What 295 owners told NHTSA about the 2021 GMC Yukon Denali Xl 1500

2 days after the delearship changed my oil to a heavier weight, my engine began knocking. I’m told the rod is bent but not covered by warranty

NHTSA ODI 11715102

In 2024, while the vehicle was still under warranty, we brought it to our GM dealer due to an air suspension fault. The problem typically occurs in extreme cold weather, and following that visit, we did not experience further issues during the remainder of that winter as it was never that cold again. However, the following winter the same issue returned and was diagnosed yet again, and this year we are again experiencing the identical problem with the same diagnostic code which has been diagnosed by 2 dealers and a private mechanic in the last week. It has since become clear that the underlying issue was never properly repaired during the 2024 warranty visit. We recently learned that approximately 3.5 weeks after our 2024 service appointment, GM released a service bulletin outlining the correct repair procedure for this exact issue. We were not notified of this bulletin by the original servicing dealer. This information only came to our attention when we brought the vehicle to a GM dealer last week, where the issue was properly diagnosed and now they are refusing to fix it without us paying $4300 even though it was brought to their attention in 2024 while under warranty. A failed air suspension presents a safety concern, not merely a ride-comfort issue. When the system fails, the vehicle may sit unevenly or at an incorrect ride height, which can affect vehicle stability, steering response, braking geometry, and traction—particularly in cold weather and at highway speeds. Because the failure is intermittent and temperature-related, it is unpredictable and increases the risk of loss of control. The vehicle is not operating as designed when the air suspension is compromised. GM knows about this issue as they did indeed issue a bulletin that covers our vehicle and this was done when my car was still under warranty, but it was not brought to our attention that it existed until this year after the car's warranty was up. 2 seal kits, air springs and the struts!

NHTSA ODI 11714264

I had the 25v-274 recall serviced at my GM Dealer and was never provide with any paperwork on the extended warranty that was part of the recall. as you can image, not having anything in writing is a big risk as these engines have been catastrophically failing. GM was supposed to provide a extended warranty and service manual update.

NHTSA ODI 11713956

The engine has started using large quantities of oil. Not dripping oil, burning oil. I have been doing oil consumption studies with GMC for months now. It burned 7 quarts in 5,000 miles. The dealership tells me it is not part of the current recall on others with the same engine, make and model. It is doing the same thing as what the recall is for and my VIN number should be added to GMC’s recall list and the motor replaced. It is a serious safety issue for me and my children,

NHTSA ODI 11713798

NHTSA Team, I am the current owner of a 2021 GMC Yukon Denali (VIN: [XXX] ) with the 6.2L L87 V8. At approximately 148,239 miles, I experienced a catastrophic lifter failure. My mechanic diagnosed a failed AFM lifter and metal contamination, requiring full engine replacement. This is documented under GM Case #XXX. CARFAX revealed that prior to my ownership, lifters were replaced twice (~10,469 miles and ~25,572 miles). The dealership I purchased from did not disclose these prior repairs, as they used an alternative vehicle history check. Only upon this third lifter failure did my mechanic identify this recurring defect. I submit this to NHTSA’s investigation into post-repair failures of the GM 6.2L engines. The pattern shows prior remedies were insufficient. Supporting documents (CARFAX, mechanic report) are available. Please advise if further details or inspection of the failed engine components are needed. Thanks, [XXX] [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11713397

I habe a 2021 Yukon Denali and i have had engine failure on the road. Lifter issues and rod issues. i have paid out of pocket to fix it because my truck wasnt part of the recall. But i had the first failure in November 2024. Second failure January 2026.

NHTSA ODI 11713181

Loss of power while driving, no warnings, no lights on dash, no unusual noises, and no codes. The Yukon just randomly went into neutral while driving 65 mph and "Press Start Again" popped up on the dash. I struggled to get the truck to the side of the road safely. After getting the truck into park it started back up, and I was able to make it the 3 miles home. I scheduled it to go into the dealership as it still is making no noises, and had no engine light or codes, about 2 miles from my house it shut off again while driving, only this time when it restarted it now has a ticking sound coming from the engine however no warning lights and no codes being displayed. I am reporting this as I believe it falls under the open investigation EA25007, although it clearly is the same failures others have experienced on models that were included in the recall 25V-274. I am also attempting to contact GM as my vehicle is no longer under the powertrain warranty that was not extended for the vehicles that were not included in the recall.

NHTSA ODI 11712076

Internal engine failure Car just shut off on expressway, putting the safety of my husband and child at risk. Waiting for a tow at 12:30 in the morning. Problem has been confirmed by dealer. No warning lamps or warnings signs prior to failure. Car just shut down and was not able to start again. Had to be towed!

