2023 GMC Yukon

I have a 2023 GMC Yukon SLT. The OnStar/telematics system stopped working. The blue OnStar button does not function, and the vehicle no longer communicates with the myGMC app, resulting in the loss of OnStar and connected services. A GMC dealership diagnosed a failed OnStar/telematics module and advised that replacement will cost approximately $1,200. This creates a safety concern because OnStar provides emergency services, including Automatic Crash Response and the ability to request emergency assistance from inside the vehicle. A module failure could leave an occupant without access to these services when they are needed most. I am also concerned that OnStar and telematics failures appear to be reported by owners of multiple GM vehicles, suggesting this may not be an isolated failure. I am requesting that this issue and similar complaints be investigated to determine whether there is a broader defect requiring a recall, warranty extension, service campaign, or other corrective action.

On May 8th of 2026 my 2023 GMC Yukon with approximately 42,900 miles experienced an complete failure of the 6.2L engine requiring replacement. The engine failure occurred despite the engine having recently undergone inspection and special oil being used related to NHTSA 25V274 / GM N252494000 recall. When the engine failed, the vehicle could not be towed or pushed out of the flow of traffic because the computer will not allow the vehicle to be shifted into neutral, only showing "Conditions not correct for shift" in the instrument cluster. This sudden and unexpected loss of engine power combined with the inability to remove the vehicle from the lane of traffic creates a dangerous situation.

I am filing this complaint regarding a catastrophic engine failure in my 2023 GMC Yukon Denali. I purchased the vehicle on January 30, 2026. Shortly after purchasing it, the vehicle suffered a catastrophic engine failure. The failure was severe enough that the engine had to be completely replaced. My vehicle was out of service for approximately 38 days as a result. This was not a minor mechanical issue or routine repair. It was a catastrophic failure of a major component in a relatively new vehicle. I am extremely concerned about the safety implications of an engine failing without warning. An unexpected engine failure can result in a sudden loss of power and the inability to safely accelerate or maneuver, particularly when traveling at highway speeds or in traffic. The fact that the engine required complete replacement raises serious concerns regarding the reliability and safety of this engine and whether other GMC and Chevrolet vehicles equipped with the same or related engine may be experiencing similar failures. I am requesting that NHTSA formally document this catastrophic engine failure and investigate whether it is part of a broader pattern of engine failures involving these GM vehicles. I have documentation showing the engine failure, dealership diagnosis, complete engine replacement, repair history, and the approximately 38 days the vehicle was out of service. I can provide these records upon request.

The check-engine light first appeared at approximately 42,000 miles. I dropped the vehicle off at the dealership on August 22 and picked it up on September 1. Within TWO MILES of leaving the dealership, the check-engine light came right back on. The dealership initially diagnosed the problem as a lifter and wiring-harness failure. They later determined that the #7 oil-lifter solenoid had an internal short, and the wiring harness was replaced because of damage related to that short. What I still don’t have is an answer to the most important question: What actually caused the failure? Based on everything I’ve read about the problems surrounding GM’s 6.2L engines, I’m concerned this is only the beginning. These are extremely expensive vehicles—with monthly payments that can rival a mortgage—and owners shouldn’t have to wonder whether the engine is going to become an ongoing problem at 42,000 miles. Extending the warranty is helpful, but it doesn’t address the underlying issue or restore confidence in the vehicle. If these 6.2L engines have a known systemic defect, GM should be required to provide a permanent solution—whether that means replacing the affected engines or offering owners a fair buyback. Consumers paid a premium price. They should be able to expect a premium vehicle that is dependable.

