There are 9 owner-reported speed control & cruise complaints for the 2020 GMC Terrainin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
Random problems accelerating. Like I can be pulling out of my parking spot in revese then switch it to drive an try to move and it won’t move at all or very slowly then out of nowhere it accelerates fast
While on highway service brake system warning light came on,brake became hard to apply almost causing an accident. Vehicle had to be towed to a repair shop(dealer).after paying over $1600 the problem was not resolved and found there are numerous complaints about issues with the terrain and no recall issued.are they waiting til someone dies before a recall?
My vehicle begin stalling when accelerating (mostly after stopping) June 2023. My vehicle has almost cause me to have two accidents because it intermittently stalls when I try to cross an intersection. This is my fourth time taking my vehicle to the GMC dealership, and they tell me they can't find anything wrong if there is not a code. I have reached out to Corp, and I'm waiting to see if they can help get to the bottom of my problem. My car has been sitting at the dealership since June 30th 2023....I call the dealership periodically, and they never reach out to let me know what's going on. I am afraid to drive my vehicle at this time because next time another car may not be able stop and give me time to get across the road. I'm filing this complaint because I seriously think someone is gonna get killed.. Thank you
On 4/10/2023, I took my vehicle to a local GMC dealership because it was stalling and didn't have any power. Upon accelerating the vehicle it would stall and take off at a high speed. The dealership has had my vehicle periodically from April 2023 and it presently sets at the dealership because they ain't getting a code, But after the dealership drove the truck for over 200 miles, they were finally able to duplicate the stalling yet are not able to diagnose the problem!! This vehicle is very dangerous to be on the road and I have almost gotten hit twice and I'm not driving the vehicle anymore at this time. I have previously reached out to you all and I would be most thankful if you could get in touch with me. Thank you
As I was driving on the highway in New York on Route 17 south near exit 111, I tried to accelerate but when I did the car went slower and the check engine light and traction control lights came on. I was right in front of a huge truck and thank God I was in the right lane that I was able to quickly get on the shoulder and turn the car off. I was able to make it to where I was going, but it was very nerve wracking. I took the car to the dealer service center and was told that it was probably a fuse issue. It turns out my entire engine has to be rebuilt. I have approximately 25,000 on my car, how could it require an entire engine rebuild? The dealer has gotten me two rentals cars that only last 5 days at a time each time and now I’m driving a dealer loaner. It’s been 3 weeks and still nothing. I’m still making payments on my car.
Not long after I bought my 2020 GMC Terrain my adaptive cruise started disengaging. There are never any warning lights, except the noise and vibration of the seat before it shuts off then tells you it's disengaging. I didn't think anything of it until it's became a regular occurrence in the last month or two. I tell my dealership about it and they drive it but it never disengages on them, so they say nothing is wrong with my vehicle. I have a picture of the "adaptive cruise disengaging" and video of where I can't reset it until after about 15 or so minutes or letting my car set for a while or turning off the engine then it works again. I also have noticed that my auto start/stop hasn't been turning on & off anymore.
PURCHASED NEW 2020 GMC TERRAIN W/7MILES. LEFT DEALERSHIP ON MY WAY HOME, AND WITHIN 20 MILES, RECEIVED A MESSAGE ON DASH-> SERVICE - ESC - DISMISS. CHECK ENGINE LIGHT FLASHED SEVERAL TIMES, AND THE SUV SLOWED DOWN AT LEAST 10 MILES FROM 65MILES PER HOUR. AFTER ENGINE LIGHT STOPPED BLINKING, I CONTINUES HOME AROUND 30 MILES MORE WITH NO MORE PROBLEMS. CALLED MY SALES PERSON THE NEXT DAY, AND HE DID NOT KNOW WHAT ESC WAS. (ELECTRONIC STABILITY CONTROL) HE CALLED ME BACK AND INDICTED THE VEHICLE MAY NEED A SOFTWARE UPDATE. I TOLD MY WIFE, WHY WOULD A DEALERSHIP NOT CHECK ON VEHICLE SOFTWARE UPDATES BEFORE RELEASING VEHICLES TO THE NEW OWNERS, PRIOR TO LEAVING THE DEALERSHIP. THIS IS CALLED, "BEING PROACTIVE." WE WERE ON THE HIGHWAY LEAVING THE DEALERSHIP AFTER PURCHASING THIS NEW SUV.
EVERY WEEK IT'S SOMETHING DIFFERENT. IN MOTION... NO CRUZE CONTROL. NO AUDIO. DON'T DRIVE OVER 50MPH BRAKE PROBLEM. PARKING BRAKE ENGAGES RANDOMLY AND WITHOUT USER ENGAGEMENT. NO AWD. NO STABILITY TRACTION. THIS HAPPENS SO FREQUENTLY THE DASH INDICATORS HAVE BEEN REDUCED TO 'IDIOT LIGHTS'. AT WHAT POINT DO I BECOME CONCERNED? THINGS APPEAR TO RESOLVE WHEN THE ENGINE IS TURNED OFF AND BACK ON, SOMETIMES....I COMPARE IT TO OTHER GLITCHY TECHNOLOGY. HOWEVER I POTENTIALLY COULD BE AT AN 80MPH CRAZING SPEED WHEN I DECIDE TO IGNORE THE IDIOT LIGHTS...WHAT HAPPENS WHEN A REAL PROBLEM PRESENTS AND I IGNORE THE DASH INDICATORS DO TO FREQUENT GLITCHES? I'M SO DISAPPOINTED. MY 2 PREVIOUS TERRAINS WERE 10 TIMES THE VEHICLE THE 2020 MODEL YEAR.
WHEN CRUISE CONTROL IS ENGAGED AT 71MPH, HOLDING +RES BUTTON TO INCREASE SPEED AND RELEASING IT AT 77MPH SETS CRUISE SPEED TOO HIGH. CAR CONTINUES TO ACCELERATE. CRUISE GETS SET AT 100MPH AND ACCELERATES MORE THEN DESIRED. SEE LINK WITH VIDEO OF EVENT HTTPS://PHOTOS.APP.GOO.GL/O7ZGEQWCSU7KYCV58 SEE ATTACHED PICTURE OF OWNERS MANUAL
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 26, 2026