2020 GMC Terrain

Check engine light is on took vehicle to dealership 10/13/2023 vacuum booster sensor replaced (37,435 miles) $0 GM Covered cost 12/9/2024 brake vacuum pump replaced (56,456 miles) $0 extended warranty 1/8/2025 vacuum booster sensor replaced (57,087 miles) $252.48 not covered by warranty Check engine light is on 10/11/2025 took to dealership. They were unable to find issue light was off, was told that GM had recommended several things that could be the cause of light coming on still could not find issue. Last thing GM and dealership recommended was to replace the battery. Cost $104.00 Check engine light came on 10/25/2025 while returning home from Tennessee to Michigan, light came on in Louisville, KY. Had it scanned, booster sensor was the cause. Called AAA had them replace battery light went off. (as you know that if you do that it reset the computer not surprised light went off drove rest of the way home to Michigan) Cost of replacement battery $295.00 Check engine light came on again 11/2/2025 my best bet is that it is booster sensor again. NHTSA and GM need to fix this issue. I have not lost breaking ability yet but the horror story that I've read on this site scars me. WHAT ARE IS NHTSA AND GM GOING TO DO WAIT UNTIL SOMEONE IS KILLED BECAUSE OF THIS ISSUE !!!!!!!!

On my 2020 GMC terrain the vacuum pump failed and caused my braking system to go out completely. I had to almost stand up on the brakes to get the car to stop and thankfully I got it come to a stop before smashing into another car. I contacted gmc and while they know this is a ongoing problem and there is a warranty out for this particular problem (150,000 miles or 10 year warranty) I was told it is part/ factory specific and that if it was manufactured in certain facilities or had certain parts that they would cover the cost to fix it but however my vehicle was not covered. This poses a dangerous problem for GMC owners. As soon as the check engine light came on I had absolutely no control over the brakes and it was a miracle it stopped. There was no warning prior to this incident and upon looking up information this seems to be a recurrent problem that GMC needs to address seeing as they say they value their customers.

While driving my 2020 GMC Terrain (VIN: [XXX] ) with approximately 110,501 miles, I experienced a sudden and complete loss of brake assist. After about 2 hours of highway driving, I exited and the brake pedal became extremely hard to press, making it very difficult to stop. No warning lights or messages appeared before the failure. The dealer diagnosed the cause as the brake booster vacuum pipe exploding internally, which immediately eliminated vacuum to the booster. This created a serious safety hazard and nearly caused a crash. I have since had the part replaced, but the fact that this component can fail without warning at highway speed is alarming. GM has issued TSB 21-NA-107 describing this exact failure mode, which indicates it is a known issue. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

As I was driving down the Ohio Turnpike on my way to work on Tuesday, August 5, 2025, my check engine light came on. Almost immediately I got a notification that the car was operating at reduced power. I had no previous issues with the vehicle. As I got off the turnpike my braking system failed. I was able to come to a stop partially in the grass before entering into oncoming traffic. The entire car shut down. I was unable to restart the car. We were also unable to put the car into neutral to push it off of the road the remainder of the way because the wheels were completely locked up at this point. The parking brake was engaged on its own. We also could not get the car into neutral. I had the car towed to a local repair shop, not knowing at all what the issue was. The vacuum pump had failed and broke apart in the engine. This caused my braking system to fail completely also. The vacuum pump on my 2020 GMC terrain has been noted as faulty or defective. However, an official recall has not been issued for my vehicle. Had the pump failed a moment sooner I could have been in a crash trying to exit the turnpike. I took my vehicle to a repair shop and spent $1400 out-of-pocket. The car still does not run correctly now as there are pieces in the engine of my vehicle that were unable to be retrieved.

I was driving on the expressway, attempted to brake and the brakes were stiff and would not go down to stop the vehicle. . Thankfully, I was able to glide over three lanes of traffic and exit the expressway and glide into a parking lot and drove around until the car came to a stop. No lights. No warning. The car had to be towed to my mechanic. This could have been catastrophic. I could have killed someone else or myself. This is the second time that this has happened with this vehicle!!! By the grace of God I am still here writing this complaint. I am traumatized and do not feel safe driving this car. They MUST RECALL this vehicle before somebody gets killed. The issue is with the vacuum pump and I have seen other complaints about the same issue.