GMC Complaints

Vehicle would not run due to a failed fuel pump control module. With a non-running engine, the transmission could NOT be placed into Neutral to be able to movie vehicle out of the road. Needed tow truck to move vehicle. This condition placed many people at risk as the vehicle could not be moved out of the way until a tow truck arrived.

My 2019 GMC SLT seems to be having sensor problems. I keep getting a message that my driver assist is reduced and my A/C only blows out hot air. It’s done this to me randomly id say about 4-5 times. It will go off as I’m driving and than my temp gauge goes to zero. I did research and alot of other users have the same issue and say thermostat or thermostat sensor. If I disconnect my negative on battery and wait a few minutes it will work again.

My SUV pulls hard to the right when braking at speeds above 50 mph and much more on the interstates at 65 mph and above. I first experienced this after three weeks of ownership on a drive up I-95 on a trip to NC. It has happened numerous times while traveling on the interstates and has almost caused loss of control when having to brake hard when cut off by another driver or traffic suddenly coming to a stop. The vehicle has been to the service department numerous times....at first they suspected a braking issue and have had both calipers replaced, all brake lines replaced, lower control arms replaced and the right side strut replaced. None of these repairs have solved the problem. The factory service rep who took over the situation tested 3 other GMC 2025 Terrain suvs and all had the same problem. He reported the issue on a safety report to GM in Michigan and the response from GM was that it is a normal condition for the Terrain models. I have never owned, driven, or ridden in another vehicle in over 50 years of driving which performed like this, this is not a normal condition in my opinion.

The contact owns a 2025 GMC Sierra 3500. The contact stated that the transmission was shifting hard and was jerking while shifting gear. Additionally, the vehicle failed to accelerate above 50 MPH. The messages “Reduced Acceleration” and “DEF Low” were displayed. While refueling the vehicle, the fuel gauge failed to correctly display the level of fuel inside the fuel tank until the vehicle had been driven for approximately 20 minutes. The vehicle was taken to the dealer to be diagnosed, and the contact was informed that the transmission needed to be updated. The system was recalibrated; however, the failure persisted. The vehicle was taken to another dealer, George Kell Motors (3808 Van Dyke Rd, Newport, AR 72112); and the system was recalibrated. However, the failures persisted. While driving approximately 60 MPH, the transmission was shifting hard, and the vehicle took over 2 hours to drive 19-miles. The engine temperature gauge fluctuated between 185 and 188 degrees. The vehicle was pulled over to the side of the road to cool down before continuing to drive, while not exceeding 40 MPH. The vehicle was taken to a third dealer, Fremont Chevrolet GMC Riverton (1401 N Federal Blvd, Riverton, WY 82501); who determined that the bell body needed to be replaced. The vehicle was scheduled to be repaired, but parts were on back order. The contact became aware that there was a recall related to failure; NHTSA Campaign Number: 26V129000 (Fuel System, Gasoline); however, the VIN was not included. The manufacturer was not made aware of the failure. The failure mileage was approximately 40,000.

What component or system failed or malfunctioned, and is it available for inspection upon request? The vehicle experienced a malfunction associated with a failed Over-The-Air (OTA) software update affecting electronic control modules. The (ECM), (BCM), and related electronic systems appeared to lose stability during operation. The vehicle attempted to reboot while being driven and displayed multiple system warnings. The vehicle is currently at the dealership and is available for inspection upon request. How was your safety or the safety of others put at risk?While driving, the vehicle began malfunctioning and attempting system reboots. The dashboard flickered, warning lights, and the vehicle exhibited unstable behavior. During a prior event, the vehicle experienced unintended acceleration and abrupt deceleration. This created a risk of loss of vehicle control, particularly in traffic. I have small children in this vehicle, and the unpredictable electronic behavior while in motion posed a significant safety concern. Has the problem been reproduced or confirmed by a dealer or independent service center? The dealership confirmed that a previous event was caused by a failed OTA software update. The vehicle has since malfunctioned again while driving and has been taken back to the dealership for further inspection. The dealership has acknowledged module instability and opened a TAK case with the manufacturer. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? The vehicle has been inspected by GMC1 dealership. A case has been opened with GM Customer Care. No police or insurance reports. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? 9 days prior to the first major malfunction, the check engine light illuminate. On April 1, the check engine light re-appeared and the vehicle attempted to reboot again while driving.

