2020 GMC Terrain

197 complaints on file, page 1 of 10.

1. Filed Sep 29, 2026Failure Sep 15, 2026Bristol, CTService brakes

   While driving at the speed limit the vacuum pump failed on my 2020 GMC Terrain. This failure led to me enter an intersection with heavy cross traffic, nearly striking g several vehicles. This is the 3rd time I have had to replace this pump in 2 years. The pump explodes sending chards of metal into the engine leading to more damage and labor intensive work.

   NHTSA complaint 11767839
2. Filed Sep 23, 2026Failure Aug 29, 2026Greenville, NCEngine, Power train, Service brakes

   While driving my 2020 GMC Terrain, I experienced a sudden loss of normal braking assistance. I had been traveling on the highway and exited onto a main road. As I approached a red traffic light at approximately 50 mph and attempted to brake, the vehicle would not stop normally. I was unable to stop for the red light and went through the intersection before I was able to safely get the vehicle off the roadway. Fortunately, there was no vehicle directly in front of me and I was able to make it through the intersection before any other cars, so no collision occurred. The vehicle was subsequently inspected and diagnosed by a GMC dealership. A diagnostic scan performed after the incident showed code P0556 for the brake booster pressure sensor circuit range/performance. The GMC dealership later diagnosed problems involving the vacuum pump, exhaust camshaft, and timing components and recommended replacement of the vacuum pump, exhaust camshaft, timing components, and related parts.” The sudden loss of braking assistance created a serious safety hazard and could have resulted in a collision, serious injury, or death. The vehicle is currently available for inspection.

   NHTSA complaint 11766529
3. Filed Sep 8, 2026Failure Dec 17, 2021Leming, TXEngine, Power train

   Having the start stop issue on my terrain and recently over the last few months, it has been using oil everything that sounds exactly like the recall but mine is not included. My start stop is not working and I have to get him since it had only 60,000 miles on it years ago, but nothing was done.

   NHTSA complaint 11762749
4. Filed Sep 2, 2026Failure Sep 2, 2026Windsor, OHFuel/propulsion system

   Fuel pump control module and or the in tank fuel pump failed and or isn’t making proper connection for car to run correctly. Safety was put at risk as car came to abrupt halt while driving. Driver was outside of vehicle at busy intersection for vehicle diagnostics and battery jump. Battery was removed and new battery installed yet problem persists. Not confirmed by dealer but code is as follows (p129F). Maintenance performed by owner;Code reader used for diagnostics, new battery installed. Problem persists. Car started, drove and stumbled to then die. Check engine now displays.

   NHTSA complaint 11761691
5. Filed Aug 31, 2026Failure Aug 24, 202692,000 milesNewburg, ORService brakes, Hydraulic

   The contact owns a 2020 GMC Terrain. The contact stated that while driving at an undisclosed speed, the vehicle failed to stop as intended. The brake pedal was depressed to the floor, and the vehicle slowed down and eventually stopped. The vehicle was taken to an independent mechanic, where it was diagnosed with a failed vacuum pump. The mechanic informed the contact that the vacuum pump needed to be replaced. The vehicle was repaired. The contact stated that the failure was a known issue with the vehicle. The manufacturer was not notified of the failure. The failure mileage was approximately 92,000.

   NHTSA complaint 11760902
6. Filed Aug 24, 2026Failure Aug 19, 2026Rochester, MNFuel/propulsion system

