2018 GMC TERRAIN Complaints

When driving the car at low speeds, or right after having been stopped for a few moments. Upon, acceleration, the car will sometimes go into a limp mode. On the DIC, will be displayed a warning about how the car will have the speed reduced after 175 miles and to check the emissions system. The speed has already been reduced at that point. Also displayed maybe a warning about how the power has been reduced. USUALLY, if I turn off the car and wait about a minute, I can restart the car and drive at a normal highway speed again. But not always. The warning on the DIC, will usually turn off if the car does return to normal speeds after about 5 - 10 miles. However, the check engine light may still stay on for several days. This problem can be a daily occurrence. I've had the car in the shop several times, and they have been unable to fix the problem. The car can be unpredictably unsafe, when speed is instantly reduced to 30 mph!

The contact owns a 2018 GMC Terrain. The contact stated while driving at various speeds, the brakes became inoperable. While the vehicle was in park(P), the gear shifter inadvertently shifted into an unintended gear. The brake assist warning light was flashing. The vehicle was taken to the local dealer where it was diagnosed that the vacuum pump and brake booster needed to be replaced. The vehicle was repaired four times but the failure persisted. The manufacturer was contacted and informed the contact to take the vehicle to a local dealer if the failure recurred. There was no additional assistance provided. The approximate failure mileage was 131,000.

Vehicle stuck in emergency assist mood. Without warning I couldn't slow down/stop without putting alot of my weight on the brake breaks were so hard to press down.

When trying to brake, brake pedal became extremely hard to push and Repair brake assist notification and check engine light came on

Vacuum pump went out brakes hard to push and I know gmc had a recall for this issue on other vehicles as well previously.

Brake has to be pushed all the way down HARD to stop, brake assist warning comes up. I’ve had the car for less than 2 years and it’s way too new for anything to go out. Undriveable unless it’s fixed.

The Safety Restraint System warning keeps coming on and off as well as the air bag light. It happened months ago so I took it in and got it looked at and scanned. All the seatbelts were checked and the scan came back with nothing. Then it stopped for a couple months and now it has started again. Ive had 14 surgeries in the last little less than 4 years and I'm about to go into my 3rd back surgery since November. I cannot get into an accident and not have airbags as I've also had brain surgery 3 winters ago as well. I am disabled and do not have a ton of money either for fixes that aren't necessary but this safety issue is crucial to me. I see that many 2018s have been recalled for the exact same issue that I'm having however mine doesn't come up with that but it is happening to me so that should be included. I also need some direction if not as to why this is happening because I cannot afford to have a dealership, no less, replace every tiny little thing looking for the culprit at $150 an hour when I live on $1,200 a month and most goes to medical. Please advise on what to to or where to start. Thank you.

While getting off the interstate, the brakes failed with no prior warning, or issues. The brake pedal became extremely difficult to depress and stopping distance was greatly increased. Could not come to a complete stop without using the emergency brake. We drove home (about 2 miles from the interstate exit) and about a half mile after the brake failure, a "service brake assist" light illuminated. Vehicle was towed to dealership the next morning. The problem was the vacuum pump exploded and caused vacuum to the brake booster to be lost, making the pedal difficult to push. Luckily this happened at 11pm and there was nobody in front of us, there definitely would have been a collision.

At ignition, vehicle tire pressure monitoring system indicated low tire pressure in rear right wheel of 9psi; right front tire indicated 38psi and left front and rear indicated 38psi. Driver verified pressure as good at 38psi in rear right tire with hand held gauge. While operating the vehicle on the interstate, vehicle driver experience a flat tire in the right front passenger tire. Tire Pressure monitoring system indicated 41psi in right front tire (even while flat), and indicated right rear tire at 0psi even though it was visually inflated.

I have a 2018 GMC TERRAIN which I bought brand new from General Motors. In May 2022, the vehicle started jerking/hoping and trying to stall when the speed gets to 55 miles per hour or higher. I have taken it to the dealership on three different occasions for repair and I still have this issue. General Motors engineers were involved in every step of the repairs. They just do not know what is going on with the car or fix it and they are too stubborn. The dealership told me today that they cannot do anything else to the car. They also said they had a code from the engine last week and General Motors said they do not know what that code means. They are forcing me to accept/drive the car in this unsafe condition. I have contacted them multiple times and they do not care.