2018 GMC TERRAIN Complaints

Component Affected: Service Brakes, Hydraulic – Brake Vacuum Pump Summary of the Problem: I am reporting a serious safety issue involving the brake vacuum pump on my 2018 GMC Terrain. The brake pump failed catastrophically ("blew up"), resulting in a sudden loss of braking power. This occurred without warning and posed a significant risk to my safety and others on the road. We were traveling to vacation in Florida and thankfully had just gotten off the interstate. Details: The failure caused the brake pedal to become extremely hard to press, and the vehicle required a much longer distance to stop. We experienced no brake at the brake booster and a blown vacuum pump is due to a faulty vacuum pump which is a known issue for this model. Fortunately, no accident occurred, but the situation could have easily led to a collision. A certified mechanic confirmed that the brake vacuum pump exploded and needs to be replaced. I have incurred significant out-of-pocket repair costs due to this issue. We had to uber to our vacation room, get Walmart Plus to have groceries delivered to our room. We had to have Uber Eats deliver other supplies. We have had to walk to various places for dinner and entertainment because Avis and Budget had no vehicles available to rent and Enterprise was closed as we arrived on Saturday afternoon. I have checked for recalls and service bulletins using my VIN, but none are currently listed for this specific issue, despite similar problems being reported in other GM vehicles. Request: I urge the NHTSA to investigate this issue further. The failure of a critical braking component without warning is a serious safety concern. I believe this may be part of a broader pattern of brake system failures in GM vehicles and should be addressed through a recall or safety campaign. Also, the estimate for the repair is $2,500 so any reimbursement would be greatly appreciated. We just received this estimate but I can provide it at a later date.

Broken piston land and ring. car went into 'limp mode' while driving on interstate. Taken to dealer, told new engine was needed.

My car started experiencing a strange problem while braking on June 15. I released the parking brake leaving my parents driveway. I coasted backwards (as usual), and when I pressed the brake the car didn't stop as expected and the brake pedal was very hard to press. It eventually stopped. I put into park, then put the emergency brake on, then released all and tried again and encountered the same issue, that it was very very slow to stop and the brake pedal was hard to push in. I got home, parked the car - tested the reverse brake on flat surface and didn't notice the issue. The next day, the problem started happening with the front brake as well and an error code popped up that said 'check brake assist' which I've never seen before. I brought it to my local mechanic, who took a look and said that it's a vacuum pump failure, and the result is a lot of metal shards were released into the engine when the vacuum pump failed. My mechanic recommended I take to a GMC dealer for further evaluation. I looked up the recall on this issue, and see that it impacts a lot cars, including the 2017 GMC terrain, but not my 2018 GMC terrain. I am going to take it to the GMC dealer but I'm afraid I won't be able to afford the repair, and it doesn't seem like there was anything I could have done to prevent this from happening.

The contact owned a 2018 GMC Terrain. The contact stated that while driving and nearly coming to a complete stop in the right lane, another vehicle driving approximately 40-50 MPH crashed into the rear of the vehicle, causing the contact to hit her face against the steering wheel, and the contact became unconscious temporarily. The contact stated that upon regaining consciousness, the contact noticed that the vehicle had moved to the grass by the left lane of the road, where traffic was going in the opposite direction. It was unknown whether the vehicle was involved in a second collision. A message advising that an accident was detected and inquiring whether 911 should be contacted was displayed. The contact stated that the air bags failed to deploy, and the front driver's side seat belt failed to retract as needed. A bystander opened the driver's side door to verify that the contact was safe. The contact noticed that she was bleeding significantly and was unable to move the right shoulder and the neck. The emergency units assisted the contact out of the vehicle. The emergency units placed braces on the contact's neck and placed the contact on a stretcher. The contact was transported to the hospital, where the contact underwent X-rays and CT scans. The contact was informed that she had sustained a concussion, lumbar injuries, a fractured nose, loss of taste and smell, laceration on the inner and outer side of the bottom lip, carpal tunnel on the right hand, severe whiplash, laceration on the right shoulder, and a cut behind the right ear. The contact was in the process of undergoing MRIs. A police report was filed. The vehicle was towed and totaled, but was still under investigation. The dealer was not notified of the failure. The manufacturer was notified of the failure, and a case was filed; however, no further assistance was provided. The failure mileage was unknown.

Timing chain. It had no warning and failed due to poor design and gm in Europe fixed/addressed the issue by installing a plate behind the tensioner a part that isn’t available in the us.