   COMPONENT OR SYSTEM FAILED - GMC Dealership replacing fuel pump. SAFETY OR SAFETY OF OTHERS AT RISK - stalled in remote area with no internet/cell service. In order to get to safety we travelled 13 miles of narrow 2 lane roads with no shoulder or escape areas. Road included 3 miles of a steep downhill grade. HAS THE PROBLEM BEEN REPRODUCED OR CONFIRMED BY A DEALER - Yes, Walser GMC [XXX] WERE THERE ANY WARNING LAMPS, MESSAGES OR OTHER SYMPTOMS OF THE PROBLEM PRIOR TO THE FAILURE - No, drove 400 miles w/2 stops, rest stop and lunch/gas. Got to our destination, shut off the car. Needed to move the vehicle to designated parking spot and at first the vehicle would not start, got it started but lurched forward, engine chugged, no acceleration and then stalled. Waited 10 minutes vehicle started with same symptoms but became drivable so we headed to safety 13 mile to nearest town, [XXX]. The area has recently been battling forest fires and in our area, although "safe", there was still HIGH fire danger. We did not feel safe w/o a vehicle for (possible) rapid escape. The city has limited services, no rental car company, no Uber/Lift, closest car dealership 90 miles away. Vacation cancelled. Hired North [XXX] Towing to transport vehicle and people 300 miles to Walser [XXX], [XXX]. Family member drove us to our home in [XXX]. To date vehicle mileage - 30,000 miles! INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

   NHTSA complaint 11759075
7. Filed Aug 23, 2026Failure Aug 23, 2026Mikado, MIService brakes

   The brake suddenly became impossible to depress more than 3/4 of an inch. Almost unable to stop nearly hitting another vehicle. The dashboard then lit up with a "service brake system" warning. Luckily was only a few minutes from home brought it home and began the search for the issue. The brake vacuum pump failed. Unsure of further damage at this point. It being Sunday am unable to contact a shop or dealer.

   NHTSA complaint 11758896
8. Filed Aug 19, 2026Failure Aug 19, 2026Middletown, CTEngine, Service brakes

   While driving, I suddenly smelled something burning. Immediately after, a warning popped up stating 'Engine power is reducing,' the check engine light came on, and I experienced a sudden, near-total loss of power braking assist, making the brake pedal extremely hard to press. I had to use intense force to bring the vehicle to a stop. A scan of the vehicle's OBD-II codes revealed codes P0556 (Brake Booster Pressure Sensor Circuit), P0014 (Exhaust Camshaft Position Timing Over-Advanced), and P0017 (Crankshaft Position - Camshaft Position Correlation). This is a known failure where the engine-driven mechanical brake vacuum pump seizes up, destroys the braking vacuum assist, and bends or shifts the exhaust camshaft reluctor wheel, causing a severe and immediate safety hazard while in motion.

   NHTSA complaint 11757862
9. Filed Aug 13, 2026Failure Aug 6, 2026Wappingers Falls, NYUnknown or other

   During heavy rain, the sunroof on my Terrain leaked badly enough to allow a substantial amount of water into the vehicle. The rear floor area became completely saturated, and the sunroof controls stopped working. I brought the vehicle to Hudson Cadillac Buick GMC in Poughkeepsie, New York, to have the problem diagnosed and repaired. The resulting repairs and water-damage cleanup cost me nearly $3,000 out of pocket. I was advised that the damage was not covered by my warranty or by my insurance. What concerns me most, however, is that this does not appear to have been an isolated incident. While my Terrain was at the dealership, I learned that four other GMC Terrains were also at the dealership experiencing water damage related to leaking sunroofs. Mine was the fifth. Finding five Terrains at the same dealership with what appeared to be similar water-intrusion problems was extremely concerning to me and made me question whether this is a recurring issue with these vehicles. I also have a video provided by the dealership documenting the water damage to my vehicle, and I am happy to provide that video, my repair invoice, photographs, or any other documentation you would like to review. They went to great lengths to dry the vehicle, which was especially important to me because I was extremely concerned about hidden moisture and dangerous mold. Thankfully, after their work, there is no odor and no indication of remaining moisture or mold, and I am very satisfied with the quality of the repair and cleanup. The extent of the water damage was frightening. At one point, I was genuinely concerned that I might have to get rid of the vehicle simply because I was afraid of the long-term consequences of having so much water inside it. I am very grateful that the dealership was able to restore the vehicle so thoroughly but there is still a possibility that the repair will fail and I will have to replace the sunroof module.

