GMC Complaints

Upon starting the vehicle, I got multiple warning lights. The most important was brake failure. I had no brake function. I took it to the dealer and they replaced the brake module after 3 days.

the Engine started running rough and the engine light came on. The dealer told my wife to drive there in limp mode (~15 miles), she did so on back roads. The diagnostics said that cylinder 7 was not firing and teh fuel injector control circuit was bad. they had to replace the Engine Control Unit.

I am writing to formally file a safety complaint regarding the ongoing recall of the GMC/Chevrolet 6.2-liter V8 engine and what I believe to be an inadequate and insufficient remedy being provided to vehicle owners. I purchased a brand-new 2023 GMC Sierra AT4 equipped with the 6.2-liter engine. I drive approximately 6,000 miles per year and maintain the vehicle carefully. After receiving the recall notice, I promptly took my truck to an authorized GMC dealership for inspection and repair. The only action taken was an oil change to a heavier-weight oil. I was told that everything was “fine” and that no further action was required. I find this remedy unacceptable given the severity and nature of the reported failures associated with this engine platform. Simply changing to a heavier oil does not address the underlying mechanical risks and does not provide owners with meaningful assurance that catastrophic engine failure will not occur without warning. This issue is particularly serious for me because I rely on my vehicle for my livelihood. I am an account sales executive and use this truck extensively for work travel and customer meetings. If my vehicle were to fail unexpectedly, it could cause me to miss critical business meetings, resulting in immediate financial loss and potentially long-term damage to customer relationships and sales performance. The current remedy provides no confidence that such a scenario will not occur. In addition, this recall has materially harmed the resale and trade-in value of my vehicle. Dealerships are now significantly lowballing trade-in offers because the 6.2-liter engine recall is widely known and prospective buyers are reluctant to purchase these vehicles. Buyers are also aware that any future owner will not receive the benefit of the original powertrain warranty coverage in the same way, further depressing resale value. As a result, I am effectively trapped in a nearly new vehicle that has become difficult to sell or trade due

My vehicle stop running as I approached a traffic signal and failed to restart, it happened at a heavy traffic intersection during morning commute,I had the vehicle towed to Dealership that same day (01-22-2026). Later that evening the dealership called to inform me that the motor was blown and had ordered a new one.the mileage is approximately 39,285.

While traveling 60 mph on a divided highway went to pass another vehicle. Had no throttle response the engine had completely turned off, locked up seized up. I’m not sure what caused the engine to just lose all power. Had to go back to the lane and luckily there was a turnoff where I was able to turn off the highway.

My 6.2 engine locked up and left me stranded. Had it replaced with s new engine on 10/31/2025 and I'm having problems again with it. As well as my 10 speed transmission slipping and hunting for gears

I was driving on the highway (using cruise control) when the front bumper grill started vibrating (so I tried to slow down) but it kept flapping and flew off before I was able to pull over. I then pulled over on the shoulder and had to walk back to retrieve it. My safety was put at risk because it could have hit my windshield and caused me to have an accident, or, it could have hit someone or another vehicle. I have it and it is available for inspection. It has not been inspected by anyone yet. There were no warning signals prior to the failure.

Tailgate is randomly dropping while driving without any tailgate drop buttons being pushed. It’s is starting to occur more frequently.

Driving after dark on a main street in St George Utah, the engine suddenly surged and then revved down. It felt like someone jamming it into 4WD. Traffic was tailgating me, and I was nearly hit. I could not pull completely out of the right lane. I put on hazard lights. Check engine light came on, and TCS light came on. I decided to get out of traffic & crawled forward about 30 yards into a Sinclair station lot, then backed it into a spot where a tow truck could get it. It was clearly not drivable. Called AAA and a driver was able to get to me within 1/2 an hour. Checked the AAA website for mechanics since I was merely travelling through St. George and had no knowledge of the area. Hawker's Automotive was listed first, with many excellent reviews. Tow truck arrived and driver loaded it on the JerrDan bed. I asked him to take me to the Hawker's garage location. I locked it and put the key in the overnight box with my name, number, and description. Next day the mechanics said lifter arm was collapsed. Needed tearing down, replacing and probably new camshaft. Gave me estimate for "estimated" repair of about $8,000 or new engine at about $12,000! This is a KNOWN GMC failure apparently. Recalls have been initiated on newer models, but every mechanic will tell you that this happens all the time to all the 6.2L, V8 engine at around 150,000. I bought it used at about 156,000 miles and have put about 5,000 miles on it. And changed the oil at purchase, and about 1,000 miles ago. I researched model and year before purchasing. All online reviews I found were positive. Nothing out there on this know manufacturing flaw. But now when I type in 'catastrophic engine failure 2016 Denali XL" many many reviews and videos state that it is a known problem to both GMC and NHTSA. I or someone could have been killed by such a dramatic loss of power! This is a SAFETY issue and NHTSA needs to review ALL THE COMPLAINTS ON FILE ALREADY. Thankyou

I have a 2024 GMC Denali that had an engine service appointment in September 2025 for the engine recall where they did an oil change & put in performance grade oil & scoped my engine. Rochester Serra GMC said they sent all the engine pictures to GM and my engine was okay according to them. After that appointment in November my engine light went on and my Denali was leaking oil in my driveway. We took the truck back to Serra GMC Rochester and they replaced the oil filter that they said was defective & an oil change was done after my husband requested that just filling up the oil was not okay. They also told us the engine light didn’t show up on their computer system and it must have cleared out, so nothing was done for that. Today 1/25/26 now about a month later my engine light is back on and has remained on with multiple starts. This is not acceptable and needs to be investigated and I want this escalated. I do not feel comfortable driving my truck with this engine light on with a known engine propulsion recall that has no actual cure. The oil replacement and cap change has done nothing and engine light remains on. I just don’t want to hear the same thing that the computer must have cleared the error code. My engine light is on for a reason and I’m asking for a thorough diagnostic test to be done by a certified technician and a get a valid explanation of why my engine light keeps going on & not just changing my oil or waiting for something catastrophic to happen to me or my family. GM is putting me and my family at risk by saying that my truck’s engine is fine when clearly the engine light keeps repeatedly going on for 3 months in a row now since November 17, 2025.