2026 GMC Sierra 1500 engine problems

Filed Nov 5, 2026 · Engine · OR

See attached document for complaint.

Filed Oct 23, 2026 · Electrical, Engine · NE

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

Filed Oct 21, 2026 · Electrical, Engine · IL

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!

Filed Oct 21, 2026 · Engine · NE

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.

Filed Oct 19, 2026 · Engine · TX

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.

Filed Oct 15, 2026 · Brakes, Engine · TX

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.

Filed Oct 12, 2026 · Acceleration, Engine · GA

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.

Filed Oct 8, 2026 · Electrical, Engine · FL · crash

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.

Filed Oct 6, 2026 · Electrical, Engine · MD

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!!!!!!!!!!

Filed Oct 6, 2026 · Engine · FL

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.