GMC Sierra Complaints (2026)

171 consumer complaints on file.

#11774398October 29, 2026
FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL, FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING, FORWARD COLLISION AVOIDANCE: WARNINGS
I am filing a formal safety complaint regarding my 2026 GMC Sierra 2500HD Duramax (VIN [XXX]; 32,607 miles). While driving at highway speeds with Adaptive Cruise Control engaged, the truck intermittently applies the brakes suddenly and forcefully with no vehicle, pedestrian, or obstruction apparent in the roadway. On some occasions it decelerates from my set cruising speed to nearly a complete stop without my braking input or warning. This creates an immediate risk of a rear-end collision, particularly in highway traffic. These events have occurred repeatedly. The brake rotors now exhibit warping or vibration, which I suspect may be related to the repeated severe braking; the cause has not been established. My previous 2025 GMC Sierra 2500HD Duramax experienced similar unexplained braking. I reported concerns but did not receive a satisfactory investigation and traded it at approximately 35,000 miles, believing the issue was isolated. The 2026 truck's behavior is worse. I purchased another GM truck without these features to maintain dependable transportation because I do not consider using Adaptive Cruise Control on this vehicle safe. I have located seven distinct online owner reports of similar unexpected braking in recent GMC Sierra and related Chevrolet Silverado trucks, including reported NHTSA complaint XXX; these reports have not been independently verified as the same defect. I request that NHTSA investigate potential false detection or unintended braking commands involving Adaptive Cruise Control and related systems on 2024–2026 GM trucks, obtain GM engineering and warranty records, and evaluate the risk to drivers and following traffic. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11773709October 26, 2026
STEERING, ELECTRICAL SYSTEM
My 2026 GMC Sierra AT4 HD intermittently has no power steering assistance when I start the vehicle, making it extremely difficult to steer. This occurs randomly, approximately once every one to two weeks, and has nearly caused me to hit another vehicle on multiple occasions. A few months ago, the dealership inspected the truck, performed a software update, and told me the issue should be resolved. However, the same problem occurred again after that service visit. I contacted the dealership and requested another service appointment and a loaner vehicle because I need transportation to work. I was told there is a waiting list for loaners. GMC customer service has opened a case and is contacting the dealership to help arrange service sooner. The steering issue remains unresolved, and I am concerned it could cause a collision.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11773272October 23, 2026
ELECTRICAL SYSTEM, ENGINE
Three different times now (most recent: 10/22/2026), I have had my truck completely shut off when coming to a stop on the highway/interstate. I always have auto start/stop disabled when I drive. When it happens, a message shows on the dash that says press start button. No other codes or check engine light. Thankfully it has started every time, but this is obviously a serious safety concern. After the second time it happened, I had the dealer (Woodhouse Buick GMC Omaha) look at it on 9/14/2026, but they couldn't find anything since there were no codes. I'm not sure if it is an electrical issue or this is related but my audio will stop working at times as well. Nothing from the radio or any blinker sounds. Sometimes it's static with a high pitch noise. 2026 GMC Sierra Elevation 5.3 EcoTec3 v8 10 speed
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11772895October 22, 2026
ELECTRICAL SYSTEM
The contact owns a 2026 GMC Sierra 1500. The contact stated that while the vehicle was stopped, the GPS was not operating as intended. The system failed to update after 15 minutes. The vehicle was difficult to start and had failed to start on another occasion. The vehicle was taken to the local dealer, and an update was forced and the battery was charged. The vehicle was scheduled for a fourth repair. The failure mileage was approximately 7,329.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11772611October 21, 2026
ENGINE
I had driven about 30 minutes on the Interstate at highway speeds and had just exited the Interstate and the truck made a horrible noise, shut off, and the transmission threw itself into park at about 10 mph. At this time, the engine did not want to restart, but did eventually and I had a check engine light on, but I was able to move the truck out of the intersection so that I could be towed to the dealership. Prior to the incident, there were no check engine lights and the vehicle had only been serviced at a GMC dealership. I was very uncomfortable with the way the truck stopped and slammed into park. I am happy that no one was behind me, but it could have been bad. The vehicle has not been inspected yet to my knowledge.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11772705October 21, 2026
ELECTRICAL SYSTEM, ENGINE, POWER TRAIN
While driving the truck it randomly shuts down, message on dash says shift to park to restart. No check engine light comes on or any other message. When it does this, the truck goes into park. It has been to the dealership 3 times and has not been fixed!
