Three problems related to automatic emergency braking have been reported for the 2018 GMC Terrain. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2018 GMC Terrain based on all problems reported for the 2018 Terrain.
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.
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.
The "service brake assist" issue in other 2018 GMC suvs is happening in the 2018 GMC Terrain, but it is not part of the recall. Our brakes became extremely difficult to press right as we were turning onto the on ramp of an expressway. Thankfully we were Smart enough to pull over and not get on the highway. Had we done so, I may not have been here to type this complaint. The brakes be come extremely difficult to press and that message shows. Dealership is going to charge me $400 to replace a vacuum pump - they were not interested in the information I have around this issue in other GMC suvs since it isn't a formal recall on the Terrain. I could have died yesterday due to this braking issue. I've owned this car for 3 months.