NHTSA ODI 11711984

I have a 2021 GMC Yukon with 74,000 miles I was recently told I need a new transmission.I am am trying to understand why a car that is 5 years with all the services done by Lehman GMC in North Miami would need a new transmission they have been servicing this car and no one mention anything breaking down of need of repair until now. I spoke with the service manager Franklin and he stated to me another client had the same issue and he flush the transmission just like I am doing today and it only worked for a short time and afterwards he had to replace the transmission. I feel this is a problem with these models and GMC don't want to address it. they just want the customer to pay for the repairs. Now I spoke to the Manager and the salesman that sold me the car and nicely told me he was sorry and he could get us out of this into a 2026. Now why would I buy a new car if they cannot get the 2021 right. I have included my invoice below I feel some one should look into this I feel this is a recall matter and GMC is trying to pass the buck. Thank You [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11710688

I live in Alaska. It was -13f. We were out and about and when I tried to leave and back up, the vehicle would not go into reverse. If it hadn’t been for a passing motorist my daughter and I would have been stuck there overnight, in negative temps. I was able to drive it home, in limp mode. Come to find out, it is the valve body on the transmission. That in cold temps the valve body can fail. After some research I found that it is a KNOWN issue with these vehicles and there has even been a “Urgent-Distribute Immediately” Service Update regarding the problem. Urging dealerships to review the VIN’s they have in their possession for the issue. I had the vehicle towed to a shop, where they confirmed the problem was the transmission valve body. They were unable to perform the work as it takes a qualified technician to replace. So it got towed to the closest GMC dealership. They have had it for two weeks now. They confirmed that it is a known issue and there have been no recalls. But they did tell me I was “in luck” because they stock that item so we won’t have to wait for a part. Not only is it going to cost me $3500 to replace something that is a know issue with this vehicle, but it could have ended in tragedy if no one would have come along when we were stranded. I urge you to make this a recall on these vehicles.

NHTSA ODI 11710382

I was driving down the highway at normal speeds under normal conditions and the engine light came on and started flashing. By the time I could find a safe place to pull over I heard the engine knocking. Left my wife, two young kids and myself stuck in the middle of the road with traffic coming. Managed to get it out of the road before going to get my truck and trailer to tow it home. I assume this is due to the L87 recall but mine was built in 01/21 and the recall is said to cover 03/21 and up. We don’t really know what to do at this point being its my wife and kids only way to work and school.

NHTSA ODI 11710038

On [XXX] driving to Denver the 52,000 mile yukon started making a clicking sound when accelerating on the interstate. Traction control light came on as well as the check engine light. Low power was noticed and we immediately pulled over as it sounded like it was going to blow up. Towed the vehicle 145 miles where we bought it and the shop confirmed the lifters and 5th cylinder are the issue and that the cams could be damaged. Recommend replacing each side. The car is basically new and under the 60K drive train warranty but about 100 days past the 5 year mark. Terrible timing. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11709435

I was driving and a message popped up "Service Traction Control", then another message popped up "Forward Collision System Unavailable". Then the car started making this knocking sound and every time I would try and accelerate there would be a loud sound and almost a pulling stopping it from picking up much speed. I took the car into the dealer/repair shop and they said it was an issue with the lifters that had to be replaced and potentially an issue with the cam. They said this repair would cost upwards of $6,000 and I have never had this issue with the car before. This came out of nowhere and the car had not been showing any signs of this occurring before. This is a 2021 GMC Yukon and I drive my Wife and three sons in that car daily.

NHTSA ODI 11709048

On Christmas Day while driving on the highway, I noticed a ticking sound coming from the engine. Our 21 Yukon Denali just hit 85,000 miles. I first noticed the traction control light was became disabled and then the check engine light started flashing. The sound escalates when you step on the gas. It appears that the lifters and cams are damaged on the vehicle and had to be towed to a dealership were it currently waits to avoid further damage. I was advised by the dealership that this particular vehicle is not part of the engine, recall notice, but heard that they might be expanding vin numbers to the recall as more incidents occur. They did confirm that the lifters and Cam’s are the issue.The vehicle has had a great maintenance record and was just at the same dealership five weeks earlier for oil change.

NHTSA ODI 11708634

Driving the vehicle on the highway when I started to hear a ticking sound from the engine. After a few minutes, the check engine light came on and started flashing, traction control shut off and some system related to the rear end shut off. After inspection, it appears to have dropped a lifter.

NHTSA ODI 11707664

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

NHTSA ODI 11707247

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.

NHTSA ODI 11707007

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.

NHTSA ODI 11706440

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.

NHTSA ODI 11705802

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,

NHTSA ODI 11705356

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.

NHTSA ODI 11705091

At the time an oil change is needed, there is a warning light that says "low oil pressure and low oil." There also has been a "slipping" of the engine at around 60mph. GMC dealer states it is a torque converter. I am worried that the engine will fail or stall while driving The fuel pump control module has been replaced. Motor is not covered under the current motor recall and taking vehicle to transmission shop to have it checked as well

NHTSA ODI 11704618

Clicking/rubbing noise when turning slowly. Rear differential issue diagnosed by dealer.

NHTSA ODI 11704122

Engine failure

NHTSA ODI 11703867

I got 3 messages on the dash going off simultaneously 1. Service Traction Control System 2. Forward Collision System unavailable 3. Service ESC I could feel the truck bogging and shaking a little at this point Then soon after the check engine light was flashing and it was noticeably misfiring and rough idling. I pulled some codes at Oreillys and got back 1. P0300 misfire 2. P050D cold start rough idle

NHTSA ODI 11701140