated that the failure persisted. The contact stated that a month later while her husband was driving on the freeway at an undisclosed speed, the engine seized and the rear-end locked and threw the driver into the steering wheel even though the seat belt was securely buckled. The contact stated that the transmission was stuck in drive(D), and the vehicle was unable to move forward. The driver shifted into reverse(R) and was able to pull off the freeway. The contact stated that the vehicle was then driven to an empty parking lot and left overnight. The vehicle was then picked up the following day and was driven to the dealer; however, no cause for the failure was found. The contact stated that the failure persisted. The manufacturer was notified of the failure. The contact hired a GMC engineer to inspect the vehicle and informed the engineer that the vehicle needed to be driven a minimum of three days and 300 miles before experiencing the failure. The contact stated that the engineer drove the vehicle for 100 miles. The contact stated that the GMC engineer and one of the employees at the dealer suggested replacing the PCM module because there was no fault code present during the failure. However, the contact was informed that there was no guarantee that replacing the PCM would fix the vehicle. The failure milea

Was driving my terrain and suddenly it started to shake and then check engine Light came on. Upon getting out I checked the dipstick and no oil was on dipstick. Start to put oil in and it's running out of the oil pan underneath the vehicle. Towed it home removed oil pan and engine parts laying shattered in bottom. Never got a low oil alert . Had codes misfire and knock sensor.