2025 GMC Sierra 1500

ENGINE STARTED KNOCKING AT 18K MILES AND TOOK TO DEALER AND THEY FOUND METAL IN THE FILTER AND INSTALLED A NEW ENGINE AND ALSO REPLACED THE MIDPLATE GASKET ON THE VALVEBODY DUE TO A HARSH DOWNSHIFT WITHOUT CODES IN THE SYSTEM THIS ENGINE IS GOING ON 2K MILES AND IT SEEMS TO BE FINE NOW BUT THE PROBLEM WITH 6.2 WAS ONLY SUPPOSED TO BE ON THE 21-24 MODELS AND MINE IS A 25 MODEL AND ALREADY HAD A REPLACED AND NOTHING FROM GM WAS SAID TO EXTEND THE WARRANTY ON THIS MODEL AND POWERTRAIN

I own a 2025 GMC Sierra 1500 Denali equipped with the 6.2L V8 L87 engine, VIN [XXX]. The vehicle had approximately 35,000 miles when the engine experienced a catastrophic engine failure. Prior to/during the failure, the vehicle experienced abnormal engine noise and a loss of power. Multiple warning/alarm lights appeared on the dashboard, including the Check Engine and Traction Control warning lights. The engine failure resulted in a loss of motive power and made the vehicle unsafe to operate. PHONE# [XXX] The sudden loss of engine power while driving created a serious safety hazard because the vehicle could no longer operate normally in traffic and could potentially cause a crash. I am requesting that NHTSA document and investigate this engine failure as a potential safety defect involving the GM 6.2L L87 engine. I am also requesting that NHTSA determine whether 2025 GMC Sierra 1500 vehicles equipped with this engine should be included in an appropriate safety recall or other corrective action. The vehicle is a 2025 GMC Sierra 1500 Denali with approximately 35,000 miles. The engine failure and warning lights occurred during normal vehicle operation. The vehicle and repair records can be made available for inspection, and I can provide dealer repair orders, diagnostic information, photographs, and other documentation concerning the failure. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

On July 25, 2026 when starting my vehicle, it began to shake violently and I receive numerous errors, including a check engine light and displays in the infotainment, indicating there were engine and transmission errors with the vehicle. I received a text message notification and in app notification from GMC indicating that there was a critical error and provided error code P0352. This appears to be an error related to a faulty engine, this is the 6.2L V8, which is known to be problematic by GMC. Had this happened while I was driving on the interstate three minutes later, it could’ve resulted in great bodily harm or death to both myself and the general public around me. GMC was later able to reproduce the issue at the dealer, confirming the faulty equipment on the vehicle with less than 16,000 miles on it. The component was replaced by the dealer, however, the vehicle is available for inspection.

While driving at highway speed, my 2025 GMC Sierra suddenly began slowing down without warning and lost propulsion. When I pressed the accelerator, there was no acceleration response. The vehicle felt like it was braking or dragging instead of accelerating, creating a serious crash risk in traffic. A warning message appeared instructing me to “Put in neutral and restart truck.” I followed the instruction, but the vehicle would not restart. It sounded like it was attempting to start, but it would not start normally. A “Service ESC” warning also appeared. The vehicle was towed by AAA to a GMC dealership and remains available for inspection. The dealership provided a diagnostic trouble code report showing active codes: C2A07 Engine Control Module Indicated Torque Signal Malfunction; U0101 Lost Communication with Transmission Control Module; U0131 Lost Communication with Power Steering Control Module; U0140 Lost Communication with Body Control Module; U0146 Lost Communication with Central Gateway Module; U160F Lost Communication with Brake System Control Module 1 on CAN Bus 1; U1611 Lost Communication with Engine Control Module on CAN Bus 2; and U3003 Battery Voltage Circuit Voltage Below Threshold. The vehicle had approximately 22,000 miles at the time of the incident. The failure has not been repaired at the time of this complaint. The concern appears to involve a safety-related electrical, propulsion, powertrain, ESC/brake, and module communication failure that caused sudden loss of propulsion, no acceleration response, warning messages, and a no-start condition.

Either while stopping while driving or parking (forward or reverse) the engine RPMs go up thus wanting to move the vehicle in that direction causing the breaks needing to be applied harder. When you shift into neutral the RPMs go way up (3000). This has happened on this vehicle 3-4 times of which I have video of the latest occurrence. When put into R or D the RPMs are still over 1000. This also happened on the courtesy vehicle same make and model) I was given but on this one the RPMs went up to 5000 of which I also have a video. The dealership has not been able to duplicate the issue as of yet. My fear is that the vehicle will hit someone or something if the break isn't pressed to the floor. It happens very randomly. The dealer currently has my vehicle trying to figure it out. They say GM says there's nothing they can do. No warning lights or messages appeared.

Rough idle started at 11,400 miles. Took to GMC dealer near me and had thrust bearing clearance measured. Measured .0054"(within spec). They released truck back to me. 19,400 mile oil change found large metal(non magnetic) slivers in the filter media. I cut filters to check for issues due to known issues with this engine(metal). I called gmc corporate, i was told to not drive the truck. I paid out of pocket for the tow 142 miles away. Dealer told me they checked thrust bearing and came in at .0055", no noises, and no check engine light. Idle is very rough on start up. GM corporate stated a service advisor will call. Never got a call. I have sent and displayed the evidence and offered to show oil filter contents to both dealer and corporaten both have not done anything about this safety issue. This is a SEVERE safety issue. Engine is highly likely to lock up and cause serious injury to both me, my family, and others on the road. Dealer has released truck back to me and my family with clean bill stating they didnt find anything wrong. They refused to see my documentation of metal slivers or the 3 rimg binder full of maintenance records. As of now i will be escalating this to higher up in GMC corporate. SEVERE safety risk for my family and everyone on the road. GMC dealers refusing to diagnose.

In normal operation on Tuesday May 26,2026, the engine experienced catastrophic failure. The engine is the GM L87 6.2 Liter. This was on a highway in the country and I was able to maneuver the truck off the road before an accident occurred. It did leave me stranded and I was required to get it towed on a roll off (It was not drivable) to the dealer where I purchased it. The dealer [XXX] ) inspected my truck and has informed me that the issues with my 2025 Sierra match the issues for the recall GM had for the model years 2021-2025. It will require a new engine, radiator, among many other parts. There weren't any previous warnings. A check engine light only came on once the engine was engine came apart. An oil change on the vehicle by GM was done a month ago. The truck is a 2025 and has approximately 6,600 miles is all. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Truck does not automatically shift into park when the door is opened. Getting out of my truck, I forgot to shift into park and opened the door, and the truck moved forward with automatically shifting into park, or applying the parking brake. I have a 2015 Jeep Grand Cherokee that did the same thing. There was a safety recall set forth by the NHTSA to have the car go into park when the door opened to prevent someone for being run over by the vehicle. My 2025 GMC Sierra is experiencing the same issue. I was not harmed, but can definitely see someone getting hurt.