2023 GMC Sierra 1500

A GM warranty engine replacement was performed at Heyward Allen GMC in [XXX] on XXX at 70,415 miles. We purchase the vehicle on XXX with 73,904 miles and after driving for a month started having multiple malfunction indicator lights displaying, and experienced a no start condition. We took the vehicle to the Don Ledford GMC dealer in [XXX], and they performed a high level inspection. They found missing mounting brackets, loose wiring harness wires, broken and missing bolts. Issues all related to an engine replacement procedure. Deeming the vehicle unsafe to operate. The origin dealer that was paid through GMC to replace the engine is now refusing any responsibility for resolving these issues. Technicians have video evidence of the workmanship issues, documenting the sub- par repair work performed during the engine change. The vehicle now sits at the Don Ledford GMC dealer awaiting an estimated $4400 repair, before the vehicle is safe to operate on the road. The vehicle has been at the Don ledford dealer since XXX, and is still there today, XXX. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

1 - The Engine or something electrical, possibly the ECM, failed or malfunctioned, and yes, it is available for inspection. 2 - The vehicle lost power, reduced speed, was hard to steer, and I couldn't put the hazard lights on; this occurred twice while driving on the highway, once I was driving at approx 75 mph. The results could have been catastrophic not only to myself but to others on the road. These two events are not the only times the truck did this. 3 - No. 4 - No. I filed a claim with GM, but it has been approximately a month, and I've received no updates. 5 - No. Further: This event has occurred 6 times. I've taken it to the dealership three. They cannot duplicate the issue, so no repairs have been done. Apparently, approximately 100 codes come up, but they cannot diagnose the problem.

13 unresolved problem codes relating to hard engine starting,rough engine running,vehicle initiating safe mode operation, upon a highway trip. P0016 engine code detected and Onstar messaged for immediate service. No resolution at dealership , after resetting codes an additional 9 are active / pending at 2nd dealership visit. Abnormal engine operation since , dealership advises a hard failure has to occur before a resolution can be instituted. Similar advice from GMC direct phone call in help line.

My 2023 GNC Sierra 1500 has experienced a recurring electrical and safety-related malfunction on multiple occasions while driving. The dashboard and warning lights intermittently flash on, and off and numerous warning messages appear simultaneously. During previous occurrences, warnings included power steering service, safety restraint system, check engine and transmission related messages, including a message instructing me to pull over and shut the vehicle off. During one occurrence, the electric power steering assist stopped working while I was driving. The vehicle was taken to an authorized GMC dealership multiple times while under the factory warranty. The dealer replaced the Brake System Control Module and performed vehicle-wide software/programming updates. When the problem continued, the dealer contacted GM Technical Assistance. The Dealer subsequently diagnosed an intermittent open circuit involving the electric power steering rack-and-pinion/steering gear assembly and replaced the complete steering gear assembly. Despite these repairs, the malfunction has occurred again, during another occurrence while driving on the freeway, the dashboard flashed on and off and multiple warning lights and messages repeatedly appeared, similar to the condition that occurred before the steering gear was replaced. The vehicle currently has approximately 55,000 miles. The condition remains intermittent despite multiple repair attempts. I am concerned that this recuring electrical or vehicle communication failure could again cause loss of power steering assistance or affect other safety-related vehicle systems while driving.

The contact owns a 2023 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the instrument panel shut off without warning. The vehicle was restarted, and the panel remained blank with white streaks across the screen. The vehicle was towed to a dealer, and the dealer associated the failure with the instrument cluster. The vehicle was not yet repaired. The manufacturer was notified of the failure. The failure mileage was 34,500.

Traveling had an engine light come on. stopped at a dealer they inspected found multiple errors reset engine light and said continue home. when home bring into my dealer. Got home that night went to start truck, all kinds of errors started popping up on the dash, vehicle would not turn over at all. Had to call wrecker to have brought into shop. First issue could not put the truck into neutral at all, so they had to pull in park to put unto the bed of wrecker (that seems to be a very poor design of the truck). Brought truck into shop received a call two days later that it is fixed and working fine. Went to the shop asked what the problem was, told there is a ground strap under the truck that is like the main part to make sure everything works regarding electronics. The dealer has had to repair many of these ground straps, they are exposed to the elements and come loose I was told. They had two other GMC trucks in the shop with the same issue that day. the ground strap is exposed to the elements do not understand why this would not be covered just like a battery lead to stop from corroding and have to clean it or replace it. Not to mention there is no where in the service manual I can find about any maintenance that needs to be done with it. Appears to be a very bad design from the car manufacture.

The plastic upper rail glass guide frame on the rear sliding window assembly of my 2023 GMC Sierra developed structural micro-cracks during normal vehicle operation. This manufacturing defect is a known issue tracked internally by the manufacturer under Technical Service Bulletin (TSB) #18-NA-383.This structural failure allows severe water intrusion into the passenger cabin. The leaking water runs straight down the inside back wall of the cab, completely flooding and corroding sensitive, factory-installed electronic safety modules mounted directly beneath the leak path.This continuous water intrusion caused the catastrophic electrical failure and corrosion of the video processing control module located behind the rear seat. The sudden failure of this module completely disabled the rearview digital mirror camera and the 360-degree perimeter driver assistance cameras, creating immediate blind spots and an active driving safety hazard while operating the vehicle.The vehicle was inspected and repaired by an authorized dealership, confirming the rear window leak as the direct cause of the electronic destruction. The out-of-pocket cost to replace the water-damaged safety components was $2,747.00. Because the manufacturer refused to cover the replacement of the defective rear glass assembly, the structural leak remains unresolved. This active water intrusion continues to flood the cabin, creating a health hazard via mold growth and guaranteeing that the newly replaced safety cameras will inevitably short-circuit and fail again.

Model: Sierra Denali Ultimate Engine: 6.2L V8 VIN: [XXX] Mileage at Most Recent Incident: Approximately 52,000 miles Safety Complaint Summary I am submitting this complaint to report a recurring loss-of-propulsion and engine power event involving my 2023 GMC Sierra Denali Ultimate equipped with the 6.2L V8 engine. This vehicle has experienced two separate incidents in which it suddenly lost power while being operated at highway speeds. During both events, the vehicle unexpectedly lost propulsion without warning and without any apparent driver input or mechanical indication beforehand. No warning lights, check-engine lights, reduced-engine-power messages, service transmission messages, or other warning indicators were displayed prior to the failure. The vehicle simply lost power while traveling in traffic. During both occurrences, I was forced to safely maneuver the vehicle to the shoulder of the roadway while rapidly losing speed among surrounding traffic. Once stopped, the vehicle would not resume normal operation until it was restarted. After restarting, the vehicle appeared to operate normally; however, the fact that this condition has now occurred twice raises significant concerns regarding the reliability and safety of the vehicle. Safety Risk This condition presents a significant and immediate safety risk because sudden loss of propulsion during highway operation can leave the driver unable to maintain speed, safely merge, maneuver, or avoid surrounding traffic. The unexpected reduction in speed creates the potential for rear-end collisions, loss of vehicle control, or other traffic accidents, particularly when operating on high-speed roadways. Because the vehicle provided no warning before losing power, there is little opportunity for a driver to take preventive action. Additional Information • Vehicle: 2023 GMC Sierra Denali Ultimate • Engine: 6.2L V8 • VIN: [XXX] • Approximate Mileage: 52,000 miles • Number of Incident INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 55