What are the most common problems on the 2021 GMC Terrain?

NHTSA has 34 owner complaint(s) on record for the 2021 GMC Terrain. Engine is the most-reported problem area on the 2021 GMC Terrain, cited in 8 of 34 filed complaints (24%).

Problems › GMC › 2021 Terrain

2021 GMC Terrain Problems & Owner Complaints

34 NHTSA owner complaints

4 crash 4 injury

Age-normalised, this year draws ~5.7 complaints per year on the road — ranking 15 of 15 GMC Terrain years we track (1 = most complaints per year).

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What owners report

Engine is the most-reported problem area on the 2021 GMC Terrain, cited in 8 of 34 filed complaints (24%).

Power Train is next (8 complaints, 24%), followed by Service Brakes (8), Electrical System (7), Forward Collision Avoidance (3).

Across all complaints, 4 report a crash, 4 report injuries.

The most safety-critical cluster is Service Brakes: 2 crash, 2 injury report(s).

Complaints by vehicle system

Owner complaints filed with the U.S. NHTSA for the 2021 GMC Terrain, grouped by the vehicle system each cites. A single complaint can name more than one system, so the group totals can add up to more than 34.

Engine 8

“Vehicle went into reduce engine power mode and check engine light came on. Vehicle has just over 60,000 miles. Code is telling me I need a new turbo and being quoted 1,500-3,000. I have read so many people having the same issue with needing a new turbo just after 60,000 miles”
NHTSA complaint #11724745, 2026

“The engine light came on while driving, saying “engine power reduced”. It barely accelerates, RPMs go over 5, it chugs when driving. Taken to an independent service center.”
NHTSA complaint #11713477, 2026

“The contact owns a 2021 GMC Terrain. The contact stated that while driving at various speeds, the vehicle hesitated while depressing the accelerator pedal, with a misfire coming from the engine. During the failure, the message "Engine Power Reduced" was displayed on the instrument panel. The vehicle was taken to a local dealer, and the contact was provided an estimate for a diagnostic test. The contact declined. The vehicle was not repaired. The manufacturer was not contacted. The failure mileage was unknown.”
NHTSA complaint #11724576, 2025

Power Train 8

“Automatic transmission solenoid control valve body got stuck open and ruined the whole transmission. This has been a reoccurring problem with these vehicles. Image is from a code read. Issue was confirmed by Gastorf Chevrolet, and an independent transmission shop.”
NHTSA complaint #11734629, 2026

“The contact owns a 2021 GMC Terrain. The contact stated that the transmission was previously replaced. The contact stated that upon starting the vehicle, the check engine warning light illuminated. The failure had occurred intermittently. Additionally, the contact stated that while driving approximately 15-20 MPH and depressing the accelerator pedal, the vehicle failed to respond for approximately 1 minute. The vehicle was taken to the Nissan dealer it was purchased several times. The dealer retrieved diagnostic trouble codes: P057C and P057E, and the brake pedal position sensor was replaced t…”
NHTSA complaint #11687881, 2025

“The contact owns a 2021 GMC Terrain. The contact stated while driving at various speeds, the transmission erroneously shifted to the neutral, causing the vehicle to decelerate. After restarting the vehicle, the vehicle operated normally. During the failure, the message " Power Reduced" was displayed. The cause of the failure was not yet determined. The local dealer was notified of the failure. The vehicle was not repaired. The manufacturer was not contacted. The failure mileage was 36,000.”
NHTSA complaint #11656552, 2025

Service Brakes 8 2 crash 2 injury

“The contact owned a 2021 GMC Terrain. The contact stated while the brake pedal was depressed, it was released and the vehicle suddenly accelerated aggressively. The contact attempted to avoid crashing into the vehicle in front and swerved however the front of the vehicle still impacted the vehicle in front. The air bags deployed upon impact. A police report was filed. The contact stated no medical attention was provided, but did suffer bruises from the air bag and seat belt. The vehicle was towed to an independent mechanic. The dealer was not contacted. The vehicle was not diagnosed or repaire…”
NHTSA complaint #11612312, 2024 · crash · 1 injury(ies)

