2025 GMC Sierra 1500

My vehicle is equipped with multiple safety systems offered by general motors. Since purchasing my vehicle new, I have had a persistent and recurring issue related to the vehicle safety system, which is resulted in numerous collision detection and advanced cruise control service is not functioning as designed, creating safety issues for both myself and potentially other motorist on the road. Additionally, the parking sensors are not working as expected, presumably due to the same issue, which has resulted in numerous safety concerns, including the detection of vehicles or objects, which were not present, resulting in the systematic breaking function engaging posing a risk to myself and surrounding motorists. I initially reported the issue to GM on 2/20/2025, when the vehicle had 467 miles on the odometer. Since the issue initially began, I have returned to the GM service department at my local dealer a total of seven (7) times. The local service department has been in contact with GM corporate office related to the issue, however, they have been unable to rectify the issue and continue to send the vehicle back out on the road claiming the issue has been resolved only for it to recur shortly thereafter. I believe that GM providing the safety features in an inoperable state poses great risk to the general public, and the NHTSA should investigate this issue alongside the other active systemic issues GM is currently under investigation of. At this time, it is unknown what is the cause of the issue, multiple parts have been replaced, and the true cause of the issue has been undiagnosed.

The vehicle will loose all interior audio to include stereo, turn signals, and all other audio safety features for several hours at a time. GMC has done three repairs and still no resolution. Lack on audio impacts the safety of the vehicle. Has happened dozens of times and appears to be larger GM issue that is u resolved. Has occurred at least 20 times since I bought the vehicle 10 months ago.

The engine seized and locked up leading to a catastrophic failure of my three month old 2025 GMC Sierra Denali at approximately 3,181 miles. The engine, the 6.2L V8, was listed as a recall engine by GM for model years 2021-2024. My 2025 allegedly "passed inspection" yet had the same catastrophic failure. The vehicle engine made loud noises and it sounded like parts were breaking. The vehicle no longer starts and had to be taken via flatbed to the dealership where I was informed the engine had to be replaced.

The vehicle has a vibration and stuttering feel during highway driving. Cruise between 70-75 has off and on again vibration is seat, steering wheel, and center console. The issue feels more pronounced between 60-65 and exhibits more of a hum, much like a washing machine drum that is out of balance. I have had the truck at 2 different dealerships and they have insisted it was a whee balance issue. I have also had the truck balanced at Costco. None of these issues have been alleviated with wheel balance. The dealership, where the truck was purchased, refused to test the truck at highway speeds and would only drive it for a short period at speeds up to 55mph. I have also reached out to GMC customer service, and they simply regurgitated what the dealer indicated about balance and testing at 55 mph or less in town. There seems to be a number of TSBs out on this issue. Most related to torque converter issues, but none of the dealers have indicated that my truck is impacted by any of the current TSBs, even though it exhibits all the symptoms. Not sure of the safety replications, but I am disappointed in the fact that the truck has had this issue since around 1,000 miles, and it seems like the dealer service departments are just ignoring it and refusing to do a thorough evaluation of the issue unless a code triggers or until a major failure occurs

- On 9/23/2025 while driving down the main street, the vehicle unexpectedly shut down (engine stopped running) and would not restart. The vehicle is currently at Elevation GMC (Boone ,NC) waiting to be diagnosed. - Safety was put at risk by the vehicle unexpectedly shutting down in the middle the of rush hour traffic and not being able to be moved. - When it is was towed into the dealership and explained to the service manager what happened; she said "there is a known problem with the gear select lever losing communication with the truck and not knowing what gear it is in". - As of 9/24/2025; dealership has not looked diagnosed what the problem is/was. - There were no prior warning messages before the engine shut down.

--Radio power button inoperative --Radio channel change buttons, to left of steering wheel inoperative (everyday) --Radio volume inoperative -just stops working (sometimes) --Radio “HOME” button, left of radio power button inoperative --Driver door mirror wobbles when above 50 MPH (very distracting when driving) --Driver door hard to close and out of alignment --Dealership is selling the vehicles KNOWING some of the issues are present, but not advising the buyer. My safety is/was at risk due to having to move my hands off the steering wheel to touch the radio display to make any changes while driving. A certified GM service dept confirmed all my issues and could not repair. They quoted a PIT 6408. However, this particular PIT does not address my issues/concerns.

I purchased a 2025 GMC Denali a few months ago. At approximately 7,000 miles, the front brakes failed unexpectedly and were replaced by the dealership. However, by 14,000 miles, I began experiencing brake issues again. Before I could return the vehicle for service, I was driving on the turnpike when the engine suddenly seized without warning. This created an extremely dangerous situation—vehicles behind me nearly collided as I lost power and control. I managed to pull over safely, but the tow truck operator struggled to load the vehicle due to all four wheels locking up and the engine being completely seized. Once the vehicle was inspected at the dealership, I was informed that the engine had failed and would need to be replaced. I am aware of the recurring issues associated with the 6.2L GMC engines and related component failures, and I no longer feel safe driving this vehicle. Given the repeated mechanical failures and the serious safety risks involved, I am formally requesting that GMC initiate a buyback of this vehicle. I believe this situation qualifies under lemon law protections and warranty obligations, and I urge GMC to take immediate action to resolve this matter.