GMC Terrain Complaints

3,167 consumer complaints on file.

#11774393October 29, 2026
SERVICE BRAKES, POWER TRAIN
While driving, I was getting ready to turn into the left lane then I noticed the brake pedal was hard as a rock so I immediately pulled over into a community. I knew it was safe I could barely stop the vehicle because the brake pedal was not giving at all, but eventually, I was able to stop I believe if the terrain wasn’t uphill, I wouldn’t have been able to stop my husband came and assisted with driving the vehicle to the dealership at a very low speed and hazard lights, which was about 20 miles away. This was very scary, but we made it since then the dealership has diagnosed it and it has something to do with brake assist power pump failure, which is documented in a class action lawsuit in Michigan with the same exact problem I’m in the process of getting it fixed down to the camshaft still waiting on final expenses, which I’m sure will be in the thousands we contact the GM to try to get some help with the repairs and they offer us a $350 to help out only if our all change record are acceptable not acknowledging the faulty mechanism power vacuum pump that created all of this
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11773922October 27, 2026
SERVICE BRAKES, HYDRAULIC
The contact owns a 2020 GMC Terrain. The contact stated that while driving 45 MPH, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. The transmission then sputtered. The vehicle was uncontrollable, the brake pedal was depressed; however, the vehicle failed to stop as intended. The vehicle accelerated and drove through an intersection and the engine seized. The vehicle was towed to an independent mechanic where it was diagnosed with vacuum pump failure. The contact was informed that the vacuum pump needed to be replaced. The contact was advised to contact the dealer. The dealer was contacted and made aware of the failure. The contact was advised to contact the manufacturer. The manufacturer was contacted and made aware of the failure. The contact was advised to contact the NHTSA Hotline to report the failure. The failure mileage was approximately 90,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11774027October 27, 2026
ELECTRICAL SYSTEM, UNKNOWN OR OTHER
Infotainment System Crashed
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11773506October 25, 2026
STRUCTURE:BODY, ENGINE, STEERING
Headlights
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11773133October 23, 2026
FUEL/PROPULSION SYSTEM, ENGINE, AIR BAGS
The transmission was jerking and when the heat is running it smells like it’s bout to catch fire
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11773185October 23, 2026
POWER TRAIN
Transmission leak caused but start and stop accumulator
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11773034October 22, 2026
FUEL SYSTEM, GASOLINE
The contact owns a 2018 GMC Terrain. The contact stated that while driving, the vehicle unexpectedly stopped. The contact exited the vehicle and there was an abnormally strong gasoline odor coming from the rear of the vehicle. The vehicle was towed and the tow truck operator stated that there was gasoline leaking underneath the front of the vehicle. The vehicle was towed to an independent mechanic and was diagnosed with high-pressure fuel pump failure. The mechanic referenced NHTSA Campaign Number: 18V358000 (Fuel System, Gasoline); as the possible cause of the failure. However, the VIN was not included in the recall. The contact stated that the “Engine Power Reduced" message was displayed. The mechanic associated the failure with the fuel system. The failure mileage was 92,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11772662October 21, 2026
POWER 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.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11772507October 20, 2026
POWER TRAIN
This car was my daily driver to work it's been serviced regularly and well maintained, in XXX I've had the car for 8 years and driving home from work on the [XXX] it started to Rev very high and I wasn't able to speed up past 55 so I got in the slow lane and the car was not shifting gears and the transmission light came on, I took it to a garage who said the error code was P0700 and I would need a whole new transmission which would cost 8k the trade in value for the 2018 GMC terrain is about that price, having a transmission fail after just 8 years is unacceptable, I've read there is a recall for the transmission in these cars in other states but not in [XXX] where I live 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
#11772027October 19, 2026
AIR BAGS
On 10/1/26 I was in an accident where the entire front of the car was pushed in. The air bags did not employ, which resulted in me hitting my ribs on the steering wheel
Crash:
Yes
Fire:
No
Injuries:
1
Deaths:
0
#11772085October 19, 2026
AIR BAGS, FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING
My husband and I were traveling on the highway doing 75mph. A deer ran out in front of us causing a crash. The front end of the car was extremely damaged and onstar reflects the drivers side air bag deployed (which it sounded like when we hit as we heard a big bang) but no air bag deployed. The car also immediately locked up. The driver stated he could not brake or accelerate and lost all steering. The brake locked up and we went from 75-0 immediately. Thankfully there was not ice on the road as we would have been just full force ahead and thankfully there was no one behind us as they would have totally been in our back seat. Both would have been even worse of an accident then they already were! There was smoke from the brakes (obviously going from 75-0 caused some brake wear and tear) EMT looked at the seat belts as the passengers retracted after she slid forward causing injury to the abdomen. The driver was able to brace a little so not as bad. Insurance is inspecting it today for damage so totality of the damage is unknown at this time. Prior to the Collison the lights warning you of a collision went off but there was no time to react.
