2021 GMC YUKON Complaints

Lifter failure with cylinder #6. Car violently shook prior to this failure. No engine lights or messages until the next day when tried to drive. Ended up towing car to dealer. Car had 76k miles on it. Recall on 6.2L, but not on the 5.3L which is not immune to this same issue as the 6.2L engine.

The vehicle shifted into Neutral while driving, locked out gear selection, triggered a transmission warning, and now will not restart.

On December 1, 2025 at around 5pm CST, my 2021 GMC Yukon XL started making a squeeling noise then stopped while driving down the road. It left me stranded in the middle of the road. A P0016 CODE was produced and the engine light came on. I had the vehicle towed the next day to Stew Hanses GMC in Clive, Iowa. The engine was torn down for inspection and was told the rod bearing went bad and it had low oil even though I was within the window since the last oil change and having documented all necessary required maintenance. I was told the engine needs to be replaced and am in the process currently of Stew Hanson GMC replacing all necessary parts. I was told I do not have a recall on the vehicles vin number by GMC corporate and the GMC dealer. It is coming up on a month since the incident happened and vehicle towed to dealership. I do not have pictures from the dealer yet or final invoice as this is still in process. I wanted to document this somewhere.

traction control system ESC system Suddenly and without warning, multiple warning lights started flashing including check engine. The vehicle lost power and traction. There was a loud knocking and metallic whining sound. The vehicle began to vibrate and struggled to move forward and felt like the wheels were slipping. The loss of these functions was alarming because it was dark, we were in a construction zone, and my 15-year old daughter was driving having recently earned her driver's permit. The car following us almost rear ended us. It was such an abrupt engine failure it scared me and my daughter.

Vehicle: 2021 GMC Denali Mileage: ~48,000 miles Purchase Price: $62,000 Issue: Airbags & crash sensors failed to deploy Complaint Text: I am filing a safety complaint regarding my 2021 GMC Denali. I was involved in a rear-end collision at approximately 45 mph, where I struck another vehicle straight on from behind. The impact was severe enough to total my vehicle, yet no airbags deployed, and no forward collision warning or crash sensor systems activated. This is especially concerning because this vehicle was previously involved in a front-end collision (not my fault) and underwent extensive repairs. I was assured all systems were repaired and functioning properly. Additionally, my vehicle had completed recall work related to safety systems prior to this crash. This is the second front-end crash involving this vehicle where airbags failed to deploy. Given the speed and severity of the impact, airbags should have deployed. The failure of these systems placed my life at serious risk. The vehicle has since been totaled and taken by insurance, but I am requesting that this failure be formally investigated as a potential safety defect in the airbag and sensor systems. I am extremely concerned that the vehicle’s safety systems were either defective or not properly restored following repairs and recalls.

The contact owns a 2021 GMC Yukon. The contact stated that while driving at an undisclosed speed, the contact noticed that the front windshield was extremely blurry. In addition, the contact stated that it was a safety failure, especially while driving at night. The contact stated that while driving at night, the failure was extremely unsafe. The vehicle was taken to the dealer, and it was confirmed that the front windshield was defective. The contact was informed that the front windshield needed to be replaced. The vehicle was not repaired. In addition, the failure occurred previously in June 2023, and the repair was covered under warranty. The manufacturer was made aware of the failure, and a case was filed. The repair was denied. The failure mileage was approximately 25,000. The VIN was unavailable.

While driving my 2021 GMC Yukon?XL, the vehicle unexpectedly lost acceleration. After lifting off the gas pedal, it jolted forward, triggered a “Reduced Performance” dashboard warning, and remained in what felt like second gear, refusing to shift. I immediately pulled into a parking spot; when I attempted to reverse, the vehicle would not move backward. As you may imagine, this was a major safety concern, as I had my [XXX] and [XXX] children in the vehicle with me. I had the Yukon inspected at a GMC dealership, where a technician confirmed the issue originated from a faulty transmission valve body. My independent research has revealed this to be a widespread defect in the 2021 Yukon XL, prompting GM to issue Special CoverageXXX, which explicitly covers valve-body replacements for 2021 Yukon XLs experiencing reduced performance. Despite meeting these criteria and receiving identical diagnostic alerts, I was informed that my VIN is not covered. I am formally requesting that this safety-related defect—widespread among this model year—be recognized and my VIN included under Special Coverage XXX. The valve body causing the loss of propulsion in my Yukon XL is exactly the same defective component GM has acknowledged and is covering under this program. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2021 GMC Yukon XL. The contact stated that while driving at 30 MPH, the gear shifter independently shifted to neutral(N), and the vehicle speed decreased. The contact stated that upon depressing the brake pedal, the vehicle lost drive power. The vehicle was towed to the dealer, where it was diagnosed, and the dealer determined that the engine needed to be replaced. The vehicle was not repaired. The contact related the failure NHTSA Campaign Number:25V274000 (Engine and Engine Cooling); however, the VIN was not included in the recall. The manufacturer was notified of the failure and filed a case. The contact was also referred to the NHTSA Hotline to file a complaint. The failure mileage was 120,000.

After noticing a "groaning/moaning" sound from the vehicle when turning sharp at low speeds the vehicle was brought into a dealership to be inspected. After inspection, the mechanic stated that the sound is coming from the rear differential and that it would need to be flushed/cleaned up to three times as a potential correction. If the clean/flush does not correct the issue, they would need to replace the entire rear differential. When asked what happens if the rear differential fails, we were advised that we could experience total failure and lock up. This is a safety issue in that if we are driving and the wheels lock up the potential for collision or major accidents is high. I also understand that the differential is meant to last the life of the vehicle and had 123k miles, the life of the vehicle is far from over. Another issue we are experiencing is excessive oil burning. The vehicle "add engine oil" light comes on after 2,500 miles when being regularly maintenanced. The vehicle should not require the addition of oil after that many miles, more so should not require oil at all unless you weren't properly maintaining the vehicle (which is not the case). I understand issues arise and things happen; I just want this to be acknowledged as a potential safety issue and corrected. Thank you,

Freedom, tire and automotive Inc. advised my 6.2LV8 engine has failed due to metal debris found in the new oil, indicating a mechanical failure of an internal engine component. I called GMC and they referred me to you.