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11772532October 20, 2026
ELECTRICAL SYSTEM
Vehicle experienced a complete loss of audio, to include warning chimes, bluetooth audio, radio, and blinker on/off notification warning. This can be a serious issue because without hearing the click notification That your blinker is on, another vehicle may think you are turning and pull out in front of you, possibly causing a serious crash
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11772037October 19, 2026
UNKNOWN OR OTHER
While driving, the vehicle audio system intermittently loses all sound for approximately 1-2 seconds. During the audio loss, entertainment audio, turn-signal click sounds, and vehicle warning chimes all disappear simultaneously and then return. Vehicle is currently running infotainment software version 662.11. Issue occurs while driving and has happened multiple times. Concern is that loss of warning chimes and turn-signal sounds may reduce driver awareness of safety-related notifications. During complete audio loss (Blinkers, chines, etc), vehicle needs to be shut off for several minutes to recover audio loss.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11772182October 19, 2026
ENGINE
I am writing to formally request that General Motors repurchase my 2026 GMC Sierra 1500, currently with approximately 9,445 miles, due to a serious and unresolved mechanical defect that poses a significant safety risk. Since purchasing this vehicle, I have experienced four separate incidents involving a complete and unexpected loss of engine power, causing the truck to become inoperable. In each instance, the vehicle suddenly lost propulsion and came to a stop without warning. While three of these events occurred while operating the vehicle near my residence, one incident occurred while I was attempting to merge onto a highway. Fortunately, traffic conditions at the time prevented a collision or serious injury. However, the sudden loss of power while entering a highway created an extremely dangerous situation and exposed both myself and other motorists to substantial risk. The vehicle has now been at the selling dealership for nearly one month while technicians attempt to diagnose and repair the issue. To date, I have not been provided with a definitive root cause or a permanent corrective action. The lack of resolution, combined with the recurring nature of the defect, has resulted in a complete loss of confidence in the vehicle's safety and reliability. My concerns are heightened by information suggesting that similar issues may have been experienced by owners of comparable GMC Sierra vehicles. Regardless of the ultimate root cause, the fact remains that my truck has repeatedly exhibited a condition that can unexpectedly disable the vehicle while in motion, creating an unacceptable safety hazard. I purchased this truck with the expectation that it would provide safe, dependable transportation. Unfortunately, after four loss-of-power events and an extended period in the repair facility without a successful resolution, I no longer believe this vehicle can safely fulfill that purpose.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11771425October 15, 2026
ENGINE, POWER TRAIN, SERVICE BRAKES
On 10/15/2026 I was making a slow right-hand turn up a slight incline into a parking lot when the vehicle braked very hard and the transmission made a grinding noise. I looked at the dashboard, and it was showing that the truck shifted into park while I was driving. The electronic brake engaged as well. I tried putting the truck back into drive, but it would not go into drive. On the dash there was a Service Transmission warning. The push to start engine button still had the green LED on as if the vehicle was running. I pushed the start engine button and the engine started (I didn't realize until now that the engine had shut off). At this point the truck would shift into drive. Another point of note is that I had turned off the Auto Stop feature. I do this every time I start my trip. The truck will be looked at on 10/16/2026 by the dealership. I did report the problem to the service department of the dealership. This incident was the first time it ever happened and there was no warning.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11770798October 13, 2026
ELECTRICAL SYSTEM
Since I purchase this truck I've been having no audio twice a week. Dealer has no fix GMC knows they have issues and still they are selling this vehicles. Took a trip to [XXX] a storm was moving in and we had no audio to alert us I also believe with no audio we have no blinkers we almost cause an accident. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11770641October 12, 2026
ENGINE, VEHICLE SPEED CONTROL
I was approaching an intersection about to make a left turn as the turn signal was flashing yellow and my truck just stopped accelerating. If i had taken that turn i would have got hit and most likely cause a huge pile up because the amount of traffic going through. I put my hazard lights on and tried shifting my truck into park, and then back into drive, and it would not accelerate. I had to turn my truck off and on a few times for it to accelerate. There were no warning lights on my dash and the truck is brand new.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11769781October 8, 2026
ELECTRICAL SYSTEM, ENGINE, POWER TRAIN
5/08/2026: I stopped outside my garage. I then placed the truck in park and exited the vehicle while running. I went inside my garage and several minutes later, heard a crash. The truck had driven forward while unattended, and crashed into the corner of my garage, causing damage to both the building and the truck. Truck indicated it was still in park upon reentry. 5/11/2026 In a separate incident 3 days later, while driving at approximately 50mph, truck engaged in an automatic braking event with no discernible cause. Simply applied what felt like 100% braking for a split second, then released. 5/12/2026: Truck taken to GMC for investigation. No codes in any modules detected. 9/20/2026: Vehicle reports transmission fault, states it should not be driven. 9/21/2026: Towed to GMC dealer. Found codes P17A8 and P189D and diagnostic code 6906361, internal fault within gearshift control module. Requested GMC pay for damage resulting from collision, as clearly the unattended driving appeared related to gearshift control, but was refused. GMC stated that unattended driving was not possible and did not result from the detected failures.