On 18 March 2026 I was driving at night at highway speed with my family (wife, [XXX] son, [XXX] daughter, and [XXX] son) when, without any warning, my 2023 GMC Sierra AT4 with 20,700 miles abruptly and violently shuddered and reduced speed from approximately 65 mph to 30 mph uncontrollably. Shortly after the initial speed reduction the vehicle presented simultaneous alerts that it was in "reduced acceleration mode", the "emission system control" had failed, and the that the check engine light was on. Although the vehicle claimed to be in reduced acceleration mode I was unable to prevent it from continuously slowing to 0 mph. I attempted to use the accelerator to move from the left lane of traffic to the right shoulder without causing an accident. However, the vehicle violently shuddered and would not accelerate or maintain speed. I managed to maneuver around traffic and stop the vehicle on the right shoulder. Due to the unlit highway and my family's emotional state after the incident, I determined the safest course of action was to attempt to get the vehicle to a nearby parking lot. After turning the vehicle off and back on, I managed to slowly drive with my flashers on (despite the vehicle continuing to violently shudder) approximately 1 mile to a Wal-Mart parking lot. Once there I noticed I received an email from OnStar Diagnostics that my vehicle experienced a significant engine malfunction with an associated P129F code. I coordinated for the vehicle to be towed to Bill Cramer Chevrolet GMC Inc in [XXX] the following day. My vehicle had no lights, messages, or symptoms of this issue prior to it occurring. The dealership replaced the fuel pump power control module under warranty, cleared the faults, test drove the vehicle, and returned to me on 31 March 2026. The dealer mentioned they service roughly two vehicles of similar make and/or models daily for the same issue. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2021 GMC Sierra 2500. The contact stated that while driving at 55 MPH, the vehicle stalled unexpectedly. There were no warning lights illuminated. The vehicle was taken to the local dealer, where it was diagnosed, and determined that the engine needed to be replaced. The engine was replaced; however, the failure recurred. While at a stop and attempting to drive around a curve, the vehicle stalled. No warning lights were illuminated. The vehicle was taken to the local dealer, where it was diagnosed with engine failure. The vehicle was not repaired. The failure mileage was approximately 77,000. The VIN was not available.

-The engine in my 2021 GMC Denali 1500 with the 6.2L engine failed its second engine with ~4,000 miles on the new engine. It is currently at GMC dealer waiting for a 3rd new engine. - Fortunately i was parked when the failure happened and the engine locked up. -Dealer confirmed that a valve dropped and damaged the cylinder wall. - There were no warning lamps or other indication that a failure was about to happen. -Current mileage ~91,000. First motor changed ~85,000 due to recall with previous owner.

There is a recall on the 6.2 motor that is in my truck at my last oil change they performed a pico scoop diagnostic on the truck said it passed and gave it the new type of oil and oil cap that was suppose to fix it. Now a couple months later I walk out start my truck to let it warm up and after starting all of a sudden the engine started nocking bad and loss of oil pressure and on dip stick. I looked it up and this is what happens when the engine fails due to the massive recall on the 6.2 engines. I called the dealer and they are having me tow the truck potentially at my expense for them to look at and decide if it falls into the category of the recall after they did the test, and at one point told me that cause they did the test it is no longer recalled. I am being told people who have had the engines replaced because of the recall that the replacement engines have failed as well. I have a 9 month old baby and this left me stranded and unable to pick him up from daycare I had to scramble to find somone able to do so. I'm concerned that this could have happened while driving and having him with me or being left stranded somewhere.I'm glad it didn't happen when I was dropping him off that morning and while I was driving And meanwhile while they look at the issue and decide weather this falls under there recall or not and while it gets repaired I'm left without a vehicle and to be honest I don't feel safe even if they do repair it as there seems to not be an actual fix to the situation. this is unsafe and unacceptable for the price we have to pay for these rigs and the safety regulations and standards we have, how is this even an issue.

The contact owns a 2019 GMC Sierra 1500. The contact stated that while driving at various speeds, the vehicle lost automotive power; however, the vehicle maintained electrical power. The check engine warning light was illuminated. The vehicle was towed to a local service center, where it was diagnosed and determined that the battery needed to be replaced. The vehicle was repaired; however, the failure reoccurred. The vehicle was taken back to the same local dealer and remained for additional investigation. The contact attempted to restart the vehicle several times and shift into different gears; however, the failure reoccurred. The local dealer was contacted, but the vehicle was not diagnosed or repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 103,000.