2018 GMC Terrain driver assistance problems

Filed Jul 17, 2026 · Brakes, Driver assistance · PA

The vehicle has had regular maintenance, oil change, and inspection including the brakes. My boyfriend is visiting me in [XXX] from the [XXX]. OnXXX while driving the vehicle the engine started. Making a ticking noise especially during idle and when accelerating in idle. About 15 minutes after the ticking stopped and all of a sudden there's a complete loss of breaks they locked up and the driver was unable to efficiently stop while going down a hill Road. Driver had to use the emergency brake to make the other brakes release and then the brakes from there would not work even though you could stomp on them stand on top of them there was no breaking power anymore. Vehicle was brought into a GMC dealership on the following Monday where they confirmed the issue was a failed vacuum pump connected to the engine and camshaft which is a known safety issue to GMC as part of an ongoing open case they had specialty coverage and bulletins regarding the Tahoe and Sierra but neglected to include the terrain on this issue. Cold the GMC manufacturer in both [XXX] and [XXX] to try and get cost assistance and specialty coverage as the vehicle as well under the mileage requirements but have been giving the push around and zero assistance. The risk to the drivers and passengers lives was significant as we were on the highway for1.5 hrand thankfully the brake lost didn't happen in full during that time. The repairs were completed and paid for in full by the client which should have been covered by the dealership and we are looking for cost recuperation and are now being ignored. Receipts are here to substantiate the claim. The ABS light is no longer on there was no warnings on the vehicle showing any issues or any codes as OnStar was called and diagnostics were received and the diagnostics came back clear prior to this happening, and following the break failure. Lack of codes and warnings is life-threatening and serious. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 22, 2025 · Driver assistance · KY

It starts to “warn” you by the seat doing whatever it does and the dash lights up collision flashing and slams on the brakes when nothing is even around

Filed Aug 6, 2024 · Driver assistance, Visibility · VA

The headliner fabric detached somehow from the panoramic track causing the fabric to hang down obstructing the rear and back window view causing a safety hazard. The automatic forward collision alert will come on for no reason since this has happened. The problem has not been reported to insurance or the manufacturer yet but GM is my next call. This is a safety hazard due to the obstruction of visibility to safely make turns or change lanes. This happened August 5th while driving with the windows up. It just dropped down still attached to the front of the track and the rear.

Filed Jul 18, 2024 · Driver assistance · IL · crash

I was in a car accident

Filed Sep 18, 2023 · Driver assistance, Transmission · TN

Car is losing go power when accelerating on to interstate. It’s like the transmission loses power, the d illuminates, and then it kicks in to drive. It puts us at risk for an accident and I had a semi almost hit me because of this. This has been reproduced at the mechanic shop as well. No warnings before this happens

Filed Sep 6, 2023 · Brakes, Driver assistance · IL

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.

Filed Sep 12, 2022 · Brakes, Driver assistance · WV

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.

Filed Jun 14, 2022 · Driver assistance, Electrical · AL

Radio, hands free calling, and light on mirror shorting out. None of them work. It’s like it has a short in the wiring.

Filed Jun 1, 2021 · Brakes, Driver assistance · MI

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.

Filed Apr 12, 2019 · Driver assistance, Engine · 25,000 miles · PA

While the vehicle is in drive it loses propulsion without notice. The vehicle stays in drive. The vehicles RPM increase as your foot is on the accelerator but the vehicle doesn't continue to move. The only way to regain propulsion is to completely shut the vehicle off and then start up again.