2018 GMC TERRAIN Complaints

On 9/3/23 I was travelling down interstate 94 in Illinois when all of a sudden my check engine light came on. Not knowing what the issue was, but knowing that the car still seemed to be OK and I was only a few miles from home I decided to drive home and figure out the issue from there. At this point I had no idea that the brakes had completely locked up. Once I realized what was happening I did my best to slow the vehicle down by decelerating, frantically pumping on the locked up brakes, and then finally slowing enough to take an exit and roll in to a gas station. Frankly, it was the most terrifying moment of my life travelling 70 MPH without the ability to stop. Upon inspection, the independent service tech informed us that the vacuum pump had exploded (yes, exploded) and that he had never seen anything like it, especially in a car with less than 70,000 miles. What component or system failed or malfunctioned, and is it available for inspection upon request? The vacuum pump failed and unfortunately it completely exploded so there were only a few pieces left inside of the engine. How was your safety or the safety of others put at risk? My brakes locked up completely on the interstate, with my family in the car, and I was unable to stop. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. The independent service center where I currently have the vehicle has confirmed, and spoken with GM. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? No, GMC refuses to do anything about it even though there is a prior recall for the same part on other GMC vehicles during the same time frame. I'm told it's the exact same part. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? Yes, roughly 1 minute prior to the breaks locking up the "check engine" light came on.

The contact owns a 2018 GMC Terrain. The contact stated while driving approximately 30 MPH, the vehicle decelerated and failed to accelerate over 25 MPH while the accelerator pedal was depressed. The contact stated that a message was displayed on the instrument panel to “Continuously Drive Vehicle Above 30 MPH”. The contact stated that after the vehicle decelerated into engine power mode, the check engine warning light illuminated. The vehicle was taken to the dealer where it was diagnosed that the Diesel Particulate Filter (DPF) failed and needed to be replaced. Additionally, the contact stated that the vehicle was taken to the dealer twice where it was diagnosed that the Diesel Particulate Filter (DPF) needed to be unclogged. The vehicle was repaired; however, the failure recurred. The vehicle was not repaired. The manufacturer was notified of the failure and the contact was informed to contact the warranty company, but no further assistance was provided. The failure mileage was approximately 110,696.

Driving on highway and all of a sudden I could not break - the car breaks failed to operate - had to slowdown by it self and pull to a McDonalds, I had the loss of effective braking with no warning whatsoever. We found out that the Break Booster Pump was destroyed without any warning from the electronics of the SUV.

Last year this time brakes went out at 50 mph power brake module imploded from inside out. The part was on national back order. Second incident car stopped immediately while traveling 40 mph no warnings or anything both incidents could of been horrible . Not sure on second incident the issue yet car is in shop. Both incidents are safety concerns for myself and others. Driving at average speeds and something malfunctioning is a great concern of mine. I contacted GMC no one to talk too just chat and the person on the other side told me it was no concern of theirs all was dumbfounded by the conversation but until I said I was putting on social media and bringing to everyone attention her entire tune changed in regards to part and service. So I researched locally and luckily I found the part they had one left and I was told by dealer that it is an issue on these vehicles. Both safety incidents have been within a year of each other 2022 and 2023

The vacuum pump started leaking and the car was parked immediately. When The pump was pulled out to be replaced, the reason for the leak was identified. The vacuum pump had busted into small pieces which are now in the engine.

Transmission failed. Unable to purchase a replacement as there are no available transmissions for this year terrian.

My husband and son were involved in an almost fatal accident on 07/08/23 in our 2018 Terrain. My husband described that the vehicle spontaneously veered to the right uncontrollably, he was unable to steer to correct the vehicle, unable to brake, they went airborne, hit several poles and a transformer, rolled and flipped several times. All the airbags deployed.After the accident, I found a recall notice from back in 2017, I believe, regarding the drive train. My husband was extricated from the vehicle. My son wasble to cut the seatbelt and crawl out the window. From what my husband explained (he was the driver), this sounds like what they experienced during the collision. I never received a recall letter from GM as this is something I would of taken care of and have got repaired. Please see the photos and the recall I found. Please let me know if there is anyone else I need to contact regarsing this collision.My car was almost paid off. My husband and son could of lost their life. Please advise. Thank you!

Catalytic converter went out at 101,650 miles and the dealer has no replacement part. This is the diesel engine, almost every other year was recalled and they extended the warranty to 100,000 miles. And they stopped making this engine. Seems like they should at the least have a replacement part for a car 5 1/2 years old. They also said the 2017 were recalled, this vehicle was built Jan 2018. The vehicle currently will only go 5 MPH so it cant be driven. There was no warning of the failure.

The contact owns a 2018 GMC Terrain. The contact stated while driving 45 MPH, the check engine warning light illuminated. The contact stated while making a left turn the brake pedal was depressed but failed to stop the vehicle. The contact was able to continue driving without proper braking response to her residence. The contact stated she used the parking brake to fully stop the vehicle. The contact's husband took the vehicle to the local dealer, where it was diagnosed with needing an unknown pipe and vacuum pump to be replaced. The vehicle was not repaired. The manufacturer had not been informed of the failure. The failure mileage was approximately 79,000.

In mid traffic my 2018 GMC terrain just stopped with no warning, no check engine lights, no smoke from the vehicle, nothing. I was in Charlotte traffic, driving, with my family in the vehicle, the car stopped right in the middle of driving, and I had to quickly and sharply turn the wheel to got into a median to avoid hitting the car in front of me and avoid being rear-ended. The dealership informed me that the vacuum pump in the engine cracked (broke) causing another part in the engine to malfunction. There were no, none, warning lamps, messages, or other symptoms prior to this incident that would of indicated a problem so that I can proactively service the vehicle and keep my family safe.