Which parts fail
Components named in complaints (automatic emergency braking, adaptive cruise, lane keeping, backup camera).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2021 GMC Yukon owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact rented a 2021 GMC Yukon. The contact was driving at 75mph, the contact stated they felt the steering wheel was moving independently causing the vehicle to veer in the opposite direction. Both hands were required in order to control the steering wheel. The contact attempted to avoid a large puddle, the vehicle independently veered to the right causing a crash with a curb and crossed an exit ramp which caused the vehicle to crash then into an embankment and into a ditch. This caused damage to the front passenger side tire of the vehicle. The side air bags did deploy but not the front driver or passenger side airbag did not deploy. No warning lights illuminated from the vehicle. The medical treatment was at the scene in which they checked the contact father in- law and their baby and took them to the hospital by ambulance with the contact's wife who was also in the vehicle. …
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. …
The contact owns a 2021 GMC Yukon. The contact stated that while driving at various speeds, the vehicle shuddered abnormally with blue smoke coming from the exhaust, with the message "Lane Departure Assist" displayed. The check engine and stabili-trak warning lights were illuminated. The vehicle was taken to a local service center, where it was diagnosed with cylinder #1 misfire. The local dealer was contacted. The vehicle was not diagnosed or repaired. Upon further investigation, the contact related the failure to the GMC Service Bulletin:15-06-01-002L. The manufacturer was made aware of the failure. The failure mileage was approximately 110,000.
The contact owns a 2021 GMC Yukon. The contact stated that while driving at various speeds, the Forward Collision Avoidance system erroneously activated, causing the vehicle to suddenly slow down. The vehicle was taken to the local dealer who serviced the Forward Collision Avoidance system camera and sensors. No further information was available. Additionally, while driving at highway speeds, there was a knocking sound coming from the engine compartment, and the seat restraint failure message was displayed. The cause of the failure was not yet determined. The manufacturer was notified of the failure. The failure mileage was 20,000.
I was involved in a vehicle accident on 10/6/2021 where my vehicle was stuck by an uninsured motorist driving recklessly on the interstate causing a total of 4 car collision. My vehicle was a a 2021 GMC YUKON SLT SUV, in which I was struck on rear drivers side quarter panel and again by another vehicle in the front bumper by another vehicle that struck in the rear bumper by the reckless driver. With my vehicle being struck by two vehicles I was shocked to learn the Onstar safety security features did not detect or contact me regarding the accident. It wasn't until the wrecker driver arrived to pull my vehicle onto the tow truck that I received a diagnosis notification email from o star about my antilock braking system. …
Upon cold start vehicle rattles when idling down and growling noise when accelerating upon left or right turns. Also, has constant vibrations with sound of metal rattling at speeds above 30 mph. Forward collision light on without a significant amount of mileage on vehicle. I have taken my vehicle to dealership at least 5 times referencing the vibrations. Growling noise was heard by service advisor last visit October 2024, and he stated it probably were the tires. I advised him that brand new tires were put on vehicle, April 18th 2024, rear vibration has never stopped from time of purchase. I have asked dealership to check drivetrain as it is a know issue for 21 Yukon Denali. Vehicle has not received recall but was manufactured at Arlington plant where the parts of the drive shaft was not properly heated and differential is known for issue upon cold start. …
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.
While driving vehicle on 11/08/2025, vehicle made a popping noise and loss power. We were out of town and had to pay out of pocket to have vehicle towed to a dealership and hour away from our home. Dealership diagnosed issue with engine failure due to lifter fell and caused damage to cam shaft and bore. I will be without a vehicle for an additional 2 to 4 weeks waiting on a back ordered engine from GM, and continue making payments on vehicle as well. This issue seems to be an ongoing problem that GM is ignoring.......GM should compensate towing, car rental, and repair/ replacement charges due to failure.
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.
The component that failed was the Camshaft and Lifters in the Engine - My safety and others was put at risk because while going 45mph, I suddenly lost forward moving power and couldn't go faster than 35 - braking power was sketchy and only responsive when pumped. - I received the following errors on my dash "Service ESC" "Service Traction Control", Reduced Acceleration Drive with Care", "Forward Collision System Unavailable", "Service Emission System" the vehicle would shudder violently- this problem has been confirmed and corrected at a huge expense (see bill) -
Collision Avoidance complaints in other Yukon years
Frequently asked questions
How common are collision avoidance problems on the 2021 GMC Yukon?
NHTSA has 23 complaints about the driver assistance of the 2021 GMC Yukon, 7% of the model year's 341 complaints. The component named most often is warnings (11 mentions).
Is there a recall for 2021 GMC Yukon collision avoidance problems?
No. NHTSA lists no driver assistance recall for the 2021 GMC Yukon, though it has 13 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2021 GMC Yukon collision avoidance problems start?
Half of the complaints with a recorded mileage happened before about 16,000 miles, and 80% before 25,000 miles.
Is it dangerous?
Owners linked 3 crashes, 0 fires and 5 injuries to driver assistance problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.