2025 GMC Sierra 1500

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)

Cruise control activates at speeds between 1-5mph, which frequently happens while turning, parking, or going through a drive-through. The cruise control activates by a toggle on the left spoke of the steering wheel, which can be easily bumped while doing low-speed maneuvers like parking. When bumping the toggle, the cruise indicator shows a set speed of 15-18 mph, and the vehicle surges forward trying to attain that speed. Since this occurs while maneuvering to park, it creates a dangerous situation if anyone is nearby and you are unable to react in time. This is an ongoing problem that can be duplicated at will. Rear backup camera very dark at night it’s unusable.

First occurrence was 02/27/2026 - onstar detecated a critical issue, the check esc, check tsc words came on in the center dash, then the orange lights came on and my truck went into limp mode at a stop light. I had to limp mode a mile to the nearest dealer. Where nothing was repaired just reset. Second occurrence - exhaust flap valve failed creating chirping noise resulting in a muffler replacement on 04/28/2026 - picked the vehicle up on 04/30/2026 Third occurrence - 05/01/2026 came out after a wedding to start my truck which it immediately repeated the first occurrence, check esc, check tsc with the orange lights and chugging. recorded on camera now the trucks been at the dealership awaiting updates.

Cruise control activates at speeds below 2 mph which frequently happens while turning or parking. The cruise control activates by a toggle on the left spoke of the steering wheel which can be easily bumped while doing low speed maneuvers like parking. When bumping the toggle the cruise indicator shows a set speed of 15mph and the vehicle surges forward trying to attain that speed. Since this occurs while maneuvering to park, it creates a dangerous situation if anyone is nearby and you are unable to react in time. This is an ongoing problem that can be duplicated at will.

The contact owns a 2025 GMC Sierra 1500. The contact stated that while tapping the accelerator pedal, the vehicle suddenly accelerated. The contact stated that the tires were squealing. The contact drove over a cement barrier after depressing the accelerator pedal. There were no warning lights illuminated. The local dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer was contacted but no assistance was provided. The failure mileage was approximately 7,800.

I am writing to express my extreme disappointment and serious concern regarding a critical safety failure I experienced with my 2025 GMC Sierra 1500 Denali Unlimited (VIN: [XXX] ), which I purchased brand new in April 2025 from Cavender GMC, San Antonio, TX. On Friday, [XXX], with fewer than 9,000 miles on the vehicle, I was driving on the highway at about 65 MPH, with my minor son in the vehicle when the dash suddenly displayed a Traction Control (TRC) Fault message, followed immediately by "Acceleration is Limited." The truck experienced a severe and unexpected power loss, severely restricting my ability to accelerate or maintain safe highway speeds. I was forced to pull off the road abruptly to avoid a potentially dangerous situation. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2025 GMC Sierra 1500. The contact stated while driving approximately 4 MPH and turning left into a parking spot, the vehicle independently accelerated. The contact stated that the brake pedal was depressed. The contact stated there was no warning light illuminated. The contact stated that the failure was intermittent, but the failure occurred while slowing down under 5 MPH and turning to the left. The contact had taken the vehicle to a local dealer; however, the failure was not duplicated. The vehicle was not repaired. The manufacturer was informed of the failure. The failure mileage was approximately 17,000.