Crash:
Yes
Fire:
No
Injuries:
0
Deaths:
0
#11769352October 6, 2026
STEERING
The contact owns a 2026 GMC Sierra 3500. The contact stated that while driving 2 MPH, the steering wheel failed to function as intended. The contact stated that while making a right turn, the vehicle hesitated. The dealer was contacted by phone and made aware of the failure. The vehicle was taken to the dealer and the contact was informed that the vehicle was operating as designed. The contact stated that the failure was not present when the vehicle was purchased. The manufacturer was contacted, and a case was filed. The failure mileage was approximately 4,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11769460October 6, 2026
ENGINE, ELECTRICAL SYSTEM
We bought the vehicle on February 28th and on March10th my husband was driving on his way to work on the I95 highway and the engine shut down. My husband was in the middle of the highway with a speed limit of 65. Traffic was able to slow not to cause any more accidents however he had to be towed and GM replaced the engine. Because it had not been 30 days in the shop. Due to GM abiding by Lemon laws we were not able to qualify for a buy back. We have been fighting with them ever since. I was able to get a reimbursement of my first car payment. However, my husband is a general contractor and is absolutely terrified to accept jobs far away because we don’t know when the truck engine might give up again. All of the charging ports stop working a couple of weeks ago, we had to take it in for repairs. This is a $78,000 vehicle with 4 miles on it when we purchased it. I don’t know what it is worth now because the engine was replaced with in 10days of purchasing it. I need help!!!!!!!!!!
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11769205October 6, 2026
SERVICE BRAKES
At 20 mph, the truck experienced unintended acceleration during normal braking. Light braking did not trigger the safety brake-override system, and the engine continued to pull forward until I was forced to mash the brake pedal completely down to overpower the engine.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11769243October 6, 2026
ENGINE, FUEL/PROPULSION SYSTEM, POWER TRAIN
While driving on a public road, the 6.2L L87 V8 stalled without warning. There was heavy smoke and an oil trail of about 300 yards behind the truck. The engine would not restart, and the transmission would not shift into neutral. The truck was moved a short distance off the road and towed the next day to the selling GMC dealer. Odometer was 4,663 miles. Oil life remaining was 38 percent. The truck was stock, with no modifications, and was operated on premium fuel. No warning lamp was noticed before the stall. The failed engine is at the dealer and currently under inspection. The dealer inspection is not finished, and no written cause has been provided. This is a sudden loss of propulsion. Please associate this report with Engineering Analysis EA26005 concerning connecting-rod and crankshaft failures in the GM 6.2L L87 engine.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11769298October 6, 2026
ENGINE
Engine had catastrophic failure at only 1,433 miles driven. Incident happened on the interstate and truck was required to be towed to the dealer. Dealer said engine replacement is necessary.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11768920October 5, 2026
ENGINE
The 6.2L engine died at 8,300 miles. It took the dealership 6 weeks and would not give me a repurchase lease buyback. They put a new engine in, but I’m hearing that they didn’t really fix the problem and this is just a new version.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11769188October 5, 2026
ENGINE
On September 29, 2026, I was driving my GMC Sierra 1500 on the highway at approximately 15 mph due to construction when the truck suddenly lost acceleration. Engine warning messages appeared, the vehicle automatically shifted into neutral, and the engine completely shut off while I was driving. A message instructed me to restart the engine. I attempted to restart it, and the truck eventually turned back on, although it was difficult to start. I was able to carefully drive the vehicle home. This was extremely concerning because the sudden loss of propulsion and engine shutdown occurred while I was on a highway and could have caused a serious accident, especially at normal highway speeds or in heavier traffic. I took the truck to Cavender GMC on September 30, 2026, for inspection and diagnosis. Still pending on results. I am especially concerned because there are ongoing NHTSA investigations, consumer complaints, and litigation involving certain General Motors vehicles and reported engine failures that can result in sudden loss of propulsion. Some reported incidents involving GMC Sierra 1500 vehicles describe symptoms similar to what happened to my truck, including loss of acceleration, shifting into neutral, engine shutdown, warning messages, and the need to restart the vehicle. I understand that my truck may not necessarily be affected by the same issue or included in any lawsuit. However, because of the similarities, I am requesting that GMC and Cavender GMC thoroughly investigate whether this incident is related to any known engine, powertrain, electrical, software, or safety issue affecting this vehicle. I am requesting that the underlying cause be identified and properly repaired before the vehicle is considered safe to return to service. My primary concern is safety, and I need confidence that the truck will not unexpectedly lose propulsion, shift into neutral, or shut off again while I am driving.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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