GMC Terrain Complaints

3,167 consumer complaints on file.

#11755131August 5, 2026
ENGINE, POWER TRAIN, FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL
adaptive cruise disengaging alert on dash- no cars or weather conditions to induce this. loss of power and bucking on highway( near accident caused) catostostrophic sudden loss of power engine/transmission failure while mechanic driving resulting in car towed back to dealer. loss of power multiple times causing near accidents. sudden jolting at stop light causing car to propel forward requiered both feet on brake pedal to stop. 4 episodes of near collision 1st altert started 04/4/2024 adaptive cruise light on dash 14,700 miles on vehicle 5 episodes continued and now car is still at dealership for emissions failure, loss of power x 4 weeks. ALL PHOTOS OF DASH LIGHTS, REPAIR INVOICES AND VIDEO OF DASH AVAILABLE BUT I AM NOT ABLE TO UPLOAD ALL.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11754945August 5, 2026
FUEL SYSTEM, GASOLINE
The contact owns a 2022 GMC Terrain. The contact stated that while driving 40 MPH, the vehicle lost automotive power. No warning light was illuminated. The vehicle was pulled over to the side of the road. The “Low Fuel” message was displayed on the instrument panel. The contact stated that the vehicle failed to restart. The vehicle was towed to a local dealer where it was diagnosed and determined that the fuel pump was inoperable and needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 51,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11754923August 5, 2026
POWER TRAIN, ENGINE, FUEL SYSTEM, GASOLINE
The contact owns a 2023 GMC Terrain. The contact stated that while driving at various speeds, the vehicle unexpectedly decelerated and failed to properly accelerate. The service transmission and service fuel management system messages were displayed, and the check engine warning light was flashing with several other unknown warnings illuminated. The vehicle was taken to the local dealer and while test-driving the vehicle, the vehicle stalled. The vehicle was towed back to the dealer. The cause of the failure was not yet determined. The manufacturer was notified of the failure, and an engineer was sent to the dealer to inspect the vehicle. No further information was available. The contact stated that the transmission module was previously replaced, but the failure persisted. The failure mileage was 27,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11754857August 4, 2026
ENGINE
At 12,000 miles removed old air filter found grass under air filter
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11754433August 3, 2026
SERVICE BRAKES, HYDRAULIC
The contact owns a 2018 GMC Terrain. The contact stated that while driving at an undisclosed speed, the brake pedal was depressed; however, the vehicle failed to stop as intended. The contact stated that the brake pedal was abnormally firm. The brake pedal was depressed to the floor, and the vehicle came to a stop. The check engine warning light was illuminated. The vehicle was towed to the dealer. The vehicle was not diagnosed. The contact referenced an unknown recall; however, the VIN was not associated with a recall related to the failure. The manufacturer was not made aware of the failure. The failure mileage was approximately 95,300.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11753729July 30, 2026
SERVICE BRAKES
While driving north in interstate 79, the brakes became very hard to push making it difficult to stop the vehicle. We got off the interstate and proceeded back home. The brakes were as hard as a rock to push and it was difficult to stop the vehicle. When this happened, the check engine light came on and stayed on. It was very dangerous to drive due to the brakes not working properly and the stopping distance was greatly reduced and it was difficult to stop the vehicle putting our family at risk for their safety. We took the vehicle to a repair shop and they checked and diagnosed the issue and told us the vacuum pump for the brakes was no good and needed replaced. We found that this is a common issue for breakdown on our type of vehicle. Repairs were made and the total cost was $352.24 including tax.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11752293July 23, 2026
SERVICE BRAKES, ENGINE
Vacuum pump failure causing sudden and unexpected hard brake pedal and loss of braking coming off the highway. Ended up catastrophic engine failure. This is the SECOND incident with this vehicle of the exact same problem. GMC refuses to address this issue and continues to risk the lives of their customers.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11752313July 23, 2026
STRUCTURE:BODY
My cousin thought I had a trailing arm bushing was bad on the driver's side. The subframe holding the trailing arm rusted out completely. He was able to put his thumb through it with little pressure when trying to see if it can be fixed.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11752310July 23, 2026
UNKNOWN OR OTHER
The rear access closes on its own after sitting open for a period of time. I was sitting at grocery pick up with the access open. This caused it to close on worker at grocery pick up. It stayed closed and I had to hit the button to open it back it did not auto go back up when it couldn’t close.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11751978July 22, 2026
ENGINE
I am submitting this complaint regarding the engine timing chain failure in my 2015 GMC Terrain because I believe it presents a serious safety hazard. Before the failure, the vehicle began experiencing intermittent symptoms, including engine jerking, shaking, rough operation, abnormal engine noises, and an intermittent check engine light. While driving on the highway, the engine timing chain failed, causing the vehicle to suddenly lose power. I was traveling at highway speed and had to safely maneuver the vehicle out of traffic. The unexpected loss of power placed me and other motorists at risk of a collision because I could no longer safely maintain the flow of traffic. The vehicle was towed to an independent repair facility, where the engine was diagnosed with a timing chain failure. I was informed that the engine had sustained significant damage and required replacement. After purchasing and installing a replacement engine, that engine also began exhibiting timing chain-related symptoms immediately after installation, including abnormal rattling noises and unstable engine operation, resulting in additional repairs and the vehicle remaining unsafe to drive. I am concerned that timing chain failures in this model can occur without sufficient warning and can cause a sudden loss of engine power while the vehicle is being driven. A sudden engine failure at highway speeds creates a significant risk of a crash, injury, or death. I am requesting that this issue be investigated to determine whether it represents a safety-related defect affecting other 2015 GMC Terrain vehicles.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11752244July 22, 2026