Brake booster went out and lost all braking ability on interstate doing 65 mph in spring of 2022 - had brake booster and exhaust cam replaced and April 20 2025 same break and same effect - no braking ability at interstate speed - extremely dangerous situation

My vehicle’s engine was the component that failed. I was driving home from work. It is a forty-two minute commute. I was five minutes away from home when the vehicle slowed down in speed to a cruise. There were no issues prior after startup. There were no strange sounds, no start up issues, and no lights on the dashboard at all. I noticed that the vehicle had put itself into neutral gear. When I tried to stop the vehicle by hitting the break, the break did not work. I put my foot on the gas pedal and the car did not speed up. I could not change the gears. There was nothing I could do. The vehicle came to a complete stop when it powered off. When the car was put into accessory mode, there was an error message that stated the engine/vehicle was in low power mode. I was not able to start the car’s engine again. It was useless. The only way to move the car anywhere was to have it towed. This failure was scary and dangerous because it occurred in the middle of the night on a main road. Cars are known to drive above the speed limit past midnight in this area. I was glad that there were no cars on the road at the time. I was not aware of this failure occurring for my vehicle no were there any other known recalls. After doing some personal research, I found that GMC and certain Chevy models are having this problem, but no source listed any GMC Terrains as affected vehicles; although the same thing that happened to other people happened to me. I purchased an extended warranty through Fidelity Warranty Services, Inc. (Platinum) when I purchased the vehicle. They were the ones that had done all the necessary inspections for the filed claim once the vehicle was taken to a GMC Service center: Anderson Buick in Cockeysville, MD.

I was 30 seconds away to pull in my driveway. WARNING came up on screen (service) TRANSMISSION UNABLE TO SHIFT. When I turned into my driveway the vehicle stopped suddenly & threw itself into PARK. Vehicle still running but would not go into any gear, drive or reverse. I then pushed the PARK button & I think it said EMERGENCY BRAKE RELEASED. I then proceeded to drive up my driveway with no problem. Haven’t gotten back in vehicle yet as I am afraid to but l made appointment to take it to the dealership to check it out. On 3/24. (Linus Cadillac Buick GMC)Thank god it happened in my driveway as it would’ve caused an accident. ( the vehicle was driven up the Rd. walking distance. Sat there for an hr. Visiting my family. Then was driving home When incident happened. So it wasn’t running hot or anything.

My check engine light comes on intermittently, since March 2024, after having Cabin & Engine air filters replaced. Each time, I’m told it is code P0171. This has happened too many times for my comfort. Usually, it happens around the time my gas gets below 1/2 tank or after I fill up my gas tank. Originally, I was told by the mechanic that it could be one of four things, of which I’ve now had some of things done. InIn Aug. 2024, the check engine light came in. Code was P0171. Mechanic replaced the Brake vacuum pump. Once incident, almost a month later, on 9/24/24, was very scary. While driving on the interstate, I got ready to increase my speed, but heard a pop sound and noticed the speed wouldn’t accelerate. Next, the check engine light came on and the message in the dash popped up saying “engine power reduced” or something similar. I was able to coast from the fast lane over to the slower lane and off the highway into a parking lot. I turned the truck off. When I crunk it back up an hour later, it was shaking and jerking. While slowly driving, on the way to the mechanic shop, it jerked and shook each time I tried to accelerate after stopping at a light or slowing down with traffic. The code again was P0171. According to the mechanic, the intake hose had popped off. On 11/13/24, the check engine light came on. I again took it to have the code scanned and truck looked at. Test results again showed P0171. This time the Mass Air Flow Sensor was suggested. In a year I’ve had the fuel system cleaned twice, brake system flushed, & other routine maintenance such as oil change & brakes. Yet, my check engine light seems to still come on intermittently atleast once monthly. It came on two days ago, 2/18/25, when my gas was around 1/4 tank full. I added a fuel system injector, per mechanic suggestion, and filled my tank up with gas on today, 2/20/25. The check engine light had gone off within about 15 mins of me driving. I’m certain it will be back on soon with the same code.

Brake vacuum pump failed causing engine damage. Camshaft on national back order. Vehicle has been in repair shop for 1.5 months waiting on part. No ETA. There has been recall for similar vehicles with same issue, failure, damage. But not for this VIN. It’s the same failure with same damage. How is this not a recall for this VIN?