GMC Complaints

Radiator Hose began to leak coolant. Faulty radiator hose. This could have caused engine failure and potentially caused an accident or may have put others at risk for hazards. No warning other strange sound. Inspected by authorized dealers service center.

Hi, was driving Vehicle GMC 1500 Denali, vehicle Lost power, all Lites lite up on Dashboard, Vehicle Just lost power and i swerved off Road and sideswiped a Plant Holder on side of Road, damaging side passenger Rear door. I bought the truck to GMC Rvc and they said vehicle Blew Cam shaft and Lifters. I explained to them I'm very concerned for others safety in these Vehicles with the 6.2 Engine. Someone is going to get Killed or even a family. I did look up this vehicle its not listed in Recall, but this vehicle has same engine as ones in Recall. Rvc Gmc issued me a bill for repairs for the amount of $8185.20 and they stated they took 3k off invoice. I did Pay total Invoice....I'm just asking you to please look into this as this is defiantly an issue and this year should be listed on Recall as well.. Thanku for at least looking at this. My cell is [XXX] if you need to reach us...Thx.... INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2014 GMC Sierra 1500. The contact stated that while driving 30-40 MPH, the vehicle lost motive power, and RPM became raised. There was no warning light illuminated. The vehicle was taken to an independent mechanic, and was diagnosed with lower and upper fuel pump failure. The contact was informed that the lower and upper fuel pumps needed to be replaced. The independent mechanic made the contact aware of TSB Number: 13370A (Fuel Pump). The vehicle was not repaired. The manufacturer was notified of the failure and the TSB; however, the VIN was not included. The manufacturer opened a case. The approximate failure mileage was 105,000.

Tailgate opens randomly on numerous occasions. Sometimes it won't open after pressing the button.

On highway taking an exit. The brake pedal sank and did not engage at normal pressure, I had to push the brake all the way down for it to engage. Concurrently the steering wheel locked up where I could not turn the wheel at all. I drove straight through the exit ramp to the entrance ramp, luckily no one was entering the highway at the same time. I very well could have hurt some one else or myself. The steering wheel finally engaged where I had full power steering again and I was able to remove my truck off the highway and cautiously drove to a parking lot to get it towed. I have not tried to drive sense incident as it is at the dealer for service. The GMC Dealer has not inspected the vehicle yet, they are backed up with other services. There were no warning lamps at the time nor before the incident. Symptons see bellow. I have had issues with the brakes and it has been to the dealer 4 times including this incident, Service issue #1 at 21,501 miles -Breaks were pulsating, squealing and rough and it was shaking the steering column - The smell of burning breaks was present after drives -Solution they sanded down the hot spots on both rotors and pads for the front brakes Temporarily fixed the breaking and steering column shaking ( it did not solve the burning break smell problem. Service issue #2 at 28,142 miles Breaks were pulsating, squeaking, and steering column shaking - The smell of burning breaks was still present after drives. solution new front brake pads and rotors. Service issue #3 at 39,893 miles Rear brakes locked up while taking a turn on to a street Breaks were pulsating Squeaking and steering column shaking Smell of burning breaks is still present after drives solution machine front brake rotors. could not reproduce brake locking issue Final issue as mentioned above #4 @43,426 miles I cant help but think the constant break issues were warning signs.

The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving approximately 45 MPH on bumpy terrain, the driver’s and passenger’s side curtain air bags deployed unexpectedly. No warning light was illuminated, and there was no impact to the vehicle to cause the air bags to deploy. The vehicle was taken to a local independent mechanic, where it remained for further investigation. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 80,000.

The contact owns a 2024 GMC Sierra 3500HD. The contact stated that while driving at various speeds, there would be a diesel odor coming into the cabin of the vehicle. The failure had become more persistent, causing black smoke to enter the cabin of the vehicle. The failure caused the contact and other vehicle passengers to have headaches, nausea, and dizziness. While driving approximately 65 MPH, the contact began speaking to their daughter, sitting in the front passenger seat, and noticed her not responding. When looking over, the contact noticed her daughter's head was lowered. The contact immediately pulled over to the side of the road, where she pulled her daughter out of the vehicle and called an ambulance. A fire truck was also dispatched in order to drive the vehicle to the fire department, where they tested the vehicle; however, they were unable to duplicate the failure. The contact's daughter was taken to the hospital, where it was determined that she had suffered from carbon dioxide poisoning. The vehicle was taken to the dealer, who diagnosed that the Diesel Particulate Filter (DPF) was clogged, and that the Exhaust Manifold and Turbo Inlet were both fractured, causing a blockage in the Engine Bank. It was determined that all the avenues through which air and carbon should have been exiting the vehicle had failed and were causing everything to come into the cabin of the vehicle instead. The vehicle was scheduled for repair; however, only the exhaust manifold could be repaired, while the other parts, such as the DPF and hose, were on national backorder and awaiting retrieval. The manufacturer was informed of the failure, and a case was opened. The contact stated the manufacturer had been avoiding acknowledging that black smoke had been entering the vehicle's cabin and had yet to resolve that issue. The failure mileage was approximately 20,000.

I bought my car in July of 2025 and since then my car keeps derating and reducing engine power while driving down the road at 70 miles an hour. It cuts out and decreases power. I took my car to the shop twice to have them tell it needed an update. I drove away and then the car does it again. Since December my car has down this decreased power, derated notice more than 30 times!! It is a safety risk for me and my family because you never know when it will happen on the interstate and when you will lose power. I have almost been rearended 3 times due to this issue and no one can seem to fix the issue.

1st Failure. August 28, 2025. Vehicle stalled out while driving with NO warning. Check engine light stayed on. Could not drive. Car towed to dealership. Scanned codes found: p0089, p00c6 and p228c. Cause: Internal failure. Bulletin pertaining to this issue performed. Program of ecm per bulletin. 2nd Failure. February 19, 2026 Vehicle stalled out a 2nd time while driving with NO warning. Check engine light stayed on. Could not drive. Towed in a 2nd time. Scanned codes found: p0089, p00c6, p228c and p2c1f. Cause: internal Fault. Fuel pump power control module replacement. Fuel pump replacement. 3rd Failure. March 4th, 2026. Vehicle stalled out a 3rd time while driving with NO warning. Check engine light stayed on. Could not drive. Towed in again to dealership. Currently sitting at dealership waiting on repairs a 3rd time for the same thing. Wife is 76 years old and is terrified to drive this car. What if this stalls out on the freeway in traffic. Car is unsafe to drive.

The backup camera in our 2019 GMC Terrain stopped working one day - has blue screen and says Service Rear Vision System - so we’ve been driving a year with no backup camera. The dealership wants almost $1000 to fix this issue. And this issue seems to be very common in 2018-2020 Terrains. We bought the vehicle in December 2023