2020 GMC YUKON Complaints

I had an incident in my 2020 GMC Yukon, where the forward collision crash alert went off and there was total loss of brakes. The brake pedal went to the floor. After the crash alert ended, the brakes returned. This happened on the highway and could have turned into a disastrous event. The dealership has been unable to diagnose or recreate this issue. They claim they did not find anything and the vehicle is safe to drive. I have turned off the collision detection system in the meantime. I feel strongly that this is a software issue that needs addressed. GM has replied that they support the dealership but if I want a second opinion I can go to another dealership for input.

My 2020 GMC Yukon XL Denali 6.2L with 59,000 miles developed a ticking noise and slight power loss diagnosed by three different garages as a "collapsed lifter" on #4 cylinder. It's one of the AFM/DoD cylinders that shuts down to save fuel. $8,000 repair estimate, or $12,000 if the failed lifter damaged the camshaft. All three garages said "we see a lot of these." Internet forums are loaded with lifter problems on this engine: specifically AFM/DoD lifters. Safety is not affected. Noise/diagnosis reproduced by three independent garages. Has not been inspected by mfg, police, or insurance rep. No warning lamps or messages, no ODB2 "codes" found by garages. Seven months ago the water pump exploded on Interstate 70, putting us at serious risk. Now this lifter trouble at 59,000 miles. Both should have been covered by the 60,000 mile powertrain warranty, but I'm beyond the 5-year limit.

Complete engine failure while driving on I25 in New Mexico, lost all power was able to roll into a airport parking lot. If I had not been close to the off ramp it could have been catastrophic with the truck traffic on the Interstate. The vehicle has completed all of its normal maintenance on time, and as of January 30, 2026 had a complete review from GMC that everything was in great shape including the engine. There was never a warning light, a maintenance message or any other indication.

MISFIRE ON #6 CYLINDER. DIAGNOSIS REVEALED THE INTAKE VALVE IS NOT OPENING DUE TO COLLAPSED VALVE LIFTER. No message prior to engine light coming on and car shaking after driving back from the store (speed less than 45 MPH).

I purchased my 2020 Yukon Denali on July 8, 2024 from Classic Buick GMC in Painesville, Ohio. The check engine light started going on and off a few months after purchasing the vehicle. When I called a mechanic he stated that I should wait until the light is on and then bring in the vehicle. In early May 2025, I took my vehicle to Mike’s Automotive in Middlefield, Ohio after the check engine light began coming on during extended drives (approximately five hours or more). The shop ran a diagnostic scan and advised that the oil pump needed to be replaced. Seeking another opinion, on May 14, 2025, I brought my vehicle to Classic Buick GMC Service, the dealership where I purchased my GMC Yukon. After diagnosing the vehicle, they advised that the check engine light was related to an Engine Oil Pressure Control Solenoid stuck in the off position (P06DD). This fix would cost $3,584. This fix would require the oil pump to be replaced as indicated by the previous repair shop. On May 29, 2025, I took the vehicle to Avenue Auto Clinic in Painesville, OH, where the oil pressure valve and sensors were replaced. The mechanic also advised that I change the oil every 3,000 miles, use OEM oil filters, and thicker oil. He also advised me to check the oil every 1,000 oil and add as needed. I do have to add oil approximately every 1,500 miles and I change the oil every 3,000 miles. I am concerned that my vehicle has the same engine-related defect as the Yukon engines currently under recall. Multiple mechanics have informed me that my vehicle is equipped with the same engine as those affected by the recall. I am requesting that my vehicle be added to the recall. Yes, my vehicle is available for inspection.

Transmission started slipping a little and then literally stopped working all with in an hour. And was doa in the parking lot.

My 10 speed transmission on my 2020 Yukon XL Denali experienced a total failure. The vehicle will not move under its own power. General Motors has ZERO information on when a replacement Transmission will be available. Some info online shows it could be months. I am told that one dealership out of Eden Prairie, MN has over 40 on back order and some since August 2025. They claim the issue stems from a valve body. Their communication has been terrible and no one within GM that I have spoken to has any information on what is being done. This is completely unacceptable and I believe it is part of a larger issue. They are making it seem like it’s not important and that needs to change.

The contact owns a 2020 GMC Yukon. The contact stated that while driving at an undisclosed speed, the check engine warning light was illuminated. The vehicle was taken to the residence, the contact exited the vehicle and discovered white smoke coming from the exhaust and started to smell coolant and then discovered that the coolant level was low. The contact added coolant, and the check engine warning light was no longer illuminated. The contact’s husband and son, who were knowledgeable about vehicles, had self-diagnosed the vehicle and determined that the head gasket or the lifters might need to be replaced. The contact stated that the failure had occurred on several occasions and the contact consistently added coolant; however, the check engine warning light was illuminated every 300 miles once again. The contact researched and was made aware of an unknown NHTSA Campaign Number; however, the VIN was not included. The vehicle was taken to an independent mechanic, where it was diagnosed and determined that there was an unknown internal issue with the engine that was possibly associated with coolant leaking into the engine. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 52,000.

I was traveling along i80 and suddenly the vehicle shutdown. I put the transmission in Neutral and coasted to a stop. Once stopped, I check It would not start or even turnover at that point. I still had all electrical services and such. The vehicle. I was stranded on i80. Then had to be towed to the nearest GM Dealer in Evanston Wyoming. Heritage Chevrolet GMC. It was left there for diagnosis where their technician, several days later diagnosed it with a bad engine. There was no warning or check engine light that appeared. I even have a picture from a little while earlier while driving earlier that morning. It took it because I was surprised it was getting 28mpg in v8 mode. but I am glad I had that photo to show no diagnostic lights were on.

Knocking noise from engine-no check engine light initially. Next time it was started knocking was still present and the check engine light was on. Contacted Champion Chevrolet in LaGrange KY. Dealership diagnosed problem (Code P0308 - Cylinder 8 misfire). Compression test on Cylinder 8 failed. Removed valve cover and confirmed loud tick in the rocker shaft and worn camshaft lobes. Was told I would need a new engine and that repairing the existing engine was not cost effective. So, $22,722.14 later, i have a new engine in my 2020 GMC Yukon and have the original engine (core charge) in my shop in case it is needed for evaluation to help determine if the GM recall should be expanded to 2020 model year (and others not covered by the current recall).