SERVICE BRAKES
Vehicle would slowly roll even when break is applied. It was confirmed by the service center that the break booster vacuum pump was only reading 8 when it should be at 27. It was not making enough pressure. The vehicle would not stop when break was applied.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11751551July 20, 2026
SERVICE BRAKES, HYDRAULIC
The contact owns a 2015 GMC Terrain. The contact stated that while driving 5 MPH, the brake, ABS, and stabili-trak warning lights were illuminated. The dealer was contacted and diagnosed the vehicle with an Electronic Brake Control Module failure. The dealer stated that the manufacturer no longer manufactured parts to repair the vehicle. The manufacturer was not made aware of the issue. The failure mileage was approximately 167,446.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11751242July 18, 2026
SERVICE BRAKES
I was traveling down the interstate at 70mph. Traffic began slowing ahead of me. I hit the brakes and the pedal was rock hard and I could not stop my vehicle safely. Service brake assist light flashed momentarily. Ended up being the vacuum pump. I was told by the dealership I had it towed to that the vacuum pump had broken off and failed. This was an absolutely horrifying situation that could have caused severe injury or death.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11751287July 18, 2026
UNKNOWN OR OTHER, ELECTRICAL SYSTEM, SEATS
The back passenger seat exploded and caught fire, burning the back of the seat in front and burning the ceilings. Inside the whole vehicle is black from smoke damage. Incident assessed by fire marshal who has ruled as electrical issue. No warning lights or systems displayed anything.
Crash:
No
Fire:
Yes
Injuries:
0
Deaths:
0
#11751119July 17, 2026
SERVICE BRAKES, ENGINE, FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING
The vehicle has had regular maintenance, oil change, and inspection including the brakes. My boyfriend is visiting me in [XXX] from the [XXX]. OnXXX while driving the vehicle the engine started. Making a ticking noise especially during idle and when accelerating in idle. About 15 minutes after the ticking stopped and all of a sudden there's a complete loss of breaks they locked up and the driver was unable to efficiently stop while going down a hill Road. Driver had to use the emergency brake to make the other brakes release and then the brakes from there would not work even though you could stomp on them stand on top of them there was no breaking power anymore. Vehicle was brought into a GMC dealership on the following Monday where they confirmed the issue was a failed vacuum pump connected to the engine and camshaft which is a known safety issue to GMC as part of an ongoing open case they had specialty coverage and bulletins regarding the Tahoe and Sierra but neglected to include the terrain on this issue. Cold the GMC manufacturer in both [XXX] and [XXX] to try and get cost assistance and specialty coverage as the vehicle as well under the mileage requirements but have been giving the push around and zero assistance. The risk to the drivers and passengers lives was significant as we were on the highway for1.5 hrand thankfully the brake lost didn't happen in full during that time. The repairs were completed and paid for in full by the client which should have been covered by the dealership and we are looking for cost recuperation and are now being ignored. Receipts are here to substantiate the claim. The ABS light is no longer on there was no warnings on the vehicle showing any issues or any codes as OnStar was called and diagnostics were received and the diagnostics came back clear prior to this happening, and following the break failure. Lack of codes and warnings is life-threatening and serious. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11750466July 14, 2026
FORWARD COLLISION AVOIDANCE: WARNINGS, FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL
I was driving about 55 mph with adaptive cruise control set to maintain a three-car-length following distance. It was raining, and when the vehicle in front of me slowed down, my vehicle did not detect it or slow down as expected. Instead, it continued accelerating, and I had to brake to avoid rear-ending the vehicle ahead.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11749897July 13, 2026
POWER TRAIN
Leaking transmission fluid at 7,000 miles. Technicians noticed during routine oil change at dealership.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11749838July 12, 2026
SERVICE BRAKES
Vacuum pump failure caused my brakes to lock up and almost caused me to wreck into another vehicle
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11749649July 10, 2026
FUEL/PROPULSION SYSTEM
Vehicle was filled with a full tank of gas, went to crank the car up to go home from work it acted like it wanted to crank but seemed to be getting no gas. Diagnostic was performed and the fuel pump control module failed. I thank God It did not start because if it did and I just so happen to pull out into traffic and the car just die in the middle of the road I don't think it would of been pretty. Frankly I think it would of be a very dangerous situation. My vehicle was not part of the recall but somehow my vehicle was still affected hopefully GM would look into the 2020 Terrains with the 2.0 engine. Maybe I will be reimbursed.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11749358July 9, 2026
ENGINE AND ENGINE COOLING
See attached document for complaint.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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