2021 GMC Sierra 1500

577 complaints on file, page 1 of 29.

1. Filed Oct 1, 2026Failure Feb 2, 2026Richmond, INElectrical system, Engine, Power train

   Received Re-Call for Engine Failure! Dealer replaced Engine Oil and Oil Cap @ 85,544 Miles. I read of the Re-call prior to the notice and I waited for it to come. After I received it and the Dealer made the changes, it made me afraid to leave town using my truck for fear of a breakdown on the Freeway. I use a Walker, so if I broke down and I was in the left lane and lost all power it would be very dangerous for me to get to the right side of the road! The truck started using excessive Oil after they changed the oil. I replaced four (4) quarts of oil @ 2526 miles! Speedometer reading 88070 miles.

   NHTSA complaint 11768259
2. Filed Oct 1, 2026Failure Sep 7, 2026Atwater, CAEngine, Fuel/propulsion system, Power train

   1. I am being told that the high-pressure fuel pump (HPFP) catastrophically seized and locked up internally while driving. Because the HPFP on the 3.0L Duramax (LM2) engine is directly driven by the engine's timing system, this sudden mechanical seizure instantly destroyed the engine timing gears and snapped/skipped the timing chain. The failed components are currently intact inside the vehicle and are fully available for inspection upon request at Ron's Smith GMC in Merced, CA. 2. The failure occurred on busy Labor Day (XXX) while our family of [XXX] was traveling back home at 70 mph on a major highway. The truck violently shook, instantly lost all engine power, and forced the vehicle into a dangerous limp-mode state before completely stalling in live highway traffic at night around 10:45 pm. This sudden loss of propulsion at high speed severely compromised our ability to safely navigate out of the way of fast-moving highway traffic, creating an immediate & extreme risk of a high-speed rear-end collision. At times hazard lights didn't work causing family panic & screaming as truck shook with passing traffic. 3. The problem has been officially confirmed by Ron Smith GMC in Merced, CA. Their service department diagnosed the issue, confirming that the high-pressure fuel pump had locked up and subsequently destroyed the timing belt/chain & engine gears. 4. The vehicle and its failed components have only been inspected by technicians at the Ron Smith GMC dealership service department. No police, insurance representatives, or outside third parties have inspected the vehicle yet. 5. I had been extremely happy with my truck and there were absolutely no warning lamps, dashboard messages, or driving symptoms prior to the failure. The truck was operating perfectly normally under cruise until the exact moment of the failure, at which point a "Reduced Engine Power" warning flashed on the dashboard simultaneously with the mechanical lock-up, shaking, and immediate stall. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF

   NHTSA complaint 11768206
3. Filed Sep 30, 2026Failure Sep 7, 2026Atwater, CAEngine, Fuel/propulsion system, Power train

   1. I am being told that the high-pressure fuel pump (HPFP) catastrophically seized and locked up internally while driving. Because the HPFP on the 3.0L Duramax (LM2) engine is directly driven by the engine's timing system, this sudden mechanical seizure instantly destroyed the engine timing gears and snapped/skipped the timing chain. The failed components are currently intact inside the vehicle and are fully available for inspection upon request at Ron’s Smith GMC in Merced, CA. 2. The failure occurred on busy Labor Day (XXX) while our family of [XXX] was traveling back home at 70 mph on a major highway. The truck violently shook, instantly lost all engine power, and forced the vehicle into a dangerous limp-mode state before completely stalling in live highway traffic at night around 10:45 pm. This sudden loss of propulsion at high speed severely compromised our ability to safely navigate out of the way of fast-moving highway traffic, creating an immediate & extreme risk of a high-speed rear-end collision. At times hazard lights didn’t work causing family panic & screaming as truck shook with passing traffic. 3. The problem has been officially confirmed by Ron Smith GMC in Merced, CA. Their service department diagnosed the issue, confirming that the high-pressure fuel pump had locked up and subsequently destroyed the timing belt/chain and engine gears. 4. The vehicle and its failed components have only been inspected by technicians at the Ron Smith GMC dealership service department. No police, insurance representatives, or outside third parties have inspected the vehicle yet. 5. I had been extremely happy with my truck and there were absolutely no warning lamps, dashboard messages, or driving symptoms prior to the failure. The truck was operating perfectly normally under cruise until the exact moment of the failure, at which point a "Reduced Engine Power" warning flashed on the dashboard simultaneously with the mechanical lock-up, shaking, and immediate stall. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF

