2021 GMC Yukon: check engine light

Filed Oct 26, 2026 · Engine · AR

As I was driving down the road at 60mph, no dash lights or warnings were present. All of a sudden, my 2021 yukon lost all power and I nearly crashed as I was in heavy, fast paced traffic. I got to the side of the road, and it was at this time the engine light came on. Car died and wouldnt start back up.

Filed Oct 20, 2026 · Engine, Transmission · PA

VEHICLE: 2021 GMC Yukon, 5.3L V8 (L84). VIN: [XXX]. Mileage at failure: approximately 88,000. Component: Engine. INCIDENT DATE: XXX While I was driving on a highway, the engine began to misfire and I heard a ticking noise. The check engine light then began flashing, indicating a severe misfire. I pulled off the highway immediately to a rest area. The vehicle was towed to a GMC dealer. The dealer's diagnosis suspected failed valve lifters, and the repair orders call for a misfire diagnosis with the Bank 1 cylinder head removed, and replacement of the camshaft, lifters, and related parts. This failure caused sudden loss of engine performance at highway speed. The engine began smoking. My family and I were in the vehicle, and we were fortunate there was a safe place to stop. I believe this is a known defect. GM Service Bulletin PIP5776, "Misfire Due to Collapsed Lifter," covers 2021 GMC Yukons with the 5.3L L84 engine. It describes a misfire with a bent pushrod leading to a collapsed lifter or a lifter that comes apart, and it attributes the cause to an internal lifter concern. Many other owners of GM V8 trucks and SUVs have reported the same failure, and a class action over the AFM/DFM lifters has been pending against GM in federal court in [XXX] since 2021. I bought this vehicle new and have maintained it. This is the second time this vehicle has left my family stranded on a highway. In 2024, a separate known issue left us, including three children under [XXX], on the side of a major highway about 7 hours from home. GM repaired that issue. For the current failure, GM has not agreed to cover the repair. It has offered $5,951.39 toward an engine replacement, which would leave me responsible for $13,886.59 plus teardown labor. I am filing this complaint so the federal safety agency is aware of this failure, which can cause sudden loss of power on the highway. GM case number: XXX. Dealer: Fred Beans Buick GMC, [XXX]. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Oct 6, 2026 · Engine · TX

While driving on the highway with my child in the car, the car suddenly began shaking and warning lights to check the power train came on the dash. There was also a loss of power in acceleration. Other error codes (303) also appeared with the check engine light also coming in. Upon checking the code later once home, it indicated there was an issue with the lifters. The car was then towed to the dealership where it was confirmed there are issues with both the lifters and the cam shaft and both need to be replaced.

Filed Sep 21, 2026 · Fuel system · PA

My 2021 GMC Yukon has approximately 36,900 miles. On September 12, 2026, the vehicle was at an authorized GMC dealership and passed a state safety inspection. On September 19, 2026, the check-engine warning light illuminated and I returned to the dealership. The dealer performed diagnostic testing and told me the fuel pump pressure was approximately 400 PSI when it should be approximately 700 PSI. I was told the fuel pump needs to be replaced. The vehicle is currently at the dealership awaiting the replacement part: Fuel pump I was not aware of a fuel-pump failure before the warning light appeared. I am particularly concerned because this failure occurred at only approximately 36,900 miles. GM previously recalled 3,386 2021 GMC Yukons under the federal safety agency Campaign 21V‑739/GM Recall N212332040 for a fuel-pump power-control-module defect that can cause the fuel pump to fail or operate intermittently, interrupt fuel flow and potentially cause the engine to stall. My 2021 Yukon is not included in that recall and currently shows no unrepaired recalls associated with my VIN. I believe this represents a potential safety concern because inadequate fuel delivery or a fuel-system failure while driving could cause reduced engine power or an unexpected stall, increasing the risk of a crash. Given the low mileage, the dealer-confirmed fuel-pressure problem, and the existing fuel-pump-related safety recall affecting other 2021 Yukons, I am concerned that my vehicle may have the same or a related defect despite not being included in the recalled population. I believe the federal safety agency should evaluate whether additional 2021 Yukons should be included in a safety investigation or recall. I am paying out of pocket to have the fuel pump replaced and am filing this complaint to document the failure.A fuel-pump failure at only 36,900 miles is extremely concerning. I ask the federal safety agency to determine whether my vehicle has the same or a related defect and whether the existing recall population should be expanded.

Filed Sep 15, 2026 · Engine · 95,000 miles · MO

The contact owns a 2021 GMC Yukon. The contact stated that while his wife was driving 65 MPH on the highway at higher speeds, the vehicle shuddered abnormally. The check engine, ECU, and traction control warning lights illuminated, and the message "Shut off Vehicle as soon as Possible" was displayed. The contact's wife pulled over to the shoulder of the road, and the vehicle was towed to an independent mechanic for diagnosis. The mechanic retrieved dDTCs: P0307 and P050D, indicating a failed roller lifter, valve spring, and valve roller lifters. The vehicle was later towed to a local dealer, where the dealer diagnosed that the lifters had failed and needed to be replaced. The manufacturer was notified of the failure. The failure mileage was approximately 95,000.

