Truck acted like it would not start several times in a day. Had battery replaced and it still did not fix the issue. Was told by dealership I would need to bring in and let them look at it. Was going to delearship and noticed a llight knocking in my engine then all of a sudden lost power. Was able to coast out of traffic and onto a curb. Truck would not start or even try, yet every light and such still worked. Had taken to dealership and this morning was told it was the engine.

- Campbell, TX, USA

I was driving along the freeway with my family of five. There were no warning lamps. There was an odd noise for about 10 seconds, and then the engine completely seized/locked up. I lost all ability to use the engine. I was able to come across three lanes of traffic, thankfully, without hitting anything without the ability to accelerate. GMC dealership inspected the car the next day. The engine is completely seized up. They are replacing the entire engine, but it has been a month without my car. They still do not have the parts available. We are fortunate. There were no other cars around us and I was able to steer to the Berm Across three lanes. This could-??ve caused a catastrophic accident for my family.

- Blacklick, OH, USA

There was noise in the engine area and after truck stalled

- Rochester, NY, USA

While driving along [XXX] in northern Arkansas the on [XXX] my 2023 GMC Sierra Denali's 6.2 engine suddenly locked up causing us to pull on to the shoulder of the road - nearly causing an accident. The vehicle had 23000 miles on it at the time. We were towing a two horse trailer with one horse aboard. At our expense, we had the vehicle and trailer towed back to St. Louis, MO then to O'Fallon Buick GMC. The dealer replaced the entire engine under warranty with a used rebuilt engine. They have omitted the engine replacement from the vehicle history report in CARFAX. The dealer had handled a number of 6.2 engine failures prior to this one. The vehicle was serviced well within factory guidelines at the dealer. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- St. Louis, MO, USA

While I was driving, the dash screen read "Press start button" and suddenly the vehicle loss engine power and I had to veer to the far right lane. Luckily the cars around me swerved away. I had initially called OnStar, but when the police arrived they told me I couldn't wait for Onstar as I was impeding traffic so they called a local tow truck and they towed it to my house. From my house, OnStar towed it to the GMC dealership. The dealership stated the engine has locked up and needs a whole new engine replacement.

- Pelham, NH, USA

While driving at about 70 mph, the screens in the vehicle went black and the truck had a complete loss of power. The vehicle inadvertently braked to approximately 30 mph and went into limp mode. The check engine warning light came on and the service power steering warning light, the service transmission warning light, the low tire pressure warning light, and the traction control warning light all illuminated. There were also messages displayed on the instrument panel to Service 4-WD and Reduce Acceleration and Drive with Care.-??

- Panama City, FL, USA

I was driving on a rural and narrow 2 lane road with next to no shoulder when my engine started losing power. There were no check engine lights or other indicators of failure until the final 2 seconds. At that point, a message popped up on the dash stating something along the lines that my engine oil was too hot and to idle the engine. 2 seconds later, at 50mph my engine died. That is scary enough, but I was also towing a 5,000lb+ trailer, it was -3F, heavy winds, and I had my 2 dogs with me. Thankfully, I kept my wits about me, remained calm, and made it to the side of the road. As mentioned, there was not much shoulder so this put me in great danger of being hit by careless drivers speeding by. The nearest police officer was an hour away, so I was in quite a predicament. Had this happened to most other people, the narrative would have ended much differently. Come to find out, this is a common issue with these 6.2l engines. So much so, that there is a backorder on the engines due to the high replacement demand. This poses extreme danger not only "in the moment" of failure, but also the environmental dangers/risks users are potentially exposed to, just as I was. This needs to be a recall as this is a substantial and immediate safety issue in my opinion.

- Buffalo, MN, USA

The contact owns a 2023 GMC Sierra 1500. The contact stated the vehicle was consuming excessive oil consumption. The contact mentioned that the vehicle was consuming oil every 2,000 miles. The vehicle was not taken to a dealer. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure and confirmed that the vehicle was consuming oil at a regular timeframe. The manufacturer advised the contact to have an oil consumption test. The failure mileage was 21,000.

- Scottsdale, AZ, USA

The contact owns a 2023 GMC Sierra 1500. The contact stated upon attempting to start the vehicle remotely, the lights illuminated; however, the engine failed to turn over. The contact stated that upon pressing the Push to Start button, the message "Service Braking System" and other braking system messages, and message that the "Top Speed 43 MPH" were displayed. The check engine warning light was illuminated. Additionally, the contact stated that the vehicle experienced reduced braking while driving at various speeds. The vehicle was taken to the dealer where an unknown software update was performed; however, the failure recurred. The contact stated that the failure occurred intermittently. The vehicle was taken back to the dealer, where a service representative scanned the vehicle and informed the contact that diagnostic trouble codes were retrieved; however, the dealer later informed the contact that the failure could not be replicated. The contact used a scanner to scan the vehicle and retrieved diagnostic trouble codes. The manufacturer was notified of the failure and a case was opened. The manufacturer later informed the contact that they could not assist because the dealer stated that the failure could not be replicated. The failure mileage was unknown.