   NHTSA complaint 11768204
4. Filed Sep 30, 2026Failure Sep 16, 2026Pella, IAEngine

   There is an known issue with the coolant control valve that causes the truck to enter "limp mode" that dangerously reduces the engine power. The part is not recalled but there is a special extended warranty, N252508341, up to 15yrs or 150,000 miles for 2021-2022 GMC 1500 trucks but my VIN is excluded from this for some reason. I would like this investigated.

   NHTSA complaint 11768124
5. Filed Sep 28, 2026Failure Sep 28, 202698,000 milesCedar Point, OKElectrical system, Engine1 injured

   The contact owns a 2021 GMC Sierra 1500. The contact stated that while the vehicle was parked, the battery charge indicator to zero. The vehicle lost motive power, and the vehicle was unable to exceed 30 MPH while driving. The vehicle was driven in LIMP Mode. The battery saver mode message was displayed before and during the failure. The vehicle then failed to restart. The vehicle had been repaired a year prior to the failure. The contact's blood pressure became elevated due to the issue. The failure mileage was approximately 98,000.

   NHTSA complaint 11767454
6. Filed Sep 28, 2026Failure Sep 28, 2026Oswego, NYPower train

   The transmission overheats on this vehicle shutting the vehicle into “limp mode” this is extremely dangerous when at interstate/highway speeds and the vehicle slows it self down to a dangerously low speed and all other vehicles around are traveling at a high rate of speed, this has happened twice, it has also happened while in back roads and tractor trailers have had to swerve to avoid a collision.

   NHTSA complaint 11767398
7. Filed Sep 26, 2026Failure Sep 26, 2026Grovetown, GAEngine

   Excessive oil consumption. I am fearful that my vehicle engine will lock up.

   NHTSA complaint 11767091
8. Filed Sep 24, 2026Failure Aug 18, 2026Moreno Valley, CAPower train

   I own a 2021 GMC Sierra 1500 AT4 with the 3.0L Duramax diesel. The vehicle developed severe transmission problems, including harsh/jerky shifting and a hard clunk when shifting into reverse. The vehicle was subsequently diagnosed with an internal transmission failure. The repair facility informed me that the transmission gears had failed and caused damage to the transmission and stated that the failure appeared to be related to a manufacturing issue. The repair facility also advised me to watch for a future recall because they believed this could be a widespread issue occurring in other vehicles. I am submitting this complaint so the failure can be documented and considered along with other reports of transmission failures involving this vehicle.NOTE FROM AUTOSHOP:TRANSMISSION FAILURE WAS DUE TO A MANUFACTURE DESIGN FLAW, NOT DUE TO THE CUSTOMER'S DRIVING HABITS. THE PUMP ORIGINAL DESIGN IS WITH SLANTED GEARS AND THE GEARS ARE FORCED AWAY FROM EACH OTHER AND PLACING TOO MUCH STRAIN THE BEARINGS ANI THE BEARING FAIL. AN UPDATE PERFORMED TO HAVE STRAIGHT CUT PUMP GEARS TO AVOID BEARING DAMAGE. CDF DRUM AND CENTER SUPPORT CHANGED TO UPDATED PARTS THAT ARE HEATED TREATED TO AVOID DAMAGE

   NHTSA complaint 11766718
9. Filed Sep 23, 2026Failure Aug 10, 2026Marshall, MOPower train