Filed Sep 3, 2026 · Engine · MS

My 2021 GMC Yukon began experiencing severe engine problems, including shaking/rough running, a noticeable ticking/knocking noise from the engine, and a flashing check-engine light. The vehicle also displayed Service ESC and traction control warnings and exhibited symptoms of an engine misfire. I took the vehicle to a dealership for evaluation. I was advised that the problem may involve failed lifters and that the vehicle could be out of service for several weeks for repairs. I was also advised that the repair could be very costly. At this time, I have not been given a final diagnosis, so the exact internal engine component responsible for the failure is UNKNOWN. I am concerned that the condition presents a safety risk because the engine is running extremely rough and the check-engine light is flashing. I am afraid the engine could lose power or fail while the vehicle is being driven, potentially putting me, my passengers, and other motorists at risk. I have also become aware of the federal safety agency's investigation involving failures of the 6.2-liter L87 V8 engine in GM vehicles, including the GMC Yukon, as well as reports of engine failures occurring after certain repairs or recall remedies. This has increased my concern about whether repairing or replacing individual engine components will permanently resolve the problem. I am submitting this complaint so that my vehicle's symptoms, dealer evaluation, and potential engine failure are documented. The vehicle and affected components are available for inspection upon request. The dealership has evaluated the vehicle, but a final determination of the exact cause has not yet been provided.

Filed Aug 29, 2026 · Engine, Fuel system · OH

Took car in to have it checked for recall on engine and have oil changed to new standards with WD40 was told the engine and car was fine “just use this new oil” A MONTH later was driving and engine would not shift come to find out our transmission was going out it was replaced thanks to our extended warranty (even tho it only had 98,000 miles on it) a week after a fuel pump was out and we had to pay to replace it. There were never check engine signs and no signs of the car having failure truly it ran great until the new oil.

Filed Aug 18, 2026 · Brakes, Electrical · TX

As I was driving, the vehicle's air conditioning suddenly began blowing warm/hot air. Moments later, the check engine light and all electronic service stability lights illuminated on the dashboard. Simultaneously, the vehicle suffered a complete loss of electronic brake assist, resulting in an extremely hard brake pedal and a severe reduction in braking power. The vehicle also displayed a "No Drive Mode Available" message. Third-party diagnostic scanning revealed network power codes U3018, U3505, P00FF, and P0700, indicating a total loss of power to the Body Control Module (BCM). This is the second life-threatening incident with this vehicle I have experienced following a previous highway engine stall due to engine recall. The vehicle was towed to a GM dealership for diagnostic and emergency electrical repairs.

Filed Aug 12, 2026 · Engine · TN

The vehicle was driving down the highway when the oil pressure instantly dropped. 2021 Yukon’s safety system advised pulling over immediately, engine warning light appeared, and vehicle turned off. No prior indications of an issue. It would not restart and was towed to mechanic. Independent service center diagnosed issue as a broken crank shaft. It now needs the engine replaced and does not fall under the recall vin numbers acknowledged for the same issue.

Filed Aug 11, 2026 · Acceleration, Brakes · TX

On July 28, 2026, while traveling on vacation with my family, our vehicle experienced a catastrophic engine failure. There were warning lights displayed for 30 seconds prior to the engine failure. On July 23, 2026, one day before taking the vehicle to the dealership, the following warning indicators appeared on the dashboard and then disappeared: “Service ESC,” “Service Traction Control,” and a flashing engine light. We took the vehicle to the dealership on July 24, 2026, because we wanted to be proactive and ensure that the vehicle was safe to operate. The dealership inspected the vehicle but reported that no diagnostic trouble codes were identified and no issue was found. We picked the vehicle up from the dealership on the evening of July 27, 2026. On July 28, 2026, while traveling on the highway approximately 2.5 hours from home, the same warning messages appeared on the dashboard again. Because we were traveling at highway speeds and vehicle speed management was becoming an issue, I immediately exited the highway and stopped in a parking area. I placed the vehicle in park, at which point the engine began idling extremely rough. I could feel the vehicle shaking while sitting in the driver's seat. I exited the vehicle to open the hood, but before I was able to do so, I noticed gray smoke coming from the exhaust. We located a GMC dealership approximately two miles away. Because of the vehicle's condition, we drove there slowly on the frontage road at approximately 15 mph and dropped the vehicle off for diagnostic inspection. The GMC dealership subsequently diagnosed the vehicle with catastrophic engine failure and recommended that the engine be replaced. The vehicle remains at the dealership and is available for inspection.We made a reasonable effort to have the vehicle inspected before our trip because we were concerned about the warning indicators and wanted to ensure that the vehicle was safe to travel.

Filed Jul 31, 2026 · Engine · 100,000 miles · IA

The contact owns a 2021 GMC Yukon. The contact stated that while driving approximately 50 MPH, the check engine warning light started blinking and the vehicle started shaking violently. The vehicle was pulled over to the side of the road and turned off. The vehicle was then towed to a dealer where it was diagnosed with a stuck lifter. The contact was informed that the lifters needed to be replaced. The vehicle was not repaired. The contact believed that the failure was associated with an undisclosed recall number. The manufacturer was notified of the failure. The failure mileage was approximately 100,000.

Filed Jul 25, 2026 · Engine · AR

Knocking sound and flashing engine light came on. When brought to dealership it was determined that lower bearing failure took place requiring full engine replacement. '