*Median odometer reading when the problem happened, where owners gave one. One complaint can name several problem areas.
Electrical system
Infotainment System Crashed
Oct 27, 2026Power train
The contact owned 2024 GMC Terrain. The contact stated that while stopped, the gear shifter independently shifted from drive(D) to park(P). The contact turned off and restarted the vehicle several times and the vehicle operated normally. A dealer was contacted. The vehicle was taken to the dealer to be diagnosed, and it was determined that the transmission needed to be flushed because debris were found inside the transmission. The transmission was flushed and the vehicle was repaired. The manufacturer was notified of the failure and opened a case. The approximate failure mileage was 11,050.
Oct 20, 2026 · 11,050 milesPower train
GMC Adaptive learning transmission problems that lead to safety concerns, emissions reduction in MPG, and increased wear of the transmission. Regarding GMâs 9T45 automatic 9 speed transmission. Problem: - The GM Adaptive learning of the transmission does not have safe guards in place to prevent unsafe sift patterns and behavior. This results in shift flair behavior where the transmission will drop out of 3rd gear and pause before shifting to 4th gear. It will learn to lock out 9th gear and it will max out with 8th gear at freeway speeds reducing MPG. And it will fail to downshift appropriately while driving leading to the operator wondering why the vehicle will not accelerate when needed;…
Oct 2, 2026Electrical system
I am reporting a recurring backup camera malfunction in my 2024 GMC Terrain AT4. Since purchasing the vehicle, I have experienced repeated instances in which the rearview camera display goes completely black when the vehicle is shifted into reverse. This prevents me from seeing the camera image while backing up. The malfunction presents a safety concern because the rearview camera is an important aid in identifying pedestrians, children, objects, and other vehicles behind the vehicle. When the display goes black, I lose that visual assistance, increasing the risk of backing into a person or object, particularly in parking lots, driveways, and other areas where pedestrians may be present. I…
Jun 24, 2026Steering
The Electric Power Steering (EPS) gear assembly / rack and pinion failed completely. Yes, the component is available for inspection upon request; it is currently located at the servicing dealership. A total failure of the steering gear assembly caused immediate loss of power steering assist, making the vehicle extremely heavy, rigid, and difficult to steer or control. This sudden mechanical/electronic failure puts the driver, passengers, and other motorists at extreme risk of a collision, especially if it occurs at highway speeds or while negotiating a turn. This did fail on me driving down the Highway! Yes. The problem was officially diagnosed and confirmed by the franchise dealership.…
Sep 13, 2026Power train
Factory powertrain programming actively locks out 9th gear (overdrive) during freeway driving at speeds exceeding 60â65 mph. The vehicle refuses to upshift from 8th to 9th gear, forcing sustained high-RPM operation during standard highway cruising.
Sep 1, 2026Unknown 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 couldnât close.
Jul 23, 2026Forward collision avoidance › Warnings
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.
Jul 13, 2026
Owner complaints are submitted to NHTSA by the public and are not verified. Shown as filed (NHTSA removes personal details); long reports are shortened.