   Purchased a used 2021GMC SIERRA in Mar. 2025 from W&K GMC Sedalia Mo. Two mths ago ([XXX]) noticed an occasional slipping in transmission, wheels lock up. The truck would slip, lock for 1-4 seconds and then return back to normal driving. Has done this while accelorating and while driving down the highway. I took truck to my local repair garage who indicated it was most likely the torque converter and it would need to be taken to the dealership for repair. After mechanic commenting that he had seen several GMCs with the same problem, I looked up GMC recall and found that this issue did have a recall on 2020 - 2022 GMC SIERRA TRUCKS ( ours is a 2021)! When my VIN did NOT show any recalls, I called W& K GMC in Sedalia on 9-23-26 and spoke with the shop who told me MY truck did not have the recall notice and it would cost me $160 out of pocket for a diagnostics and $600 -$800 for a converter to even be flushed to see if problem resolved PRIOR to any part replacement. They would have to charge me full price for this repair since MY VIN DID NOT HAVE A RECALL, BUT THE SAME TRUCK MODEL, YEAR, AND ENGINE HAS OTHER RECALLS? I called GMC customer service line on 9-23-26, spoke with customer service agent Tanika, she documented the same info. and could not explain why a 2021 Sierra with the same problem as a 2020-2022 Sierra was not included in this recall that it must have been manufactured in a different facility? The fact that my local garage mechanic in a very small town, has already seen SEVERAL GMC trucks with the SAME PROBLEM, leads me to believe this is a WIDE SPREAD PROBLEM, that GMC is choosing to ignore due to the cost of repairs involved. I am requesting an investigation into HOW MANY RECALLS HAS GMC SENT OUT AND REPAIRED? AND SPECIFICALLY WHY AFTER 3 YRS OF PRODUCTION BY GMC DO THEY BELIEVE A TRANSMISSION PROBLEM WAS ONLY CERTAIN VEHICLES AND NOT ALL THE VEHICLES? This is a huge safety concern if wheels lock up on hwy at 70mph due to malfunctioning TC INFORMATION REDACTED PURSUANT TO THE FREEDOM OF I

   NHTSA complaint 11766353
10. Filed Sep 22, 2026Failure Sep 21, 2026Semora, NCEngine, Fuel/propulsion system

    On [XXX], my vehicle suffered a complete loss of propulsion on the highway, displaying fault codes P0324 and P0016. The vehicle was taken to Boyd's Tar Heel Chevrolet in Roxboro, NC, where the engine block was replaced under the official GM 6.2L engine safety recall.The truck was delivered back to me, and on the very first day I drove it—only 28 miles from my house—it suffered a secondary catastrophic loss of propulsion on the highway on [XXX]. The check engine light began flashing violently, indicating an immediate catalyst-damaging safety hazard, and the vehicle displayed fault code P0307 (Cylinder 7 Misfire).The dealership explicitly instructed me to stop driving the vehicle immediately, authorized the recovery, and told me to bill the tow directly to them. After towing the vehicle back to their facility, Boyd's Tar Heel Chevrolet reversed their position. They are now attempting to hold me financially responsible for the towing fees, along with spark plugs, wiring, and fuel injector services, claiming the failure is due to routine maintenance.This represents a severe highway safety hazard, a direct failure of the manufacturer's official recall remedy, and potential dealer misconduct to avoid liability under the active NHTSA Engineering Analysis EA26005 for post-recall 6.2L engine failures. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

    NHTSA complaint 11766062
11. Filed Sep 18, 2026Failure Sep 15, 2026Salem, ALEngine

    While driving 40 MPH my entire dash lite up with every known light and the vehicle lost all power. The dealer stated I need an entire engine replacement, as with Many 6.2. My vehicle is 1 months out side of the recall, it has the exact symptoms and the exact damage as the recall.

    NHTSA complaint 11765344
12. Filed Sep 18, 2026Failure Jul 20, 2026Springville, UTEngine, Suspension

    Both of my upper ball joints wore out and one broke as I was driving down the road at 65 miles an hour pulling me into the on coming lane of traffic, there was no warning of this. I had both upper and lower ball joint replace. If there had been another vehicle coming in the on coming lane we would have had a head on collision. At an earlier date the motor in this same truck had a fallen lifter which cause my motor to loss power, I was able to take it to the local GM dealer and they fixed it, there was no warning this was happening either. I am worried I will have a catastrophic engine failure and GM will not cover this. I have looked up my

    NHTSA complaint 11765281
13. Filed Sep 17, 2026Failure Jul 22, 2026EL Cajon, CAUnknown or other

    NUMERO DE VIN FALTANTE

    NHTSA complaint 11764993
14. Filed Sep 16, 2026Failure Sep 9, 202666,000 milesLanesboro, MNLatch

    The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at various speeds, the tailgate opened independently. The failure occurred several times and became more persistent recently. The contact stated that while the vehicle was parked in the driveway, the side marker lights started flashing, and the tailgate opened. Additionally, upon exiting a store, the contact discovered that the tailgate had opened while the vehicle was parked. The dealer and the manufacturer were notified of the failure and confirmed that the VIN was not included in a recall. The failure mileage was approximately 66,000.

