2021 GMC Sierra 1500 complaints

The contact owns a 2021 GMC Sierra. The contact stated that while driving at approximately 40-45, the engine warning light illuminated. There was an abnormal sound coming from the fan. The vehicle was taken to the local dealer, where it was diagnosed and determined that the coolant flow valve needed to be replaced. The vehicle was not included in a special coverage program. The vehicle was not repaired. The manufacturer was not contacted. The failure mileage was approximately 50,000.

The problem is in the power-locking manual tailgate’s exterior release switch assembly. Water intrusion into the switch can cause a short circuit, leading the tailgate to unlatch while the truck is in Park. Once moving, momentum and air pressure can cause the tailgate to open further, potentially dumping cargo onto the road and creating a hazard.

My vehicle began exhibiting symptoms consistent with a failed Engine Coolant Flow Control Valve. The check engine light illuminated, and diagnostic testing indicated a fault related to the coolant control valve system. In addition, I experienced abnormal cooling system operation, including the engine cooling fans continuing to run after the vehicle was shut off. Vehicle was tested few times in Auto Zone These symptoms affected the normal operation of the vehicle and are consistent with the condition described in Special Coverage N252508341. Based on the diagnostic findings and vehicle symptoms, I believe my vehicle qualifies for coverage under this program. I respectfully request that my vehicle be inspected and evaluated under Special Coverage N252508341 and that any eligible repairs be performed according to the terms of the coverage program.

While driving my vehicle, the engine and transmission lost power and the check engine light came on. The vehicle went into limp mode and engine propulsion was limited. Had I been traveling at a faster speed, this would have been very unsafe. After coming to a stop, placing the transmission in reverse did not move the vehicle and there was a grinding noise. I was able to savely move forward in limp mode, but the shifting was harsh. I was able to find an empty parking lot to safely park. The truck was towed to Jim Winter dealership in Jackson MI for inspection.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the reduced power mode and Check Engine warning lights illuminated. The vehicle was taken to the dealer, where it was diagnosed with coolant control valve failure. The contact was informed that the coolant control valve needed to be replaced. The vehicle was not repaired. The contact was informed that the failure was like the failure description in Special Coverage Bulletin: N252508341. The manufacturer was made aware of the failure but provided no assistance. The contact was informed that the VIN was not associated with the Special Coverage. The failure mileage was approximately 58,500.

When pressing on the gas, especially when moderately accelerating, the truck experiences severe shaking, which interferes with acceleration, as well as causing the truck to "jump" when the transmission gear "catches", even while driving. When the truck is at a full stop and the engine is auto off, when it restarts, it does so frequently when it reengages that it causes a physical "jump" in the vehicle, causing the driver's foot to come off the brake pedal. This has been most noticeable since my vehicle hit about 70k miles. I currently have 84k miles. I engaged the dealer and was told the transmission is out of warranty. I see that other GMC Sierra models suffer similar problems and recalls have been issued to GMC that they must repair those vehicles. Despite that, my vehicle is not included in any current recall program.

So I made an appointment to have my truck recalled and the Wednesday before I took it, and it cranked no start and I called the dealership. Ask if they had any other those like this and they said that it could be the fuel injector module and so I got it to a mechanic shop to read the codes and it gave me a code p062b and I asked the dealership to look into it and they never figured out what we were not wrong. I just testing the battery. Well, then I got it back after the recall was done and new transmission valve body put in and about 30 miles down the road it started to shake violently and had a flashing engine light so I got it home called the dealership the next morning because they were closed set up another appointment got it to the dealership dealership said it had a couple misfires but since it wasn’t over 100 they weren’t concerned even though I’m pretty sure it is related to the fuel model going out because it has been cranking rapidly whenever I try to start it, but they won’t do anything to figure out what’s wrong?

Engine Coolant Control Valve Position Sensor Minimum Stop Performance, and Chevy recalled this on this same motor and GMC needs to pays for this as it’s a major problem!

While coasting down or under very light acceleration between 12-20 mph the vehicle has a shudder like driving over a highway rumble strip. While cruising on the highway at 65+ mph, the vehicle has a light shudder or vibration. Vehicle has been checked numerous times for wheel and tire inconsistencies. Brake pads and rotors have also been replaced with no change in issue. Headlights daytime running light changes color from bright white to purple during warm weather. The vehicle has been to 3 different GM dealerships and they acknowledge the issues but do not provide a resolve.