- West Islip, NY, USA

Coolant control valve malfunction Vehicle placed into limp mode while driving with no way to reset. Vehicle taken to dealer and issued verified with part ordered. Multiple dash warning lights and several different limp modes activated prior to vehicle needing to be stopped

- El Paso, TX, USA

Failing coolant control valve causing reduced acceleration warning and engine overheating. Replacement parts unavailable from GM. Vehicle has been at dealership for a month and showing symptoms sporadically since the first few thousand miles getting increasingly worse over time. Reduced acceleration caus d many unsafe incidences when on the highway.

- Manchester Center, VT, USA

Coolant control valve has failed. Part is back ordered and availability unknown. Truck goes into reduced power mode which makes merging into traffic unsafe.

- Hudson, NY, USA

Coolant control valve failure. The 3.0 Duramax Diesel engine coolant control valve is known for failure. The part is not available and it has no availability time frame from GM. Vehicle goes into reduced acceleration mode hindering driver from being able yo accelerate safely in traffic.

- Naples, FL, USA

While driving my 2023 GMC Sierra 1500 Denali, 6.2-liter engine on the highway, the engine seized at 22,000 miles. GMC has been working on my truck since 9/7/24 and still no truck. The end state is, I was told by the Service Department that there is a design flaw with the 6.2-liter engine (something with the intakes valves being too large, resulting in the valve bending seizing the engine). I was also told, this dealer had two other trucks there now with the same seized engine. Their plan is to install a new engine with the same design flaw with the hopes it does not happen again. This was an extremely unsafe condition as I was travelling at 65 miles per hour on the highway when the engine seized, luckily, I was able to coast to a large shoulder after almost getting into an accident when it seized going uphill.

- Chantilly, VA, USA

Engine goes to limp mode multiple times 3 of which happened getting onto the highway and almost creating an accident due to the reduced acceleration mode. CODe u0656 00 popped up each time. Dealer has yet to rectify due to lack of appointments-?? making me keep the vehicle saying it-??s drivable but each time randomly goes into the reduced acceleration mode every restart. (Blasius GMC Branford CT)

- Brandford, CT, USA

In late February/early March, my GMC Sierra with around 9000 miles had the following to occur on a cold start: check engine light came on as well as the service esc light & traction control light, truck shuddered and shimmied. Took for service on March 4, 2024 with 9774 miles on odometer, where service tech said they couldn't duplicate concern (see attachments: March Service Invoice Pg 1 & 2). Took truck home & same issues kept occurring especially on cold mornings & days. Took the truck back for service on April 1, 2024 with 10895 miles on odometer. Told them to keep it till its fixed & to start it on cold mornings because thats when problem occurs. They had truck till April 12, 2024 and were able to duplicate the concern. Dealer changed the fuel injector (that was not the problem). Service tech finally found the cylinder 8 has a misfire until vehicle gets to operating temperature. They replaced all 8 lifters in bank 2 (right side) & gave me an oil change. This seems to have fixed the problem, but I won't really know until winter 2025. My problem with this lifter issue is that this engine will probably only last for 3 maybe 4 years tops because of all the metal shavings that are roaming around in the engine. This has been a problem with GM engines for some time & GM has yet to fix it or at least take responsibility for their poor engineering. I paid over $70,000 (of which GM made around $17,000) for this truck only to have the engine probably make it for a few years. My last truck I kept for 10 years. I don't see this happening with this truck.

- Summersville, WV, USA

The transmission failed as I as was turning on to a highway. It seemed like it was rapidly shifting between two gears, but I could not accelerate for several seconds and had to immediately pull over into the ditch to avoid a high speed collision. I took it to the shop the next day. The transmission valve body failed, which appears to be a common issue as I've researched incidents like this online. The part was on backorder. Once it arrived at the dealership, the replacement valve body immediately failed again. Now a 3rd valve body is on backorder with no ETA. I've been without my truck for over a month now with no end in site, and I do not have confidence that a 3rd replacement is going to provide a proper and long lasting fix.

- Van Alstyne, TX, USA

The contact owns a 2023 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the vehicle started to shake abnormally with the check engine warning light illuminated. The contact stated that after arriving at a parking structure, the transmission warning light illuminated. The vehicle was towed to the local dealer where it was diagnosed with transmission failure. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 15,000.

- Los Angeles, CA, USA

The contact owns a 2023 GMC Sierra 1500. The contact stated that the vehicle was idling excessively high without the accelerator pedal being depressed. While driving 70 MPH, the tailgate unintendedly opened. The tailgate warning light was illuminated. Additionally, the blind spot detection warning light illuminated without another vehicle being nearby. The vehicle was taken to the local dealer, who was unable to duplicate the failure. The vehicle was not diagnosed or repaired. The manufacturer was not contacted. The failure mileage was approximately 6,100.

- Wichita, KS, USA

Truck has died going down the road at 40mph. Also have electrical issues with radio..running boards opening going down the road. No sound from radio, signals...no connections to google on star lost. Radio screen half of screen shuts off. Front crash sensors go off with noting in front of vehicle...loss of cameras no connection. Sounds like a bug zapper under truck. GM has reprogrammed truck now 3 times sent a tech from factory...replaced radio reprogrammed all computers again!! truck has been in the shop this time for over 30 days with 6200 miles on it this is the 4th time since I bought in June. Have a case representative from GM who will not help with issues just keeps putting me off. Have videos pictures of all the issues and have given to dealer and

- Pekin, IL, USA