Crash:
Yes
Fire:
No
Injuries:
1
Deaths:
0
#11771863October 17, 2026
SEAT BELTS
The driver side seat belt is hard to lock and unlock into the clip. Sometimes it will not lock into the clip.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11771162October 14, 2026
SERVICE BRAKES, ENGINE
On XXX while driving my 2018 GMC Terrain SLE 1.5L turbo on the highway at approximately 70 MPH near [XXX]. I experienced a sudden loss of power brake assist without any prior dashboard warning lights or messages. I was traveling with children to [XXX] for a youth wrestling tournament, approximately 5 hours from my residence. The brake pedal became extremely hard to press, requiring excessive force to slow the vehicle while traveling at highway speeds. I was transporting children at the time, creating a serious safety concern. Because I was away from home and needed to get the children to their scheduled wrestling weigh-ins, I arranged alternative transportation through Enterprise. I was unable to have my vehicle inspected by a GMC dealership until XXX, after returning home. At approximately 93,614 miles, Ed Martin Buick GMC diagnosed an internally failed, engine-driven brake vacuum pump. The service advisor confirmed in writing that the pump had come apart internally and explained that a seized pump can strip the exhaust camshaft gear. The dealership documented missing metal material from the vacuum pump and camshaft gear, raising concerns about metal debris entering the engine. Diagnostic trouble codes included P0014, P0017, and P0556. The dealership estimated repairs at $5,960.79 but advised that the proposed repairs might not remove all internal metal debris. The service advisor stated that replacing the engine would be the only way to guarantee complete debris removal. GM has published technical service information, including PIP5835 and Bulletin 21-NA-268, addressing similar vacuum pump failures and associated damage. The vehicle remains unrepaired. I am reporting this incident because an unexpected loss of power brake assist at highway speeds, without advance warning, creates a significant collision risk for drivers, passengers, and other motorists. 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
#11770963October 13, 2026
ENGINE, SERVICE BRAKES, POWER TRAIN
VIN: [XXX] Mileage: Approximately 103,576 Incident location: [XXX] Safety Complaint: While my wife was driving our 2019 GMC Terrain into a shopping center parking lot, the vehicle suddenly experienced a severe loss of braking assistance. The brake pedal became extremely stiff and difficult to depress, and she was barely able to slow the vehicle. This occurred unexpectedly while the engine continued running, creating a serious risk of a collision. Following the incident, I inspected the vehicle using an OBD-II diagnostic scanner, which identified diagnostic trouble code P0016 (crankshaft/camshaft position correlation). The vehicle also displayed an oil-pressure warning. We subsequently had the vehicle inspected by John's Automotive Care in [XXX] on XXX. During the inspection, the technician discovered a significant amount of metallic debris in the engine oil. The repair facility suspects a mechanical failure of the engine-driven brake vacuum pump, potentially resulting in damage to the engine and lubrication system. The repair facility recommended replacing the mechanical vacuum pump and engine oil-pressure switch and performing an oil change. However, the service representative explained that these repairs would not guarantee the engine's continued reliability because the engine was compromised and could fail at any time. We are extremely concerned that a failure involving the brake vacuum pump could cause sudden loss of braking assistance without adequate warning, potentially resulting in a serious accident. We request that NHTSA investigate whether this failure represents a safety-related defect affecting the 2019 GMC Terrain and other vehicles equipped with similar engine-driven brake vacuum pump systems. 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
#11769667October 7, 2026
ENGINE
Timing Chain driving, clanging noise while driving on I-475 expressway near Perrysburg exit
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11769413October 6, 2026
STRUCTURE:BODY
Tailgate lifts by itself
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11768922October 5, 2026
ENGINE AND ENGINE COOLING
