GMC Complaints

Muti pro tailgate has electric issues due to moisture. Tailgate will open up driving down the road.

Complete engine failure with no warning on major road in heavy traffic. Very dangerous situation to pull off safely. Vehicle was towed to dealer and confirmed engine is seized. Unknown cause at this time. Transmission has had valve body replaced prior to engine failure. Transmission still has shudder after valve body replacement and prior to engine failure.

My engine started making a clicking noise like a playing card in a bicycle spokes. Was able to drive and make it to dealership and they determined that my engine crankshaft had to much end play and they needed to replace the engine. They had my truck approximately 2 weeks, did not provide me a loaner, nor any reimbursement for being without my truck during this time. My truck was still under the factory bumper to bumper warranty at the time.

Top of roof pops when you shut car door, Leaking either transmission fluid or oil, Left turn signal doesn't stay engaged when turning, Side mirror warning lights randomly go off when no car is around. Car is not shifting correctly when driving

Severe recurring roof water intrusion on 2022 GMC HUMMER EV; repeated failed repairs; interior rust/corrosion; safety concerns in high-voltage EV. Vehicle: 2022 GMC HUMMER EV Edition 1?VIN: [XXX] Current mileage: ~12,000 miles? ?My vehicle has a recurring defect involving severe water intrusion into the cabin through/around the removable roof panels/roof sealing areas during rain. Despite repeated dealership repair attempts, the vehicle continues to leak. The ongoing water intrusion has caused visible corrosion (rust) on interior metal structures, including the floor area and seat rails/seat mounting areas. The corrosion indicates prolonged moisture exposure inside the cabin. The dealership has attempted to repair this water intrusion issue approximately six (6) separate times, and the defect remains unresolved. First documented repair attempt: 03/14/2023 (issue presented to dealership for correction) Most recent repair attempt/out-of-service: 12/29/2025 to 01/06/2026?The vehicle has spent weeks at the dealership across these attempts, including time waiting for parts and work completion. Even after these repairs, the vehicle is still leaking and the corrosion is still present. ?Because this is a high-voltage electric vehicle, I am concerned that water ingress and corrosion are compromising electrical wiring/connectors and safety systems located in/near the cabin floor and seat areas (including areas where sensors and connectors may be present). I am concerned this could increase the risk of electrical short, malfunction of safety systems (including airbag sensors), and in a worst case scenario a fire risk if moisture reaches sensitive electrical components. I can provide photos/videos of active water intrusion and corrosion and all repair orders upon request. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

While driving down the interstate a notice popped up on my dash about the brake assist. When I attempted to slow down the vehicle to safely pull over the brake pedal was very hard to push. I was able to slow the vehicle to a complete stop but needing to use both feed and press hard with all my weight. Once the vehicle was parked and shut off I turned it back on to have the check engine light pop up on the dash. I contacted Onstar and was towed to a dealership. The brake vacuum pump had broken off at the cam shaft and required extensive repairs. It is my understanding that this is a common occurance and there were previous recalls on the other style Terrains due to the same issue. yet they used the same part on the newer body style being fully aware of the design flaw.

My right headlamp/ turn signal assembly began flashing at random intervals. The high beam would come on and off randomly. The entire assembly would randomly flash along with the turn signal. The headlamp would go on and off randomly. This included switching between setting. High beam, low beam, daytime running light, and completely off with no warning. This causes blinding conditions for oncoming drivers, loss of visibility for driver, and loss of visibility during inclement weather due to high beam coming on and off, then entire unit turning off. As of right now, the vehicle is undrivable due to incorrect lighting, and flashing lights.

There is a Service Bulletin on the Engine Oil Cooler line failure. It leaks or becomes detached form the crimp joint. Mine is leaking from the crimp joint and GMC says my VIN is not covered under this bulletin. N192220080 if this is a known issue on these vehicles why am I having to cover the costs for replacing a known faulty part. GMC said I could bring it in and have them perform the repair at my cost. The nearest service department is 100 miles away. I have it at a local mechanic that says it will cost anywhere from $1300 to $1500 to perform the repair.

The contact owns a 2021 GMC Sierra 1500. The contact stated that after driving on a trip, the contact noticed that the vehicle had lost 10 MPG after a software update was performed. The check engine warning light was illuminated. The vehicle was taken to Richardson Chevrolet (3825 S Huron Rd, Standish, MI 48658), who confirmed that the vehicle was working as designed. The check engine warning light was reset. The vehicle was not diagnosed or repaired. The manufacturer was contacted and opened a case, and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 57,000.

My 2020 GMC Sierra with a 5.3L engine and 78,272 miles on the vehicle, experienced damaged lifters which also resulted in a damaged cam shaft. The total repair bill was $9,208.86. While in the GMC dealership for repair, there were 2 other trucks - same model, same year, same engine - in for the same repair. When searching on-line, I found the recall for the GMC 6.2L engine for similar issues. It is my opinion that the 5.3L engine is experiencing the same types of issues. I have driven GMC trucks for almost 40 years and have never experienced these types of issues. I have been told by several people that it is related to the Dynamic Fuel Management system and to fix the problem to disable the system to keep the truck in V8 mode. There are several solutions on line to make this happen. I am no engineer and only provide this as background information. From my perspective, it is clear that GM has a problem (whatever the root cause) with their 5.3L engines.