2024 Gmc Terrain

Factory powertrain programming actively locks out 9th gear (overdrive) during freeway driving at speeds exceeding 60–65 mph. The vehicle refuses to upshift from 8th to 9th gear, forcing sustained high-RPM operation during standard highway cruising.

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.

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.

Leaking transmission fluid at 7,000 miles. Technicians noticed during routine oil change at dealership.

The vehicle has experienced a recurring transmission-related defect that has required multiple repair attempts by an authorized GMC dealership. The transmission system has also exhibited fluid leakage. Despite prior repairs, the problem has continued to reoccur. Transmission and associated transmission fluid sealing components. The vehicle is currently available for inspection upon request. A transmission is a critical safety component that transfers engine power to the wheels. A transmission defect or fluid leak can result in loss of propulsion, hesitation, inability to accelerate as expected, unexpected changes in vehicle operation, or transmission failure while driving. These conditions could increase the risk of a crash, particularly when merging into traffic, crossing intersections, or traveling at highway speeds. Transmission fluid leaking onto roadways or vehicle components may also create additional safety concerns. The vehicle has been presented to an authorized GMC dealership for diagnosis and repair on multiple occasions. The dealership has acknowledged and attempted repairs related to the transmission. The vehicle has been inspected and repaired by authorized GMC service personnel. No police involvement. No independent inspection has been performed at this time. Manufacturer-authorized dealerships have documented the repairs. Symptoms included transmission-related concerns and transmission fluid leakage. The defect first appeared while the vehicle was under warranty and has continued despite repair attempts. The recurring nature of the transmission defect and fluid leak has reduced confidence in the vehicle’s ability to operate safely and reliably. The vehicle remains under warranty and has undergone multiple repair attempts without a permanent resolution.

Accelerator lag from any speed or stop. The care will take several seconds to hunt for the correct gear before shifting to accelerate. Or it will delay acceleration for several seconds while your pressing the accelerator. No SES indicator active. Mechanics can’t find issues. Other owners on forum a report the same sluggish behavior. These 1.5 turbo cars seem to need a software fix that they are not receiving. It’s like the drive by wire doesn’t register. Affects any gm vehicle with the 1.5 turbo and 9 spd auto.

Since purchase, this vehicle has consistently had an issue with the fuel system. When I call GMC they state only use no ethanol fuel. I wouldn’t have bought this car if that was the case. The dealership never said that when I was buying it. We replaced the entire engine for $11,000 because of a torn radiator hose, overheating and cracked a gasket. Now, the car is refusing to drive, giving engine power reduced

This is a continuation for NHTSA campaign number 11711615. While an additional NHTSA complaint has been filed for the power train, this focuses specifically on design failures in the braking system. Our vehicle experienced a highway failure of the fuel pump, but due to the nature of a powertrain failure the car could not be put into neutral, only remain in park. The car was stranded in the middle of the road. As a AWD vehicle it similarly could not be towed as both wheels were fully locked. Tow informed us that there should be a manual release under the shifting column, however, this design safety feature had been removed in the 2024 iteration. The car was stuck on the road behind a blind turn on a somewhat busy road with vehicles typically traveling between 25-50 mph. The failure of a manual override for neutral and braking is a critical design failure that can lead to major accidents and death in the event of engine or transmission failure. There were no warnings, nor instructions or ability to get the car off the road.

On January 16, 2026 our 2024 GMC Terrain Denali experienced complete loss of power. The car was unmovable from the road, unable to shift into neutral, and unable to release the braking system in addition to the emergency brake. There were no warnings or indications prior to the vehicle's failure at 30,000 miles. The failure happened on a somewhat busy road with no ability to move the car out of the line of higher speed traffic. The cause was ultimately determined to be a fuel pump failure. The part was replaced under the 60,000 mile warranty, however, the issue relating got the fuel pump is known by GMC and has previously been litigated under a class-action suit. Therefore the "resolved" fuel pump issue remains a pressing and potentially dangerous and expensive issue.

The screen continues to go out. Screen contains many safety functions. When it malfunctions it is distracting.