    NHTSA complaint 11764674
15. Filed Sep 15, 2026Failure Aug 20, 2026Clarksville, TXElectrical system, Vehicle speed control

    Dashboard keeps returning to aljarir type writing. We bought it with American English but won't stay in English. Monday will be 30 day and I believe the dealer is ghosting me. Y'all have any ideas how to reset the dashboard without replacing the radio??? Closest answer I was given.

    NHTSA complaint 11764558
16. Filed Sep 14, 2026Failure Sep 12, 202694,328 milesGastonia, NCEngine and engine cooling

    The contact owns at 2021 GMC Sierra 1500. The contact stated that while driving 60 MPH, the engine was overheating. The message "Reduce Engine Power" was displayed. The contact shifted to neutral to reach the dealer. The contact associated the failure with Special Coverage: N252508341; however, the VIN was not included. The dealer diagnosed the vehicle with coolant control valve failure, and the vehicle was repaired. The manufacturer was made aware of the failure and stated that the cost of the repair was not covered under the special coverage program. The failure mileage was approximately 94,328.

    NHTSA complaint 11764209
17. Filed Sep 11, 2026Failure Aug 24, 2026Pingree Grove, ILEngine

    Check engine light came on my vehicle (104,000/mi) and fans came on while truck was off. Took to dealership and techs diagnosed vehicle as having bad "coolant flow control valve". Dealership ran VIN check as there is a GM "extended special coverage program" N252508341 for the LM2 motor, which my vehicle has. However, N252508341 only applies to vehicles in CA. The dealership did not cover my repair. I filed a complaint with GM who denied it due to the program being only applicable to CA trucks. I was advised to file a complaint with NHTSA as the only avenue with recourse. I would like if NHTSA intervened and made GM honor the program in all 50 states and I be offered a refund for the $2500.00 repair I had to pay for. Thank you.

    NHTSA complaint 11763611
18. Filed Sep 10, 2026Failure Sep 10, 2026Katy, TXUnknown or other

    The engine coolant control valve on my 2021 GMC Sierra 3.0L Duramax diesel failed. This specific component failure triggers an active vehicle 'No-Restart' safety event during automatic engine stop/start operations (per GM Service Bulletin #24-NA-070). This condition can suddenly prevent the vehicle from restarting when stopped at intersections or in active traffic, creating an immediate highway safety hazard and leaving the vehicle stranded. Additionally, the vehicle's radiator cooling fans run continuously at 100% maximum capacity as a system fail-safe, creating severe electrical drain. General Motors has issued a Special Coverage Adjustment (#N252508341) acknowledging the high failure rate of this part, but it is capped at 150,000 miles. Because this defect causes unexpected stalling/no-start safety risks in live traffic past this arbitrary mileage limit, a formal safety recall is required.

    NHTSA complaint 11763419
19. Filed Sep 10, 2026Failure Jun 14, 2026Meridian, IDEngine

    Engine stop working, lots of black smokes through the exhausts and vibrating weird. Lifters failed amoung other parts and they deemed the engine bad so they replaced it with a new one. The new engine started to make the same weird noises.

    NHTSA complaint 11763347
20. Filed Sep 9, 2026Failure Sep 8, 2026Hamilton, GAEngine

    Catastrophic engine failure at 77357 miles. I went to the local GM dealer and my VIN is not in the L87 engine recall. Not sure how to repair my truck , but feel like the engine should not have locked up with such low miles, and I done constant engine maintenance , meaning oil changes every 5K miles.

    NHTSA complaint 11763146