2021 GMC Terrain Recalls, Ratings & Complaints

Incident: May 27, 2026 · Filed: September 29, 2026

I have had my check engine light come on for P0299. I've lost power while on the road. Had my turbo replaced and now the same issue is starting again. I'm afraid of my car stalling out again with my child in the car. This is a definite safety issue especially since this is happening again months after getting the new turbo put in.

Incident: July 22, 2026 · Filed: September 11, 2026

Vehicle Information:Year/Make/Model: 2021 GMC TerrainEngine Type: 1.5L Turbocharged EngineCurrent Mileage: 155,000 miles [1]Description of Safety Defect:I am writing to report a severe, sudden engine and turbocharger failure on my 2021 GMC Terrain that presents an extreme, life-threatening safety hazard. While operating the vehicle in active traffic, the engine began flashing a severe dashboard warning reading "Stop Now Danger" (accompanied by low oil pressure alerts) before suffering an immediate, catastrophic loss of all motive power. 2-This unexpected stalling leaves the driver completely stranded on active roadways without warning, drastically expanding the risk of a high-speed rear-end collision. A mechanic has inspected the vehicle and confirmed that both the engine assembly and the turbocharger require full replacement, with a repair estimate totaling 12,000. General Motors is currently facing legal actions regarding defective, camshaft-driven mechanical vacuum pumps and PCV configurations on these 2018–2022 1.5L engines defects known to fracture, send metal fragments violently into the engine top, and trigger immediate engine failure and turbocharger destruction. Despite these severe risks, GMC has refused to provide any goodwill assistance or repairs because the vehicle is outside warranty. I request that NHTSA immediately investigate the engine-destroying defects inherent to the 2018–2022 GMC Terrain line to protect consumers from catastrophic highway power failure.

Incident: July 12, 2026 · Filed: July 12, 2026

Vacuum pump failure caused my brakes to lock up and almost caused me to wreck into another vehicle

Incident: June 28, 2026 · Filed: July 1, 2026

Formal Safety Complaint – 2021 GMC Terrain Brake Failure Vehicle: 2021 GMC Terrain Incident Location: Garden State Parkway (NJ) Speed: Approximately 65 mph Incident Description While driving northbound at highway speed, I attempted to change lanes and apply my brakes. When I pressed the brake pedal, it became completely rigid (rock hard) and failed to function. I had no ability to slow the vehicle using normal braking. At that moment, I was forced to: Navigate multiple emergency lane changes to avoid striking other vehicles Prepare for potential collision due to lack of braking control Apply extreme force with both feet on the brake pedal in an attempt to generate any slowing Eventually, I was able to steer the vehicle to the shoulder while exerting maximum pressure on the brake pedal. During the incident, a “Driving Assist Brake” message appeared on the dashboard, and the braking system has remained in this same compromised condition since. Safety Concerns The brake pedal became non-functional without warning The failure occurred at highway speed, creating an immediate life-threatening situation This was not a gradual degradation—this was a sudden, complete loss of braking capability The issue persisted after the vehicle was stopped Broader Concern I have since found multiple reports and videos of other GMC Terrain owners experiencing the exact same failure, suggesting a potential systemic or design-related issue. Given: The severity of braking system failure The apparent repeat nature of this issue The lack of an active recall addressing it I believe this represents a significant safety risk to GMC Terrain drivers and the public. Impact This incident caused: Immediate danger to my life and other drivers Extreme emotional distress Loss of confidence in the safety of the vehicle Requested Action I am requesting: A formal investigation into this braking failure Immediate inspection and repair of my vehicle at no cost Clarification from GMC regarding know

Incident: June 28, 2026 · Filed: July 1, 2026

Driving on the Garden state parkway on Sunday night June 28, 2026 I proceed to cross over the ratitan bridge. There was traffic as I was going down the bridge at 70 miles an hour. When I applied the brakes the car would not stop. I had two 6 years old in the backseat. I applied 2 feet to the brake pedal and it was like a rock and the car would not slow down. I thought I was going to crash. I had to steer and lane change several times to avoid hitting other cars. This has something to do with the driving assist braking system. I was scared to death. If this isn’t a safety concern nothing is. This should be a recall for GMC to fix because it’s an accident waiting to happen.

Incident: April 13, 2026 · Filed: April 29, 2026

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.

Incident: February 13, 2026 · Filed: March 16, 2026

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

Incident: August 1, 2025 · Filed: March 16, 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.

Incident: January 26, 2026 · Filed: January 26, 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.

Incident: December 24, 2025 · Filed: January 22, 2026

around chirstmas, Was driving on the highway and the car threw a "reduced engine power" warning and went into limp mode. Check engine light came on. Car asymptomatic prior. got the code pulled and it said turbocharger under boost. The next day the check engine light went out and car was running appropriately. Took the car on the highway again and the car threw the "reduced engine power" warning and went into limp mode again in the middle of freeway traffic. It is a safety concern due to the engine going into limp mode in the middle of high speed traffic. I easily couldve caused an accident putting both myself and others in danger by the engine cutting the power in the middle of the freeway. The check engine light only comes on while going at freeway speeds. The light will then go out overnight and come back on the next time i go back on the freeway at 70-80mph speeds. I have taken it to one shop which reported an oil leak coming from the turbo both inside and outside and that it needed to be replaced. I have read several different forums of other users of the same year, make, and model experiencing the same issue. the car is only a few years old and the likelihood of a turbocharger being bad is uncommon but a major safety concern considering this happened out of nowhere with no signs or symptoms leading up to this.