While driving home, the engine began to run very rough with decreased acceleration, obvious overall loss of power and a significant amount of white smoke being emitted from exhausts. Several alarm indicators and codes started flashing on instrument panel including Check Engine, Service ESC, Steering Assist Reduced, and Service Parking Brake. Had truck towed to dealership. From Dealership Repair Invoice: Truck scanned with diagnostic codes 0300, 0302 present. Dealership removed right side valve cover and found rocker does not move when engine running. They removed the right side head and found cam and lifter damage. Camshaft, and all 16 lifters were replaced as per document 5659832 under warranty. Labor was 23.3 hours plus 1.2 hours to recover and recharge A/C system.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while The vehicle while operating the vehicle a knocking noise was present coming from the engine and the check engine warning light had remained illuminated. The vehicle was examined by an independent mechanic who diagnosed that the engine valves had malfunctioned and engine needed to be repaired. The vehicle was not yet repaired. The manufacturer was notified of the failure but no assistance was offered. The manufacturer was notified of the failure. The contact was informed that the VIN was not included in the NHTSA Campaign Number: 25V274000(ENGINE AND ENGINE COOLING). The contact indicated that the vehicle had experienced that same failure listed in the recall. The failure mileage was 98,000.

Vehicle will not consistently shut off. Shift to park error received upon trying to shut vehicle off. Concerns on if the vehicle is actually in park and if it is safe to exit vehicle. Concern that vehicle is not in park and electrical units aren’t being properly shut down (i.e. radio).

Power steering locked up while driving. multiple dash lights turned on, on its own after the issue, 4wd, emergency brake, abs, and other ones im not sure what they are. took it to the dealership for a recall and told them the issue that happened.

Power steering locked up while driving. has been inspected and repaired by manufacturer. recall.

Catastrophic engine failure the connecting rod went through the block. It is my understanding that Defective Components: Manufacturing defects in the connecting rods and crankshafts can reduce oil film strength, leading to severe wear, metal debris, and catastrophic engine could be the proiblem

The truck randomly will not detect that it was shifted into park. Shifting between gears and back to park does not automatically fix the the issue and has taken up to 10 mins to turn the truck off. The adaptive cruise controls stopped working and can still use regular cruise control. Just not adaptive. It appears greyed out. The truck has thrown the error code: P1098, Engine Coolant Control Valve Position Sensor Minimum Stop Performance. The truck would go into limp mode until the error was cleared. This error has appeared 4 times over the past five months. The most recent date of it happening was today. 06/30/2026

The truck has a studder that comes from the transmission when at highway speeds. the studder can be felt at random intervals (seconds) from all passengers. The studder is also present on starting up a slope or accelerating from a stop at a slow pace. when accelerating slowly the jerk is more prominent. We have taken it to the GM Dealership, they confirmed the issue was present. The dealership said the GM guidence was to 1st try a re-program and then replace the torque converter. The program flash was unsuccessful, then we paid $4000 to change the torque converter. The Tech stated that this was the GM suggested fix, but noted that we are changing the fluid also which could mask the issue if it is the valve body causing an issue. The replacement torque converter and fluid did somewhat reduce the issue for a short period of about 2 months before it has returned as it did before. The next option from the dealership is in excess of $8,000 for a remanufactured transmission which is outside our reasonable spend, when we dont expect the remanufactured transmission will have any better valve body components. The recent recall did not cover my gas 6.2L sierra 1500, although it clearly is insufficient stating that it just a warning that there is a safety risk present. The valve body of the transmission appears to be an issue across all models and the recall addresses that it is present. We continue to drive this as the primary family vehicle with the hesitation and jerking present as GM

My truck will not start when I press the push-button ignition. After waiting a few seconds and trying multiple times, it typically starts on the third attempt. Additionally, it will not restart after the auto stop feature activates at stop signs or traffic lights. This is very concerning, especially when pulling into oncoming traffic, as I’m worried the truck could shut off while I’m crossing. I have already had the battery, starter, and alternator checked, and all components tested fine. However, the issue is still occurring. There are also no warning lights or messages displayed on the dashboard.

