2015 GMC Yukon: engine failure

Filed Sep 22, 2026 · Engine · WA

The vehicle developed a recurring cylinder #4 misfire with a flashing check-engine light, rough running, and reduced performance. Diagnostic code P0304 repeatedly returned. Replacing the #4 spark plug temporarily restored normal operation, but the misfire returned after a few hundred miles. The #4 plug was wet/oily, and fresh oil was found pooled in the #4 intake port while the other ports were dry. All eight spark plugs, ignition coils, and plug wires were replaced, along with the #4 fuel injector and both #4 valve-stem seals, but the misfire persisted. A valvetrain/lifter tick later became audible near 3,000 RPM. The failure has now been confirmed as a valvetrain failure that severely damaged/destroyed cylinder #4 and requires complete engine replacement. The vehicle is available for inspection upon request. This defect creates a serious risk of severe misfire, loss of engine performance, or complete engine failure while driving.

Filed May 23, 2026 · Engine, Fuel system · OR

While traveling at highway speeds on Interstate 5 in Oregon, my 2015 GMC Yukon Denali experienced a sudden, catastrophic engine failure with zero advance warning. The vehicle instantly lost almost all propulsion and power while surrounded by high-speed traffic, creating an immediate and severe safety hazard on a major interstate. The engine began making a loud, severe knocking noise, and I was forced to navigate across lanes without adequate power to reach the shoulder. The vehicle was towed and inspected by Point S in Creswell, OR, where diagnostics confirmed a P0300 random/multiple cylinder misfire, with cylinder 4 specifically misfiring. Using a stethoscope and scanner to isolate the failure, technicians confirmed a catastrophic rod knock failure at the bottom end of the engine. The vehicle was then taken to Sam’s Automotive Service, where a complete engine replacement was executed at a total out-of-pocket cost of $16,000. General Motors has a well-documented history of internal engine failures on these 6.2L V8 platforms, yet they have failed to issue a safety recall for vehicles experiencing this sudden, dangerous highway power loss.

Filed Jul 16, 2025 · Engine, Transmission · TX

Driving down the expressway at 65MPH, and the Vehicle completely stops, almost causing a collision. After researching the problem at the GMC Dealer, it appears that the entire engine has internally failed. Apparently it was a Complete Engine Failure.

Filed May 5, 2025 · Engine · MS

Started my 2015 Yukon XL, drove approximately 6 miles to get gas and was to head out onto the highway. After gassing up and starting engine it began to idle very rough with a shake going on and ticking noise. No previous signs of any issues. Slowly drove back to my house at 20 miles an hour and called Mandal GMC dealership. They suggested having it towed to them for inspection. Upon inspection they said the AFM/DOD #1 exhaust lifter was bad and needed replaced. They replaced all of Bank one lifters and said their was no damage to camshaft. Drove it that night after repairing it and everything seemed fine. They called the next morning and said when they started it up the ticking was back again. They then supposedly took off head cover and inspected the camshaft again and said it was damaged and I would need a new engine to the tune of $18,000.00. I purchase it in 2021 from them use and paid $33,000.00 and now still owe even more than the engine repair. I said it would cost more than the vehicle was worth and they had done $4,000.00 of repair that didn’t even get the issue fixed. I am a senior on Social Security and can not afford to continue to pay 20,000.00 for the loan and then another $18,000.00 for a faulty engine design that caused the problem in the first place. May have to join the thousands of others in the class action to get GM to not put out such untrustworthy engineering. Now $37,000.00 piece of Yard Sculpture !! The morning that it occurred was the first sign of flashing engine warning on dash.

Filed Feb 2, 2025 · Engine · FL

2015 6.2l yukon lifter failure oil changed 2000 miles ago and lifter failed and possible cam damage due to AFM lifter failure vehicle has 115,000 Miles and Gm knows about these lifter failures that can blow engines and cause serious accidents due to rapid loss of power and controls that GM already knew paid alot of money as a certified pre- owned and failed to disclose lifter defects to their customers now at shop for complete inspection and now needs possible new engine when all service requirements were met now looking at thousands of dollars for repairs if known i would have not bought the vehicle. And deceiving GM customers , currently waiting for diagnostic in writing but the courts approved recall already from same issues on 2019 and newer but same lifters are in the same 2015 AFM system

Filed Apr 24, 2023 · Engine, Transmission · MA

Vehicle had lifter and valve noise Lifters and valves became stuck due to Active Fuel Management system failure Transmission shifted poorly due to this condition. Resulting in engine failure and engine replacement at my expense Total cost $12,000

Filed Apr 22, 2019 · Electrical, Steering · CA

Tl* the contact owns a 2015 gmc yukon. Shortly after the contact purchased the vehicle, there was an electrical failure and the radio failed to function. The dealer (penske buick gmc of cerritos, 17720 crusader ave, cerritos, ca 90703, (877) 886-6265) replaced the radio with a warranty; however, the failure continued. Also, the vent controls failed for the air conditioner and heater. While making a left turn and a u turn, the steering wheel seized several times. The dealer indicated that they serviced the vehicle per the federal safety agency campaign number: 18v586000 (steering) and was aware that the recall remedy failed. The condition progressed to the point that the vehicle began to stall. The vehicle was not repaired. The manufacturer was notified of the multiple failures. The failure mileage was not available.

Filed Apr 2, 2019 · Engine · AZ

2015 gmc yukon. Consumer writes in regards to engine failure while driving. *ld

Filed Apr 20, 2015 · Engine, Seats · 22,500 miles · TX

I have a 2015 yukon denali and I was driving 65 on the highway and the engine shut down completely. A warning message said engine power failure. I had 4 cars and an 18 wheeler behind me at the time. I managed to put the vehicle in neutral and coast to the side of the road onto a median. It was towed to the dealership where they started trying say it might have been bad gas. Then I was told I cracked valve and they already had one other just like this, then 1 day later after a tech level 2 and a shop forum looked at it, and a conversation with a gm pac rep, gm approved a complete engine replacement! I was shocked. I've had the same 4-wheel drive issues everyone else has. I've also had A/C problems, steer wheel popping noises, sunroof loud wind noises. My seat shifts when I drive it. The A/C seats don't cool properly, which I found out when they put me in a loaner yukon that worked fine. The speedometer gauge also didn't work for 2 days, which I have a picture of and received a warning ticket for when I was pulled over by an officer not knowing what speed I was going. I passenger step guard doesn't always retract properly. My unit was purchase may 2014 and was one of the first 4 x 4 units that was produced and has had constant problems. Gm keeps denying a buyback, then no trade assistance, then now has offered an extended warranty. This particular vehicle I have is not safe for my family to be riding in. I can't trade it in or sell it to anyone else knowing the problems it has. The dealer won't even take it because they know the problem that they are dealing with.