2018 GMC TERRAIN Complaints

The contact owns a 2018 GMC Terrain. The contact stated while driving 45-50 MPH, a message indicating that the engine was not at full capacity was displayed. The vehicle was taken to the dealer, where it was diagnosed that the engine had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 342,000.

The vacuum pump gears for the brake assist was shattered and metal parts were sent into the engine. I lost power brakes and was lucky to be able to stop the suv. The car was towed to a GMC dealer where it was diagnosed with a damaged exhaust cam, a shattered vacuum pump and metal pieces in the motor. Cost to fix $3200. This is a 2018 GMC Terrain with 112000 miles on it. I had a powertrane plus warrenty that was still valid but they refused to pay for anything. They claimed the vacuum pump caused the problem and it was not the engines fault. There were no warning check engine lights before this happened.

The car very suddenly went into a reduced engine power mode, with check engine light and was immediately parked. Figuring I could turn the car off and turn it back on, however it sputtered turning off and shook violently before I was able to turn it off. It would then not turn back over, so I left it off and had a tow truck drive it to a GMC mechanic. The GMC mechanic was unable to diagnose an issue after days. I then had it towed to another local mechanic who stated the parts were "junk" and the engine needed to be replaced. Engine codes were related to the camshaft sensor and brake booster. It is my understanding the vacuum pump broke off into pieces, went into and destroyed my engine.

Vacuum pump is in the shop now being replaced for the 7th time in almost 6 years. The previous one was replaced in September 2023. You get no warning signs, then all of a sudden you can barely press down on the brake pedal. This started within the 1st year of purchase.

I was driving down the highway between 65 and 70 MPH. The semi-truck in front of me almost missed his turn and stopped quickly to make a 90 degree turn off the highway. I went to slow my vehicle appropriately, and my brakes did not respond. I had no warning that my brakes were compromised. I quickly used the downshift button to use my engine to slow me down and I crashed my vehicle off the road into the sagebrush (luckily no trees and there wasn't a dramatic drop off). At that time, after my vehicle came to a stop, I received a warning on my dash that stated "service brake assist". I looked up the issue on my phone to see what may have happened, and read that GMC had a recall for this very issue. I contacted the dealership and they indicated that they were aware that the 2018 GMC Terrain has this issue, but it was not included in the recall. I am traumatized by this incident. I am a very experienced driver, but I had bought this vehicle for my daughter, had she been driving, this would have been a catastrophic accident. I have nightmares about if this had failed when approaching a crosswalk or in a school zone. If GMC is aware of the problem, and they had a full recall on this on other models with this same problem, why aren't they fixing the Terrain, why are they waiting for a fatality. It is unacceptable, dangerous, and I don't even want to know what the cost is going to be to repair the vehicle. I am thankful it wasn't much worse.

Safety was put at risk when brakes went out without warning, and unable to use emergency brake at that time. Car was serviced for over $1700, with the mechanics stating that the piece “blew up.”

The brakes stop working, they get really stiff and locks in the middle of the highway, very hard to stop and almost caused an accident, it is not the first time, the vehicle was serviced by an authorized mechanic and the problem had been resolved until today, the brakes locked and almost caused me to loose control of the vehicles brake system.

The clips popped off or something happened and now the headliner is hanging and I can't see out the rear view mirror. It's a hazard for anyone sitting in backseat. I've had it in 2 different shops .needs to be a recall because I've read several other people having this issue

We were driving back from vacation and while on I-95 the brakes went out. The check engine light came on and the service brake assist light came on. My husband was able to pull off to the side of the road but if it weren’t for already starting to slow down due to an accident we were approaching this could have been much worse. When the brakes went out my husband could hardly press the brake peddle. After researching this appears to be a known issue amongst GM vehicles. It appears to be the vacuum pump that went out. There is an open recall for certain models of GM but not all. This was such a dangerous situation. We literally could have died. This should be a recall for all models as Terrains appear to be largely affected as well from this issue.

While driving on the interstate the brakes all the sudden stopped working. I was able to stop the vehicle by pulling over to the shoulder of the road. I received a warning saying service brake assist and a check engine light after the brakes went out. The vehicle later shut off and is no start with no warning codes. I am currently towing the vehicle to a mechanic. Several people claim to have the same issue online stating that it is an issue with the brake vacuum booster shearing off in the exhaust cam which then causes major damage to the engine. It appears the same issue exists with several other GMC models that were already recalled