“i WAS GOING TO MY SONS HOME WHICH IS LOCATED ON A STEEP DOWHILL STREET WITH SEVERAL TURNS, ONE OF THER ALMOST 90 DEGREES.aS i STARTED TO DESEND THE HILL AND GAIN SPEED, I DEPRESSED THE FOOT BRAKE. iT DID NOT RESPOND AT ALL. AS I CONTINUED TO GAIN SPEED AND COMING UP ON THE SHARP CURVE, I CONTINUED TO PUMP AND APPLY BRAKE . tHE BRAKES DID NOT WORK. i CONTINUED TO GAIN SPEED AND GO AROUND 2 OTHER TURNS. AT THE END OF THE STREET i HAD A CHOICE TO CONTINE STRAIGHT AHEAD AND HIT A HOUSE, TURN RIGHT AND CONTINUE DOWN ANOTHER STEEP STREET UNTIL I HIT A HOME AT THE END OF THE STR…”
NHTSA complaint #11431951, 2021 · crash · 1 injury(ies)

“Vacuum pump failure caused my brakes to lock up and almost caused me to wreck into another vehicle”
NHTSA complaint #11749838, 2026

Electrical System 7

“Driving my vehicle with no warnings, messages, or symptoms on adaptive cruise control Sunday [XXX] on [XXX] in Michigan. I changed lanes into the right lane when the vehicle abruptly, without notification, and with force, caused braking that unexpectedly and dangerously slowed the vehicle then released braking before doing the same a moment later. Vehicle was pulled off the road onto the shoulder without an accident, thankfully nobody was behind because they would not have been able to stop in time before hitting my vehicle and I assume the brake lights weren't activated since I did not press…”
NHTSA complaint #11670483, 2025

“I purchased the car August 2024, I have had it for 4 months and while driving down the road a large fuel tank pops up stating low fuel and the car comes to an abrupt stop.The 3x the gas tank was never low. Parking brake comes on and car doesn't not move. All lights on dash come one. It has done it 4 times and thankful each time I was in a 30 mph zone. If I was going 55 I am sure the result would have been bad. The car last did it on December 29, 2024 and has been in the dealership for 3 weeks now and they cannot fix it. I told them 3 days into my purchase I wanted a full refund and they denied…”
NHTSA complaint #11635970, 2024

“The car has revved high rpm's since purchase, with multiple attempts to get it resolved . Since then, the steering wheel has jerked out of my hand's multiple times, unexpecting, causing the car to jerk while being stopped. The car has also not budged in the middle of traffic while being in drive and the pedal down to the floor until at least a 10 second delay and when doing so the screen that includes the radio, etc panel has completely blacked out and started twitching”
NHTSA complaint #11574021, 2023

Forward Collision Avoidance 3 1 crash 1 injury

“Automatic Emergency brakes have unnecessarily or prematurely activated on 2 separate occasions causing my car to stop very abruptly which has resulted in Neck, Shoulder and back pain. I have been very lucky in the recent past and today that a vehicle was not directly behind me. The seat vibrated first when it sensed the car ahead was breaking. When I started to break, the emergency break kicked in. I did not report this the first time because I thought the car was doing what it was supposed to do. Today was unnecessary. No accident and no police report. I do plan on telling the dealership.”
NHTSA complaint #11537561, 2023 · 1 injury(ies)

“I was backing out of a parking spot when I came in contact with a vehicle going east bound in the parking lot the contact was on the rear right side of my vehicle before I could do anything my vehicle sped up and proceeded to go forward jump a curb I had my foot on the brakes when I realized I wasn’t stopping and heading for a garage I turned right trying to avoid the garage but still hit the corner of garage causing damage then vehicle stopped and shut down.The Vehicle is still being repaired the mechanic said there was damage to a box and cable going to transmission but couldn’t say if it wa…”
NHTSA complaint #11522061, 2023 · crash

Unknown Or Other 3

“Constantly have water leaking into spare tire compartment, back seat floors and passenger floor. Mold/mildew smell coming through vents. Have had drains lines cleaned out, and still recurring having this issue. Unknown where leak is coming from. This is a serious health risk.”
NHTSA complaint #11678054, 2025