While driving the vehicle, the engine light came on, plus message board said service transmission and the engine went into limp mode. We let the car sit for awhile and checked the car. A scan said it was the pressure solenoid A in the transmission. The car sat for a day and the light was off. Drove the car and then it acted up again and now reverse doesn't work.

The contact owned a 2024 GMC Terrain. The contact stated that while her daughter was driving 5 MPH on an intersection, another vehicle driving 40 MPH crashed into the driver's side of the vehicle, by the driver's side door. The driver's side curtain air bag deployed. The contact stated that the three holes on the air bag propelled burning air, which melted and burned through the three layers of clothing of the driver. The driver sustained second-degree burns and blisters on the hip. The contact picked up and transported the driver to Urgent Care, where medical assistance was provided. A police report was filed. The vehicle was deemed a total loss by the police officer. The vehicle was towed to a tow lot, pending assessment from the insurance company. The dealer and the manufacturer were not yet contacted. The failure mileage was approximately 55,000.

See attached document for complaint.

this just started on it's own. back up rear camera shows distortion from time to time and appears to be getting worse or happening more.

The contact owns a 2024 GMC Terrain. The contact became aware of a fluid leak underneath the vehicle. There was no warning light illuminated. The vehicle was driven to a local dealer, where it was diagnosed with a leaking torque converter seal, allowing transmission fluid to leak onto the ground. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was 3,787.

I WAS DRIVING THE CAR ON 12-22-25 I LOST POWER MY CAR DIED ON I94. BATTERY DIED THE DEARLSHIP COULDNT GET THE CODE. GOT THE CAR BACK ON 12-26-25. ENGINE LIGHT CAME ON CARRIE GMC REPLACED BATTERY . CAR BACK ON 12-29-25.. ENGINE LIGHT BACK ON 12-31-25 CAR BACK ON 1-8-26 REPLACLED CATALYTIC CONVEERTED AND OXY SENSOR. 2-20-26 DRIVING ON 1-94 LOST ENGINE POWER CAR BACK ON 2-25 FEUL PUMP AND FEUL LINE. DROVE 300 MILES ENGINE LIGHT BACK ON. BACK TO CURRIE GMC ON 2-26-26 UNTILL 3-2-26 REPLACRED HEATED OXYGEN SENSOR . 3-6-26 REPLACED CATELYTIC CONVERTER AND OXYGER SENSOR FOR THE SECOND TIME.

While driving several times smelt gas and car cut out engine came on and car stopped mid driving multiple times. Says they replaced fuel pump reset car etc

I bought my car in July of 2025 and since then my car keeps derating and reducing engine power while driving down the road at 70 miles an hour. It cuts out and decreases power. I took my car to the shop twice to have them tell it needed an update. I drove away and then the car does it again. Since December my car has down this decreased power, derated notice more than 30 times!! It is a safety risk for me and my family because you never know when it will happen on the interstate and when you will lose power. I have almost been rearended 3 times due to this issue and no one can seem to fix the issue.

Check engine light is coming on, indicating reduced engine power. Took vehicle to GMC dealer and they advised that the repair shop was getting assistance from the GMC Tech line to update a module to correct the issues. I was informed today that the high pressure fuel pump will have to be replaced, along with a hose or pipe to correct the issue. The vehicle has 57k miles on it. Upon researching the issue, I found that this has been a persistent issue with this model vehicle, dating back to 2020. It appears that it has not been resolved and the vehicles could stall or stop at any time. There is currently a class action lawsuit pending on this issue. Please help, this is dangerous

On Febuary 14 2026 I was driving on the feeder of the freeway with speeds of 50 mph my car suddenly down shifted in the middle of driving started shaking real bad stalled wouldn’t start wouldn’t go in gear at all would just die and say engine power reduced. This is after it had just been at the dealership and they said all I needed was an update. It had to be towed and the dealership said it was my high pressure fuel pump had failed. They replaced it and gave me the car back. I staled the next morning going to work on the freeway going 70 mph same exact thing happened except this time I could smell gas so strongly. I had to sit on the side of the highway until it was picked up due to gas smell and fear of fire. They say a bolt broke off of the high pressure fuel pump they just installed