2020 GMC TERRAIN Complaints

I was driving on the expressway, attempted to brake and the brakes were stiff and would not go down to stop the vehicle. . Thankfully, I was able to glide over three lanes of traffic and exit the expressway and glide into a parking lot and drove around until the car came to a stop. No lights. No warning. The car had to be towed to my mechanic. This could have been catastrophic. I could have killed someone else or myself. This is the second time that this has happened with this vehicle!!! By the grace of God I am still here writing this complaint. I am traumatized and do not feel safe driving this car. They MUST RECALL this vehicle before somebody gets killed. The issue is with the vacuum pump and I have seen other complaints about the same issue.

GMC techs have already documented this issue could not be caused by wear and tear or lack of service - of which there is none the car has been serviced every10k miles as advised. GMC coperate has been contacted case # 71853883 The vacuum pump has failed due to MECHANICAL FAILURE causing it to explode and send pieces into the camshaft. The lack of vacuum caused complete brake failure rendering the car unsafe. GMC is aware of the issue as others habe reported it (I have proof of this) and refuses to recall the cars. The cars loose breaking in the middle of driving with no indicator lights or any other indications. The breaks had just been replaced in may - the incident occurred in October. Has not been driven since.

I was driving on the highway & my brakes failed. My brake pedal was completely hard & could not be used. i had to steer onto an exit ramp & be towed to the dealership. There was absolutely no warning of this happening. Once at the dealership, they confirmed it was my vacuum pump that blew up, which damaged the camshaft & caused pieces of metal to be floating around in my engine. The greater portion of the repair was covered under warranty, however, I had to pay $350 out of pocket. This could have been catastrophic. I or others on the road could have been injure for worse. This system failure should be fixed immediately and owners be compensated. I do not feel safe driving myself or my family in this vehicle after experiencing this occurrence.

During a vehicle accident, my 2.5 year old daughter's car seat detached from the base and landed in the back part of my part. We were t-boned on the passenger side back seat. We spun and the car seat detached and she was flung around the car. She had severe whiplash, a contusion and possible fabric burn on her head. She was buckled in properly and the car seat was properly installed. Yes, all parties (other than manufacturer) saw and inspected the car seat.

I have been experiencing loss of power when going from a full stop to acceleration. I purchased my 2020 Terrain. I almost got in a car accident for the 3rd time today due to this loss of power issue. Stopped at a stop sign, I accelerate but the vehicle will barely move no matter how far down you push the peddle down. The loss of power is anywhere from 4 to 6 seconds then all of the sudden power will return. I've looked for recalls but there are none for my vin. This behavior is unpredictable and has occurred at stop signs, traffic lights, and when attempting to turn onto main roads. It has nearly caused accidents due to my inability to safely accelerate in time when merging or crossing traffic. I’ve read that GMC recalled certain 2021 and 2022 Terrain models for a fuel pump defect causing similar symptoms. My 2020 model is not currently included in that recall, yet it displays the same dangerous loss-of-power issue. I believe this is a serious safety defect that should be investigated and potentially included in the existing recall. I respectfully request that NHTSA investigate this issue further. I would also appreciate confirmation that this report has been logged. Vehicle Info: 2020 GMC Terrain VIN: [XXX] Engine: 1.5L Turbo Mileage: 62,142 Thank you for your time and your work in ensuring vehicle safety. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2020 GMC Terrain. The contact stated while driving 40 MPH the "Brake Assist" warning light illuminated. The contact attempted to depress the brake pedal, but the pedal was stiff. The contact was unable to depress the pedal. The vehicle was taken to a local dealer and unknown repairs were performed. The vehicle was repaired; however, recently the failure reoccurred. The contact stated that the "Brake Assist" warning light illuminated, and the brake pedal was difficult to depress. The vehicle was not taken to a dealer or an independent mechanic to be diagnosed or repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 162,000.

The contact owns a 2020 GMC Terrain. The contact stated while driving at an undisclosed speed, the vehicle lost motive power with the check engine warning light illuminated. The vehicle was towed to an independent mechanic, where it was diagnosed that the fuel pump control module had failed and needed to be replaced. The vehicle was not repaired. The dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure and referred the contact to the NHTSA Hotline for assistance. The approximate failure mileage was 88,000. The VIN was not available.

On 6/22/2025, brakes stopped working while trying to make a turn. Next multiple engines light came and car went into reduced speed mode. As I tried to find a safe place to stop, the vehicle went into limp mode and shut down in the middle of the road. The dealership said the issue was the vacuum pump which caused the timing chains to break. There have multiple recalls for this exact issue but my car is not on the list. My manufacture warranty ended on 5/21/2025. When I spoke to a GM representative I was told there was nothing they can do because there is not a recall for my vehicle. They explained even though I had the same problem the recall is for other vehicles. GM also issued a warranty extention on the vacuum pump to 10 years 150,000 miles. However my vehicle is not on the list for the extention. this issue is a safety hazard regardless of the vehicle type. I was lucky that no one was behind me or they would have hit me.

The contact owns a 2020 GMC Terrain. The contact stated that the vehicle was taken to a dealer for an oil change. The contact stated that approximately 5 weeks after returning the oil change, while driving at approximately 65 MPH, the vehicle and steering wheel started shaking abnormally and the vehicle lost motive power. The contact stated that the traction control, check engine, and stabili-trak control warning lights were illuminated. The vehicle was taken to a dealer where it was diagnosed that there was no oil in the engine and the spark plugs and ignition coils needed to be replaced. The vehicle was repaired; however, the failure reoccurred three weeks later. The manufacturer was not notified of the failure. The failure mileage was approximately 37,000.

While my wife was driving on [XXX] speed (60 –70 mph), the engine suddenly seized without warning. This created a dangerous situation, especially at that speed. Upon inspection, it was confirmed that a camshaft end cap detached, causing catastrophic internal engine damage. I believe this may be due to a manufacturing defect or insufficient part durability, and poses a serious safety risk to myself and other drivers. Please investigate this issue for broader safety concerns and potential recalls, especially if other owners report similar failures. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)