   NHTSA complaint 11756698
10. Filed Aug 7, 2026Failure Jul 25, 2026Windermere, FLFuel/propulsion system

    While driving home from work my 2020 GMC Terrain stalled and turned off. I was on a very busy 2 lane road, crossing a intersection in a tourist area in [XXX]. This could have be come fatal very easily. I was able to get the car started and Home but had to take it very slow. Next day we weren't able to get the car started nor turned on. Battery is new and still works, we also had a mechanic come to the house and run his computer telling us it was the Fuel Pump Control Module. There were no warning signs leading up to this moment. I see there has been recalls for the same issue for 2021 and 2022 models but my GMC dealership I bought my car at is telling this isn't an issue in any Terrain that they are aware of. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

    NHTSA complaint 11755525
11. Filed Aug 6, 2026Failure Aug 6, 2026Paducah, KYUnknown or other

    When the gas is mashed to accelerate, the car does not want to go. It has left me stranded and rolling in the middle of traffic. I am scared to drive it.

    NHTSA complaint 11755351
12. Filed Aug 5, 2026Failure Jul 30, 2026Bonneau, SCFuel/propulsion system, Power train

    Because of the intentional failure of GMC and there promise of “We are Professional Grade”, I almost got plowed down by a semi when the car began to quit on the highway going 60. After pulling into the next driveway, which happened to be a Parker’s Kitchen, and ending up on the curb spot, thanking God I wasn’t dead, I sat there for a moment wondering what just happened. As I went to restart the car, it wasn’t having any of it. 40,000 miles, not professional grade GMC, circus grade. Towed it to my home, figuring it has to be something minor and a diy fix. Bought the hyper-tough code reader delivered by Walmart and it delivered professional grade results: U18A2, P1787 and P187E. I am beyond pissed. I could have died due to your intentional negligence in manufacturing. I have a car that will not start, with payments. I have searched the internet and found your “save ourselves plan” and let’s do a voluntary recall starting with 2021 on the same failed parts I am dealing with at the moment. Thanks GMC, who is the ringleader of your circus?

    NHTSA complaint 11755143
13. Filed Jul 30, 2026Failure Jul 20, 2026Mercer, PAService 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.

    NHTSA complaint 11753729
14. Filed Jul 23, 2026Failure Jul 9, 2026Nashua, NHEngine, Service brakes

    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.

    NHTSA complaint 11752293
15. Filed Jul 18, 2026Failure Jul 17, 2026High Point, NCElectrical system, Seats, Unknown or otherFire

    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.

    NHTSA complaint 11751287
16. Filed Jul 18, 2026Failure Jul 16, 2026New Athens, ILService 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.

    NHTSA complaint 11751242
17. Filed Jul 10, 2026Failure Jul 9, 2026Maysville, GAFuel/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.

    NHTSA complaint 11749649
18. Filed Jul 9, 2026Failure Apr 20, 2026Strykersville, NYEngine and engine cooling

    See attached document for complaint.

    NHTSA complaint 11749358
19. Filed Jun 21, 2026Failure Jun 15, 2026Walworth, NYRearview system braking, Warnings, Unknown or other

    Backup camera stopped working and displays a blue screen stating “service backup camera.” This was an issue when the vehicle was under 3 year manufacturer bumper to bumper warranty and was fixed by dealer at no cost. Now this same issue has occurred again approximately 3-4 years later. I thought at first this was an issue specific to my vehicle but now after doing research I see this is an issue across several GMC Terrian vehicles and other GM vehicles. This issue should be fixed by the manufacturer for all vehicles affected. Vehicle owners should not be responsible to fix faulty parts from the manufacturer.

    NHTSA complaint 11745463
20. Filed Jun 17, 2026Failure May 23, 202646,917 milesChicago, ILFuel system, Fuel pump

    The contact owns a 2020 GMC Terrain. The contact stated that shortly after refueling the vehicle, the vehicle suddenly stalled while accelerating from a stop light. The contact stated that after the vehicle stalled, the transmission failed to shift out of park, and the vehicle failed to restart. The vehicle was later towed to the local dealer to be diagnosed. The vehicle was diagnosed with fuel pump failure. The fuel pump was replaced, and the vehicle was repaired. The manufacturer was not yet contacted. The failure mileage was 46,917.

    NHTSA complaint 11744805