1.Description of the Incident: On 6/28/26, while driving my 2023 GMC Yukon Denali at approximately 70 miles per hour with cruise control engaged, I attempted to take an exit. As I approached the exit, the vehicle’s display indicated that it was not in gear, despite being in motion. This malfunction occurred in heavy traffic, and I narrowly avoided a collision with a semi-truck as I maneuvered towards the shoulder of the road. Once safely on the shoulder, I attempted to shift the vehicle into Drive and Park, but the system reported that the application was not available, rendering the vehicle inoperable. After several unsuccessful attempts to restart the vehicle, I lost all power, leading me to suspect a battery or alternator issue. 2. Component/System Failure: The component that failed is the engine, which was subsequently diagnosed as having failed by the dealership. The failed engine is available for inspection upon request. 3. Safety Risks: This incident posed significant safety risks, including: •Risk of Collision: The sudden loss of power at high speed nearly resulted in a collision with a semi-truck and other vehicles, putting my life and the lives of others at risk. •Stranded in Dangerous Conditions: Being stranded on the side of the road in 100°F weather further exacerbated the situation, creating a potential health hazard. 4. Confirmation of the Problem: The problem was confirmed by the dealership that serviced my vehicle. They conducted a thorough inspection and determined that the engine had failed. Independent verification of the engine failure is available upon request. 5. Inspections by Authorities: The vehicle has been inspected by the dealership; however, it has not been inspected by police or insurance representatives. Documentation from the dealership regarding the inspection and engine replacement is available. 6. Warning Signs Prior to Failure: Prior to this, there were no warning lamps, messages, or symptoms indicating a problem prior.

L87 recall was completed on 10/22/2025. On August 8th 2026 the engine developed a loud knock. It was taken to the dealership on 8/31/2026 after inspection it was determined that the engine had failed and needed to be replaced. There was no warning lamps that indicated there was an issue with the engine. The vehicle was still driveable when it was taken to the dealership. If the engine had completely failed while on the highway it could have caused a major incident.

2023 Yukon Denali, 6.2 Engine. Owner complied with first GM recall and the engine passed inspection. 8/16/26 Engine started making a knocking sound. 8/17/26 Yukon was taken to the dealership and diagnosed as complete engine failure. There were no warnings indicated on the dash. Yukon is currently still at the Dealership with no repair date issued. Today is 9/3/26. I have contacted GM regarding a possible buy-back. GM said they would email in 24-48 hours. I have not heard from GM and it is now 72 hours since my initial phone call.

My vehicle was with ANCIRA GMC Boerne for approximately three weeks where they replaced the transmission control system/module, the centralized OnStar module, and diagnosed both rear screens for replacement. Approximately one month after getting it back, at only 49,800 miles, I experienced a complete loss of propulsion. The vehicle shut down while I was driving. Given the recent transmission repair and the fact that this failure occurred while the vehicle was in motion, I no longer have confidence in the safety or reliability of this vehicle. I have young children riding in this vehicle daily and I’m not comfortable accepting another repair and simply being told it’s safe to drive.

The contact owns a 2023 GMC Yukon. The contact stated that while driving 65 MPH and depressing the accelerator pedal, the transmission shifted into neutral. The contact pulled over to the right side of the road and attempted to shift into drive; however, the failure persisted, and the vehicle lost power. No warning light was illuminated. The contact stated that the vehicle was towed to the dealer and was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was serviced under NHTSA Campaign Number: 25V274000 (ENGINE AND ENGINE COOLING); by the owner of the vehicle, but the remedy failed to fix the vehicle. The contact stated that the failure had occurred after the recall repair. The manufacturer was notified of the failure and informed the dealer to replace the engine. The engine was replaced, and the vehicle was repaired. The failure mileage was 56,600.

I have a 2023 GMC Yukon that has been to the dealership 3 times in a weeks time, and as of today, 8/31/26 will be the fouth time. On 2 occasions, the SUV has entered Limp Mode while driving. I had the SUV towed for the first limp mode, and the dealer claimed it needed recalibration modules. I picked up the car and drove home eight miles, and the check engine light came on. I returned the next day for readings and TCM P0700, P1789, U0101, U220F. The dealer's solution was to recalibrate the gateway module this time. I drove the car about 20-ish miles, and at highway speeds on the freeway, I got limp mode again. Off to the dealership, having the SUV towed again. The dealership has claimed the electrionic car codes clear themselves and because of that they can't re-create the codes to find a solution. I am scared to drive my SUV, I do not feel safe in it let alone my children.