“Drive shaft on my GMC Terrain needs to be repaired according to my repair shop. I brought it in as it was vibrating on acceleration and other times frequently. I was told it was the “drive shaft” and the mechanic states they have had Equinox and GMC Terrains coming in for same issue. (Specifically my year Terrain) I looked up and found this recall # for this issue: N212343560. I was never notified and now have a very expensive repair bill which may or may not fix the issue.”
NHTSA complaint #11660584, 2025

“There is a rattle in the b pillar/roof area. They have attempted to fix it 4 or more times by adding adhesive between layers of metal. The fix that other dealerships have done per reading online involves cutting through metal. This would affect the integrity of the body/ frame of the car.”
NHTSA complaint #11478411, 2022

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Engine And Engine Cooling 2

Fuel System 2

“The contact owns a 2021 GMC Terrain. The contact stated while driving 5 MPH, the vehicle stalled. There was no warning light illuminated. The contact stated that the failure was like GM Product Safety Recall: N222372310 (Inadequate Fuel Pump Flow). The vehicle was towed to an independent mechanic, who determined that the fuel pump had malfunctioned and damaged the camshaft. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not contacted. The approximate failure mileage was 86,000.”
NHTSA complaint #11652800, 2025

“The contact owns a 2021 GMC Terrain. The contact stated upon pressing the Push to Start button, the vehicle failed to start after several attempts, and the battery drained. The vehicle was towed to the dealer, but the failure could not be duplicated. The contact stated that the vehicle restarted after a while. The check engine warning light was illuminated. The contact stated that the failure recurred intermittently. Additionally, the contact stated that the vehicle stalled while at a complete stop at a traffic light. The contact also stated that the vehicle stalled while driving on two separa…”
NHTSA complaint #11543018, 2022

Fuel/Propulsion System 2

Lane Departure 2 1 crash

Suspension 2

“First time I had problems with my 2021 Terrain I took it to victory GMC on 9/20/24. At the it had 45,000 miles. Every time I would drive and accelerate it would shake extremely bad in the floorboard. There was also transmission fluid leaking. I picked the car up on 9/27/2024 and was advised that both front axles were replaced, which corrected the shaking and the driver side axle seal was replaced, which was where the leak was coming from. this was covered under warranty but at 45,000 miles I should not have been already having axle problems or any type of leak. I dropped my car off again on Ma…”
NHTSA complaint #11663450, 2024

“Just purchased this vehicle has about 64500 miles on it. When accelerating between 40-55 (hard acceleration) my vehicle wobbles really bad, seems like a tire issue. Have had the front end looked at, and tires all balanced and inspected. Noting out of the ordinary. Then all of a sudden my rear view back up camera works, but my back up assist symbols are not showing/working. I checked the settings and they are turned on. To top off the cake, when the weather is cold outside my windshield wiper fluid will not spray from the front windshield or rear, then when it warms up or is parked in a garage…”
NHTSA complaint #11507301, 2023

Air Bags 1 1 crash 1 injury

“I was in a in a 70 miles an hour highway accident and was hit in front driver side door, went up embankment and hit a tree then rolled backwards onto the highway. No airbags deployed.”
NHTSA complaint #11568581, 2024 · crash · 1 injury(ies)

Child Seat 1

“The contact owns a 2021 GMC Terrain. The contact received notification of NHTSA Campaign Number: 23V339000 (Child Seat); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The dealer was contacted and informed the contact that the vehicle would not be inspected or repaired. The manufacturer was made aware of the issue. The contact had not experienced a failure.”
NHTSA complaint #11696797, 2023

Steering 1

Vehicle Speed Control 1 1 crash

Visibility/Wiper 1

How we read this (methodology)

How to read this: raw complaint totals are not a clean reliability score — a model year with more cars sold, or simply more years on the road, accumulates more complaints regardless of how good it is. So this page leans on two signals that are not distorted by sales volume: the share of complaints falling on each vehicle system (the breakdown above) and NHTSA's own crash / fire / injury / death flags. When we compare model years of the same model, we normalise by years on the road (complaints ÷ vehicle age) rather than comparing raw totals. Age-normalised, the 2021 GMC Terrain draws about 5.7 complaints per year on the road, ranking 15 of 15 among the GMC Terrain model years we have ingested (1 = most complaints per year on road).

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Data source: U.S. NHTSA (nhtsa.gov). SaveVIN surfaces public recall data and is not affiliated with or endorsed by NHTSA.