While driving at normal highway speeds, I got a warning light for engine overheat condition and cooling fans came on. I also got a warning that the engine would go to reduced power. I reported this issue to my local GMC dealer. Was told that this was a comm problem with this engine however: my vin number indicated that this vehicle was not covered under warranty N252508341. I was advised to bring it in for a $250 diagnostic check and repairs could not be made for at least 2 months because of backlog. Took my truck to a local vehicle repair shop where they diagnosed a faulty coolant control valve and replaced it for me for $2388.43. Why did GMC desert me?

Shift to park dings continuously and vehicle won’t turn off draining battery leaving doors unlocked. Don’t want to force into park and break anything more.

2021 GMC Sierra AT4, VIN [XXX] , NHTSA Campaign 25V-274, GM Case XXX. Brake pad monitor failed at 128,923 miles -- 24 miles after leaving Penske Chevrolet (released at 128,899, RO XXX, 04/17/2026). Brakes became spongy immediately following service. Monitor disabled entirely to stop recurring red Service System alert. Root cause is a burnt fuse block ground fault confirmed in writing by two GM-authorized dealers. Ray Skillman (RO XXX, 06/05/2025) documented the fault then deleted Labor Operation 14BUZ ENGINE ELECTRICAL from the recall repair work order. Penske documented verbatim: "all of these other faults share this same ground circuit." The recall repair at Ray Skillman used a remanufactured short block instead of a complete engine per N252494002. The original seized-engine oil pan has never been replaced across three dealerships and 128,000 miles. GM's own Part 573 filing states this defect "increases the risk of a crash." I drove 300 miles on an interstate on 04/22/2026 with active brake warning and no loaner because GM Executive Resolution refused to authorize one. Three GM dealers have inspected this vehicle. GM Executive Resolution Team [XXX] ) has not returned calls or emails and has not confirmed in writing this vehicle is safe to operate. OnStar issued a Critical Alert for P0617 on 04/15/2026. Zero brake faults existed in the 13 months prior to the Penske visit. This is a direct continuation of unresolved electrical damage from a botched federal safety recall repai

Coolant Control Valve

Right after i bought the car I had a very bad misfire on cylinder 1, the car would shake at idle. Took to dealership and they said they replaced all the spark plugs and replaced cylinder 1 coil. about a week later the misfire and shaking started again but this time it would come and go. the check engine light would be on then it would go away for a bit and then come back on over and over again. The only thing that seemed to work is if i disabled the stop and go start system and put the car in L9 to disable the AFM. This seems to work and I have since bought a disabler for these systems. However, there is still a vibration at idle and i feel that its a temporary fix to a bigger issue. This is my daily driver and constantly have my children in the car and just want the car to be safe for everyone. The transmission downshifts rough and at times seems to slip/lock up while driving. I haven't brought it to the dealership for this as of yet.

Engine has a terrible shake, and I was informed by a mechanic that it has a misfire and no compression in piston number seven

I have the same model and year for GMC as bulletin 25NA-185, Engine Coolant Control Valve Failures on 3.0L Duramax (Dec 4, 2025), and am experiencing the same exact issue. Apparently my VIN is not included and I can't get an answer from GMC or the local dealer why it's not covered or how to have it reviewed to be added.

Coolant control valve not working correctly exhaust fan on high all the time but is never overheating this has been going on for a week it shows there is a 150000 mile warranty on it but not for mine

Coolant control valve has failed and caused the check engine light to occur is available for inspection. Could cause the car to overheat and cause harm to myself or others Yes has been confirmed by dealer No GM has a special coverage out for the specific vehicle and model years for this vehicle, but are stating that my vehicle does not pertain to that coverage.

The contact owns a 2021 GMC Sierra LD Crew. The contact stated that while driving on the highway at an undisclosed speed, the vehicle's bedrail attachment fully detached from the vehicle. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was unavailable.

Engine coolant control valve needed to be replaced. Special coverage (N252508341) was issued out by GM to fix this problem on 2021 GMC Sierra 1500 vehicles.

Driving normal traffic . Started hearing ticking . Check engine light flashing ,service esc and braking system light up. Parking not loud ticking from engine bay

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.

Engine coolant control valve

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

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.

6.2 lifter failure at 44500 miles

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.

