2021 GMC SIERRA 1500 Complaints

Driving down road and had total loss of power steering and yes it is available for inspection. Almost drove it off the road due to loss of steering Yes, it happened to be a failed main grounding strap that created the issue. The dealership made the repair. No, it was inspected and repaired by the dealership Yes, started with loss of power steering, then truck died and these codes popped up: Low fuel code, but tank was full; trailer brake system code; side detection code and esc traction control code.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while her son was driving 55 MPH and depressing the brake pedal, the vehicle failed to slow down as intended. The driver attempted to use the parking brake to slow the vehicle, but the vehicle failed to slow down. The message “Braking System Failure” was displayed. The driver pulled over to the side of the road, and the passenger’s side front wheel detached and started leaning to the right before the vehicle came to a stop. The driver exited to inspect the vehicle and became aware that the front passenger’s side wheel was lying on the ground. The vehicle was towed to an independent mechanic, but was not diagnosed. The vehicle was then towed to another dealer, where it was diagnosed, and it was determined that the passenger’s side upper and lower control arms, ball joints, rack and pinion, brake rotor and pads, hub, outer tie rod, brake line, speed wheel sensor, wheel and tire, and suspension parts needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 77,000.

Driving and lost all power to truck annd lost control. Was able to coast truck with no accidents. all lights turned on dash board. Engine stating to make horrible noise. Cylinder 1 had a collapsed lifter which cause the failure. They replaced all lifters on the left side. They stated that batch of lifters were faulty. Requested to have the lifters on the right side replaced since they are the same batch but they refused. They would fix once or if they collapse but since they working they would not change them. Called GMC, reported it to them. The three people I spoke with had no idea about lifter problems and it was the first they had heard of it. Multiple complaints have been reported by customers. They did not want to give permission to replace the right side or extend the warranty. When the right side give out, if I am going at high speeds on the freeway, an accident could occur causing injury or death. I know they have a recall on prior GMC but my truck is not included.

Coolant control valve failing. Warranty not covering this part. Seems to be a manufactured issue. Happening on a lot of 2021 GMNC Sierras with the 3.0l Duramax.

My L87 engine has failed due to a manufacturing issue. The recall number for this issue is N252494000. Upon contacting GMC, they state that my VIN number is not included in this recall despite having the same exact issues. I took the vehicle into a mechanic as soon as a problem had arose.

While driving into work, I noticed a knocking sound from the outside of the vehicle. Once parked, upon further inspection I narrowed down the area of the noise to the bottom rear of the engine/front of transmission. Fortunately, I was able to park in front of my office building and wasn’t stranded on the side of the road but under different circumstances it could've been the side of a busy highway or hours from home. I had the vehicle towed to the dealership I originally purchased from, the dealership was able to duplicate the issue with me present. Later that afternoon I was informed that the engine had failed and a replacement would be ordered. There was no prior indication of a problem or warning/CEL’s. The engine failed after the dealership had completed the engine recall ( pico test and 0-40W oil change ) related to the vehicle. I am reporting this in hopes that it helps with the investigation. This has been very disappointing for me as I have supported the brand of vehicle for many years. Only to have many issues under 80,000 miles and to lose confidence in the vehicle I purchased and the company.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving approximately 45 MPH, the transmission inadvertently shifted from drive (D) to first gear. The check engine warning light was illuminated. The vehicle was pulled over to the side of the road and then towed to the dealer, where it was diagnosed, and it was determined that the valve body needed to be replaced. The vehicle was not repaired because parts were not available. The manufacturer was notified of the failure. The failure mileage was approximately 103,000.

See attached document for complaint. INFORMATION, DETAILS, COMMENTS, DATES, AND NUMBERS ON RECALL 20211500 DENALI Recall Vehicle Information: All models of GM's with 6.2L gas engine (My personal truck I owned} • Recall date: April 23, 2025 650,000 + GM vehicles with 6.2L gas engine, years 2019-2023 • Manufacturer Recall Number: N2524944000 (letter issued by State of Washington Dept. of Licensing, PO Box 9020 Olympia, WA. 98507-9020 • NHTSA Recall Number: 25V274 • 2021 GMC 1500 Sierra Denali, x-tended cab, 4wh dr, 6.2 L gas engine • Vin #: WITH 6,400 MILES ON MY TRUCK May 15, 2025 • Went to local dealer, Becker Buick-GMC in Spokane, WA., to verify there was a recall on my truck and vin. #. Confirmed with there service department and sales person Jon Stone. • I was informed that the Dealership, service dept., and salesman Jon Stone, and Sales Mgr. Cameron could only say the following: "GMC DOES NOT have the tools made yet to verify if the engine will need to be replaced and would add me too the list and keep me posted." • I was informed at this time that t he issues with the engine were: engine could stop and start again at random; the engine start to smoke and stop; the engine could catch fi re whether it was running or not, or the engine could do ALL THREE things. • I was told to just keep driving the truck but watch for any of these issues. May 28, 2025 • Stopped in local dealer, Becker Buick-GMC, again to see if any updates. • Told GMC still had done nothing to develop the necessary tools to evaluate the engine and had no date to report or share with me on when they co uld. • Again, I was told to keep driving the truck and if I had a problem, Becker Buick would come and tow me. • Salespeople did ask if I wanted to just buy a new truck several times. They were impressed my truck only had 6400 miles on it and in such excellent shape. This was to be my retirement truck. June 5, 6, 7, 2025 • I visited several car dealers in the Spokane, WA. Area. Ford, Chevy, Dodge and Toyota. While looking at new/different vehic

I have a 2021 GMC Sierra 1500 AT4 3.0L diesel pickup truck with 98,500 miles. The coolant control valve failed on my vehicle and for some reason it is not covered under GM's special bulletin that covers this part 15yr/150,000. Ridiculous.

Began with a misfire on cylinder 5 code P0305. Replaced spark plugs, wires, and coil pack. Misfire still existed. Fuel injector on cylinder 5 was stuck open and had to be replaced. Misfire still existed. No spark from new coil pack on cylinder 5, replaced coil pack connector. Misfire still existed, but lifter tick became present. Removed cylinder head and found exhaust lifter on cylinder 5 was bad and needed replaced. Currently awaiting parts delivery (only available through GM dealer). Have been without vehicle for 7 weeks now. Was told this was most likely related to Active Fuel Management.