The contact owns a 2023 GMC Yukon XL. The contact stated that while driving on several occasions at various speeds, the vehicle experienced unexpected gear shifting. The check engine warning light illuminated and then disappeared when the vehicle was restarted. The vehicle was not diagnosed or repaired. The contact used a handheld diagnostic machine and retrieved DTC: P0747. The manufacturer was notified of the failure. The failure mileage was 67,000.

The vehicle has the L87 GM engine. It lost complete power and the engine seized up and would not start again. Fortunately I was able to roll into a neighborhood and get off the main road with no issues. The dealer has confirmed the seized engine and a replacement engine has been ordered with no ETA. There was no prior warning of the failure, besides a shuddering, like I was running out of gas, and then a lose of complete power.

Drove vehicle to town and back, 20 mile round trip. When entering my property, the Engine stalled while pulling into driveway. Upon cranking, was very hard to start. When taking the next trip after engine stall, vehicle died in motion at 60mph approaching a traffic intersection with no warning, leaving very little time to navigate to the shoulder and off the roadway. Engine will not crank over, suspect Engine has failed again, currently at dealer awaiting diagnostics. No lights, warnings, noises or indications of Engine failure were observed during the drive cycle.

The panoramic sunroof on my 2023 GMC Yukon Denali Ultimate XL spontaneously exploded while driving westbound on I-20 on March 13. There was no impact from road debris, no vehicles ahead, no overpass, and no external cause. The failure sounded like an explosion or gunshot. Tempered glass shattered with the sunroof in the closed position, showering the interior with glass fragments. Five occupants were in the vehicle at the time. No injuries occurred, but the sudden explosive noise and shower of glass created an extreme distraction and safety hazard while operating the vehicle at highway speed. The incident could easily have caused a loss of vehicle control on the interstate. The component that failed is the factory-installed panoramic power sunroof glass, standard equipment on the Denali Ultimate trim. The vehicle was taken to Lugoff Chevrolet for inspection. The dealer confirmed the glass failure and submitted a request to GM for warranty or goodwill coverage. GM offered to cover only 10% of the repair cost, characterizing the failure as an out-of-warranty wear issue despite the spontaneous nature of the defect. There were no warning signs, cracks, chips, warning lamps, or any indication of a problem prior to the failure. The sunroof was closed at the time. The vehicle has been dealer-maintained with no modifications to the sunroof or roof structure. This is a known industry-wide defect. NHTSA has previously investigated spontaneous sunroof shattering and documented over 4,000 complaints. GM has acknowledged awareness of this issue in other GM vehicles and previously issued corrective actions for sunroof glass on the Buick Regal and Chevrolet Cruze. Other GMC Yukon owners have filed NHTSA complaints describing identical failures. The failed sunroof glass and vehicle are available for inspection upon request.

I own a 2023 GMC Yukon Denali. In Nov. 2023, at about 4,000 miles, the vehicle suffered a complete engine and electrical failure at highway speed while I was traveling with my husband and three small children. It suddenly lost all power in the fast lane, including acceleration and engine function. Steering became extremely heavy, consistent with loss of power steering assist, and the electronics shut down. We had to guide the vehicle across traffic while coasting downhill to the shoulder beyond a guardrail. Traffic had to avoid us, creating a serious safety hazard. The vehicle would not restart. The vehicle was towed and required a complete engine replacement under warranty. After that replacement, additional issues followed. There was an HVAC/defrost concern. In June 2025, the vehicle again became inoperable without warning while parked at a store. It would not start despite repeated attempts, including by a dealership representative. A diagnostic scan produced over a page of error codes, but the dealership could not identify a cause and stated the vehicle was safe. In Dec. 2025, the vehicle engine was inspected under a recall and I was told there were no issues. In Feb. 2026, the vehicle lost heat and was found to have no coolant despite regular maintenance and recent inspection. In Mar. 2026, at about 37,700 miles, the vehicle developed a loud clunking noise while driving. I stopped driving and returned it to the dealership, where I was told the engine had failed again and required another full replacement. The vehicle has now had two engine failures and three engines installed in less than three years. There were no warning lights or prior indications before these failures. I no longer believe this vehicle is safe or reliable for transporting my family.