2026 GMC Terrain Driver assistance Problems

On the evening ofXXX, at approximately 6:00 PM, I was driving this Avis rental vehicle on a highway in [XXX] at normal highway speed, below the posted limit, with my foot on the accelerator. The forward collision warning and automatic emergency braking system activated and applied the brakes hard. There was no vehicle, pedestrian, obstacle, or hazard ahead of me, and no vehicle behind me or beside me. The roadway was clear and dry. The sun was low in the sky, and the vehicle was crossing a metal expansion joint on an overpass at the moment of activation. I believe the low sun angle, the expansion joint, or both caused a false object detection by the forward-facing camera or radar. The service brakes themselves functioned correctly. The failure is in the forward sensing and decision logic, which commanded a braking event with no object present. The deceleration was severe and unexpected. I sustained sharp pain in my neck and shoulder. Had any vehicle been following me, this would have caused a rear-end collision at highway speed. There were no warning lamps, messages, or other symptoms before the event, and none afterward. I had driven the vehicle for seven days with no prior indication of a fault. I exited the highway immediately and drove back to the rental location on local streets at low speed because I no longer trusted the vehicle. I returned it the following morning when the Avis office opened, more than a day early, and reported the defect. Being a rental vehicle it was not available to me for inspection. The rental company has advised that it was taken out of fleet for inspection after my return, that there are no open recalls on it, and that it will not release internal service records to me. I do not know the outcome of that inspection. To my knowledge the fault has not been reproduced or confirmed by a dealer, independent service center, or manufacturer representative. No police report was filed because no collision occurred. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S

NHTSA ID

11766350

Incident

Aug 29, 2026

a failing telematics module on your 2026 GMC Terrain is causing network corruption, leading to an erratic speedometer and loss of driver assistance systems while driving.

NHTSA ID

11765984

Incident

Sep 18, 2026

When starting to accelerate from a red light. The car in front of us was accelerating faster. Yet our car initiated an emergency braking action at around 15 MPH. It was very jarring and I still have a headache more yhan 1 hour after the incident.

NHTSA ID

11760736

Incident

Aug 30, 2026

Subject: Urgent: Unresolved Ongoing Vehicle Issues - Request for Contact ​To Whom It May Concern, ​I am writing to express my strong frustration regarding ongoing and unresolved issues with my vehicle. Ever since I purchased it, I have been plagued by constant alerts regarding various vehicle failures. ​My vehicle has already been reset and updated twice to address these issues. I just picked it up after it was supposedly fixed at the dealership this past Thursday. However, today, Sunday, [XXX], the exact same warning alerts have started popping up once again. ​This situation is unacceptable, and I need someone to reach out to us immediately to discuss a permanent resolution. Please contact us at either of the following numbers: ​Primary Phone: [XXX] ​Secondary Phone: [XXX] ​I expect a prompt reply to arrange the next steps. ​ INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11758926

Incident

Jul 10, 2026

The contact owns a 2026 GMC Terrain. The contact stated that after a software update was performed, while driving at an undisclosed speed, the message "Departure Lane Limited due to the Trailer" was displayed. The failure affected the blind spot warning system. The warning light failed to display while approaching a vehicle on the blindside and erroneously operated while there were no vehicles on the side of the vehicle. Additionally, the "Rear Cross Traffic Warning" light was affected by the failure. The vehicle experienced hard braking while there was no other vehicle nearby. The dealer was contacted and diagnosed the vehicle with sensor failure caused by an impact to the sensor. The vehicle was not repaired. The manufacturer was made aware of the failure and referred the contact to the NHTSA Hotline to report the failure. The failure mileage was approximately 11,350.

NHTSA ID

11755239

Incident

Jun 25, 2026

Mileage

11,350 mi

Two issues here. First is that the car will give a danger warning when nothing is there. Sometimes goes as far as slamming on my breaks. Both in drive and reverse. Second is the lane keep assist. It’s like it is working backwards. I turned this all off because it would jerk me out of the lane and into the other lane or off to the sides of the road.

NHTSA ID

11737214

Incident

Dec 1, 2025

The system that failed was the brakes, The car is availble for inspection. My saftey and others was put at risk due to not having brakes to stop. The problem has been confirmed by a dealer as a master brake cylinder failer The vehicle has been inspected by the dealer. There were warning lamps, message and other symptoms of the problem prior to the failure. They first appearead on December 4 2025

NHTSA ID

11710663

Incident

Dec 4, 2025

I was driving (roughly about 30 MPH) when my automatic braking kicked on and caused my tires to squeal to a halt. There were no other cars around me (thankfully) - otherwise I would have been rear-ended. Right before it stopped, it flashed the warning lights for a quick second. I wanted to report this issue in case others are experiencing the same problem and to hopefully help prevent it from happening to someone else. Very scary and could cause a serious accident. I turned off all of my automatic brake settings after the incident, as I believe it is faulty and don't want to risk it happening again.

NHTSA ID

11707983

Incident

Dec 29, 2025