2018 GMC Terrain

My vehicle keeps showing “service brake assist” and “service TSC” lights. I was on a hill and the auto-start was engaged, as well as hill assist. When I let off the brake pedal slightly to get the car to come out of auto-start, the car acted like it completely shut off (radio went black and lost power) and the car just started rolling backwards quickly. If there was a vehicle behind me it would’ve %100 caused an accident. My wife and child ride in this car every day and this is the second time I’ve had serious issues with this car. The first time I was driving down the interstate and the brake vaccuum pump went out and I lost all brakes, I had to put all 180lbs of my weight on the brake pedal to get it to stop.

Vehicle brakes went completely hard and vehicle would not stop. There was no warning signs, no lights on the dash and vehicle was driving on highway normally. Upon taking a highway exit, I could not stop the vehicle, completely unexpectedly. Upon further research it is a very common problem that needs to be addressed. My 3 kids and wife were in the vehicle when it happened, and this is actually the second time it has happened. The first time it happened we could not stop the vehicle at all to turn onto the road I live on, could barely push the brake pedal and coast to a stop. The repair last time it happened was the camshaft driven brake booster vacuum pump, and it has failed again after 20,000 miles. This is a serious manufacturer defect that has almost killed my family twice now.

While driving down the road at approximately 55 mph, came up to an intersection, 4 Lane I was in the right lane to go straight, there was a right turn lane next to me. I applied the brakes, pedal was really stiff and very slow to respond, I was able to edge over into the turn lane cutting people off and just barely missing the vehicles in front of me. It took 5 car lengths to stop my vehicle. When I finally was able to get the vehicle fully stopped I was almost in the paths of the crossing traffic.. when the light turned green I was able to slowly cross the intersection looking for a safe place to pull over. Immediately crossing the intersection the Service Brake Assist notification appeared, about another half mile the vehicle informed me of loss of power and that it was reducing engine power (limp mode). I was able to find a gas station parking lot to put it. When I opened the hood I noticed quite a bit of engine oil located under where the brake assist pump was located. I had lost about 1.5 quarts of oil. I refilled that. The next day I returned with a tow dolly. The vehicle was started just long enough to load and unload it at home. We pulled the vacuum pump where upon inspection it was noticed that the part has exploded and so far we are still missing some pieces that may be inside the engine. This is a known and documented problem of this part and should have a safety recall issued. . I still owe over twenty eight thousand on this vehicle and it has only 109,000 miles on it. I hope we can find all the pieces and that the engine wasn't fately harmed. GMC needs to make this right, a lot of people could have been harmed.

The contact owns a 2018 GMC Terrain. The contact stated that while driving at approximately 35 MPH going over a hill, the brake pedal was depressed but was firm and failed to depress as needed. The engine power reduced message was displayed and flashed on and then off. The brake assist warning light was illuminated. The service transmission message was displayed. The contact continued to depress the brake pedal until the vehicle responded as needed. The driver was able to pull into a parking lot, and the vehicle rolled to a stop. While driving, the engine misfired. Additionally, the vehicle failed to fully shutoff. The vehicle was towed to the local dealer, where it was diagnosed that the brakes had locked up and that the vacuum pump needed to be replaced. The contact was also informed that the cam shaft had fractured inside the engine. Additionally, the fuel injector, fuel line, and fuel pump needed to be replaced. The vehicle was not repaired. The contact related the failure to NHTSA Campaign Number: 19V645000 (Service Brakes, Hydraulic) and 23V013000 (Fuel System, Gasoline). The manufacturer was contacted, and the contact was informed that the VIN was under recall. The failure mileage was approximately 30,000.

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.

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