THE ENGINE COMPLETELY SHUTS OFF WHEN I STOP AT A STOP SIGN OR STOP LIGHT. I HAVE BEEN STUCK IN TRAFFIC INTERSECTIONS ON SEVERAL OCCASIONS UNABLE TO MOVE WHEN THE LIGHT TURNS GREEN. EVENTUALLY THIS WILL LEAD TO ME GETTING REAR ENDED AND PUSHED INTO IN THE MIDDLE OF AN INTERSECTION. MY LIFE IS IN DANGER WHEN I DRIVE THIS VEHICLE. I GOT MY ENGINE REPLACED AND STILL THE SAME ISSUE IS OCCURRING WITH THE AUTO STOP AND START SYSTEM.

There is a recall on the 6.2 motor that is in my truck at my last oil change they performed a pico scoop diagnostic on the truck said it passed and gave it the new type of oil and oil cap that was suppose to fix it. Now a couple months later I walk out start my truck to let it warm up and after starting all of a sudden the engine started nocking bad and loss of oil pressure and on dip stick. I looked it up and this is what happens when the engine fails due to the massive recall on the 6.2 engines. I called the dealer and they are having me tow the truck potentially at my expense for them to look at and decide if it falls into the category of the recall after they did the test, and at one point told me that cause they did the test it is no longer recalled. I am being told people who have had the engines replaced because of the recall that the replacement engines have failed as well. I have a 9 month old baby and this left me stranded and unable to pick him up from daycare I had to scramble to find somone able to do so. I'm concerned that this could have happened while driving and having him with me or being left stranded somewhere.I'm glad it didn't happen when I was dropping him off that morning and while I was driving And meanwhile while they look at the issue and decide weather this falls under there recall or not and while it gets repaired I'm left without a vehicle and to be honest I don't feel safe even if they do repair it as there seems to not be an actual fix to the s

-The engine in my 2021 GMC Denali 1500 with the 6.2L engine failed its second engine with ~4,000 miles on the new engine. It is currently at GMC dealer waiting for a 3rd new engine. - Fortunately i was parked when the failure happened and the engine locked up. -Dealer confirmed that a valve dropped and damaged the cylinder wall. - There were no warning lamps or other indication that a failure was about to happen. -Current mileage ~91,000. First motor changed ~85,000 due to recall with previous owner.

P1098 code coolant control valve fail service bulletin N252508341 my vin not covered but same motor and same part !

I believe the torque converter is failing. While driving approximately 38 mph and also 48 mph up to 51 mph the vehicle have a vibration feeling like driving on a rumble strip. If you maintain the same speed, the vibration continues if you speed up, slow down, or let off the gas it goes away. There are so many detailed explanations on forums and social media from other customers experiencing the same problem, but not seeing any recall made by GMC.

Loss of steering, erratic steering control. Steering locks up

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving approximately 50-65 MPH on an incline, the contact believed that the transmission was slipping or there was a misfire coming from the engine. The contact stated that the vehicle failed to restart automatically after the engine AUTO Start/Stop system was engaged after a complete stop. Additionally, the contact stated that after driving for a while, the vehicle went into LIMP Mode. The check engine warning light and other warning lights were illuminated. The vehicle was taken to the dealer to be diagnosed. The contact related the failure to GM Campaign Number: N252515590 (Corroded Ground Strap); however, the dealer had informed the contact that the vehicle was not covered because the VIN was not included and there was no warranty coverage on the vehicle. The vehicle was not yet diagnosed or repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 75,000.

Tires are LT275/65R20. While driving on interstate at approximately the speed limit and low 80 degree temperatures in South Carolina with proper placard pressure tire inflation checked two days prior, the truck developed a faint vibration which got worse over three or four miles. I slowed my speed and pulled over at next offramp and visually inspected truck for signs of vibration. Including looking over tires. It seemed like a drive line issue, however truck is a 2021 model with only 38,000 miles. After I could not find anything out of place I got back on the interstate to see if problems still existed. I was only traveling at 45 mph and vibration was getting worse, so I tried to slow and make it to next offramp when the driver side tire blew out causing me to have to quickly react to prevent having an accident. The tire tread and multiple parts of the truck inner fender guards and liner were thrown out into traffic and truck bed side is badly damaged. Prior to blow out there were no warnings on the dash board to to indicate any sort of issue and I verified tire pressures when I stopped after the vibration initially set in. The TPMS system was working properly at the time of the blowout. I have the tire if further inspection is warranted. My safety was at risk when tire blew out on the interstate along with vehicles traveling around me to avoid hitting the flying debris and tire tread. Further this was driver side tire and I had to change the tire on the side of the interstat