2021 GMC YUKON XL Complaints

While my [XXX] son was driving my 2021 GMC Yukon Denali XL, the engine failed suddenly without warning. The vehicle lost power completely and became inoperable, leaving them stranded far from home. This posed a significant safety risk to my family, especially given the location and time of day. There were no warning lights or messages prior to the failure. The vehicle was towed to a GMC-certified dealership, where the issue was diagnosed as a complete engine failure. The dealer confirmed that internal engine components were damaged and the entire engine required replacement. The dealership performed the repair and confirmed that the issue was consistent with known defects now acknowledged by GM in their 2025 recall affecting vehicles with the 6.2L V8 engine. The problem has been reproduced and confirmed by the dealership. The defective engine is no longer available for inspection, as it was removed and replaced during service. The repair was performed at my personal expense prior to the recall. 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 while driving approximately 45–50 MPH, the engine was making an abnormal sound. The contact stopped and lightly depressed the accelerator pedal and continued driving. The contact stated that the transmission failed to shift gear. The RPM increased to high. The check engine warning light was illuminated. The vehicle was taken to the local dealer where it was diagnosed and determined that the transmission needed to be replaced. The vehicle was repaired under warranty, but the failure recurred. The vehicle was taken back to the same dealer who determined that the failure was related to the transmission. The vehicle was repaired but the failure persisted. The vehicle was taken to another local dealer, Hennessy GMC (145 Industrial Blvd, McDonough, GA 30253); where it was diagnosed and the contact was informed that the transmission needed to be replaced. The vehicle was not repaired. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 66,000.

The contact owns a 2021 GMC Yukon XL. The contact stated that while driving at various speeds, there was grey smoke coming from the exhaust pipes. The check engine warning light was illuminated. The vehicle was taken to a local dealer where it was diagnosed and determined that the engine needed to be replaced. The vehicle was not repaired. The vehicle was taken to a local independent mechanic for a second opinion, and it was diagnosed and determined that the engine and brake pads needed to be replaced. The vehicle was not repaired. Upon further investigation, the contact related the failure to an unstated recall; however, the VIN was not included. The manufacturer was made aware of the failure. The failure mileage was approximately 125,000.

Vehicle has almost 75000 miles. No warnings whatsoever, the GMC app actually reported the vehicle has no issues and all systems are working. The engine began to knock, the transmission was not shifting well, traction control stopped working. Took the vehicle to the local dealership who called me and said it was complete engine failure that is going to require a brand new engine. All of the maintenance is up to date.

Transmission issue - 2021 Yukon XL broke down 5/6/25 while driving with 2 of our children in the vehicle. the RPMs skyrocketed but the vehicle wouldn't go. was hard shifting and speed would not exceed 35ish MPH. message popped up on vehicle that said acceleration throttled and engine light came on. Took it to dealership and it is a known problem. Transmission needs a valve body replacement. This part is on national backorder for months. Spoke with the dealership on 6/5/25 and they still do not have an ETA. They ordered one on 3/19/25 that still has not arrived. I received a case number from GM but they are extremely unhelpful.

Subject: Formal Complaint – Engine Failure in 2021 GMC Yukon Denali XL VIN: [XXX] Defect Number (GM): [XXX] GM Case Numbers: [XXX] / [XXX] / [XXX] Dear NHTSA Office of Defects Investigation, I am writing to formally report a critical mechanical failure in my 2021 GMC Yukon Denali XL, which resulted in a complete engine failure, rendering the vehicle inoperable and exposing my family to significant safety and financial risks. Despite following the recommended maintenance schedule and driving under normal conditions, the engine failed prematurely. The vehicle has been out of service for over four months, and I have yet to receive a definitive resolution or timeline from General Motors. I have incurred over $13,000 in out-of-pocket costs, including towing, repair estimates, rental vehicles, and continued loan payments on a non-functional vehicle. Key Details: Vehicle: 2021 GMC Yukon Denali XL VIN: [XXX] Failure Type: Total engine failure requiring full rebuild or replacement Time Out of Service: 4+ months and ongoing Financial Impact: $13,335.58 in documented costs GM Defect Number: [XXX] (noted internally by GM) Dealer(s) Involved: Midas Auto Service, Beaman GMC (Nashville, TN) I have made repeated efforts to escalate this through GM’s Case Advisors and Executive Team, but have received no meaningful resolution or written acknowledgment of my request for either reimbursement or a good faith vehicle buyback. Given the safety implications of such a catastrophic failure in a relatively new vehicle, I believe this may represent a broader manufacturing defect or quality control issue and warrants NHTSA investigation. I respectfully request that NHTSA: Log this complaint into your safety database Investigate whether similar failures have occurred in other 2021 Yukon Denali XL vehicles Contact GM for further information regarding this defect and associated safety risk Thank you for your attention to this matter. 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 when the vehicle was started, there was a loud sound coming from the engine compartment. The contact stated that when the vehicle was driven around the block, the sound was still present coming from the engine compartment. The vehicle was taken to an independent mechanic where an oil change was performed but the failure persisted. The vehicle was then taken to the residence. The vehicle was next taken to a dealer where it was diagnosed, and metal shavings were found in the oil, possibly coming from the crank bearing or connecting rod bearing. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 100,371.

In March 2025, a situation happened to me during a six hour round trip drive. I experienced a loss of acceleration. Vehicle engine felt it was stumbling when accelerating or seemed like I had ran something over. I don't remember seeing any lights coming on. Pulled over immediately, turned off the vehicle. Turned it back on and drove back home three hours worried it may happen again. I didnt see any warning lights on the trip.

The contact owns a 2021 GMC Yukon XL. The contact stated while her husband was driving at an undisclosed speed, the engine made an abnormal loud sound, and the vehicle became undrivable. The vehicle was taken to Midas, where an unknown repair was performed. Additionally, the contact stated while driving 50-55 MPH on the expressway, the vehicle shuddered significantly, and the engine made an abnormal loud knocking sound. Unknown warning lights were illuminated. The contact was able to exit the expressway and drove back to Midas, where the contact was informed that the engine needed to be replaced, and the mechanic provided an estimated fee for the repair. The vehicle was towed to the dealer, where it was diagnosed that the engine needed to be replaced; however, the part was not available. The vehicle remained at the dealer for approximately three months. The vehicle was not repaired. The contact related the failure to NHTSA Action Number: PE25001(Engine, Engine and Engine and Cooling). The manufacturer was notified of the failure and informed that the part was not available. The failure mileage was approximately 73,000.

Rear view camera fails to display on screen when vehicle is shifted to reverse. Failure remains during the remainder of ignition on cycle. The failures does not generate system error codes. Dealer service unable to diagnose failure