The contact owns a 2014 GMC Terrain. The contact stated that the exhaust manifold was previously replaced due to an exhaust leak and the vehicle was towed. The contact stated that the vehicle was experiencing excessive oil consumption, and a quart of oil was added every 500 to 1,000 miles, causing an abnormal engine ticking sound and timing chain sound. The check engine warning light was illuminated. The contact retrieved DTC: P0420. The vehicle was taken to an independent mechanic, where the timing chain and catalytic converter were replaced; however, the failure persisted. The contact stated that the engine ran rough and experienced reduced power, and the vehicle was idling rough and the vehicle hesitated while accelerating. The contact became aware of an abnormal oil odor during the failure. Additional trouble codes P0017 and P0420 were retrieved. The failure mileage was approximately 65,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11768559October 2, 2026
ELECTRICAL SYSTEM, BACK OVER PREVENTION: REARVIEW SYSTEM BRAKING, BACK OVER PREVENTION: WARNINGS
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 have taken the vehicle to authorized dealerships for multiple service visits and repair attempts. Despite these efforts, the same backup camera failure continues to occur. Although different components may have been inspected, repaired, or replaced during these visits, the recurring problem remains the same: the backup camera display goes black when the vehicle is in reverse. The underlying cause has not been adequately resolved. The vehicle has been presented to authorized GM dealerships for diagnosis and repair, and the relevant service records should document the repair attempts and the recurring complaint. I have also submitted a repurchase request to GM because of the ongoing issue, but my request was declined. I am requesting that NHTSA document and review this recurring malfunction because of the potential safety risk associated with losing the rearview camera image while reversing. I am concerned that this issue could result in a collision or injury if the driver is unable to see a person or obstacle behind the vehicle. I can provide available service records and make the vehicle available for inspection upon request.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11768619October 2, 2026
POWER TRAIN, UNKNOWN OR OTHER
GMC Adaptive learning transmission problems that lead to safety concerns, emissions reduction in MPG, and increased wear of the transmission. Regarding GM’s 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; this casual downshift delay then results in excessive downshifting to the lowest possible gear where the vehicle will then lurch forwards; and then it will pause and maintain said lower gear and continue accelerating for 1-2 seconds while the operator presses the brake pedal in response of the vehicle jumping forwards. Individual situations: 1) Lack of 9th gear use at freeway speeds. This is reducing the advertised emissions based on EPA testing. This behavior skews official EPA test results because vehicle operation is not as advertised. 2) Shift flair and unsafe shift delays. This is the most serious behavior. It leads to pauses and delays in acceleration of up to 5 seconds, and it leads to pauses and delays where the vehicle continues to accelerate up to 3 seconds after letting off the accelerator and pressing the brake. 3) Excessive wear. The badly learned behavior is causing issues with shift control pressure and logic, excessive clutch wear leading to damage and worn clutch packs. Analysis: - Resetting the GM Transmission adaptive learning to factory removes these problems, the trans will relearn bad behavior within 2-3 weeks of daily driving. Reset was performed using an Autel Hot function “Quick Learn” procedure for the transmission.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11768325October 1, 2026
ENGINE, FUEL/PROPULSION SYSTEM, POWER TRAIN
My 2023 GMC Terrain has experienced two separate incidents of complete loss of motive power/engine propulsion while being driven. The vehicle suddenly loses the ability to accelerate and maintain normal propulsion, creating a serious safety risk in traffic. The first occurrence was on August 8, 2026. The vehicle was subsequently diagnosed and repaired by an authorized Chevrolet dealership with General Motors involvement. After those repairs were completed and the vehicle was returned to me, the same loss-of-propulsion symptom occurred again on September 26, 2026, approximately two weeks after the vehicle was returned. The second failure occurred while I was actively driving and again resulted in the vehicle being unable to maintain normal propulsion. The vehicle required towing and is currently at an authorized GMC dealership for diagnosis. The vehicle is available for inspection. This recurring failure creates a risk to the driver, passengers, and other motorists because propulsion can suddenly be lost while the vehicle is operating on a roadway.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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