Complaint volume
517 consumer-submitted complaints are matched to this model year. Treat the count as a research signal, then read the actual summaries for repeated symptoms.
Complaint records
2021 GMC Sierra Complaints
517 consumer-submitted complaints on record for the 2021 GMC Sierra, grouped by component category.
517 Total complaints
5 Crash reports
6 Fire reports
2 Injury reports
Complaint data reflects consumer-submitted reports. A complaint is not proof
of a defect, recall, or manufacturer fault. Enriched severity fields come
from official bulk records when the complaint can be matched by ODI number.
Buyer interpretation
How to use these complaints before buying
Complaint records are most useful when they turn into inspection points, seller questions, and comparison checks against nearby model years.
Pattern to inspect
The most common categories are engine, power train, engine and engine cooling. Use those categories as a test-drive checklist instead of judging the vehicle from the total count alone.
Severity flags
Enriched records include 5 crash reports, 6 fire reports, 2 injury reports, and 0 fatality reports. These fields come from complaint records and should be read in context.
Mileage clue
Mileage is available on 109 complaints, with an average reported failure mileage of 51,910 miles. Compare that with the mileage on the listing.
Questions to ask the seller
- Have you had any problems related to engine, power train, engine and engine cooling?
- Can I see recent maintenance and repair records?
- Has the vehicle ever been towed, involved in a crash, or repaired for the same issue twice?
- Can we also check the recall record for this 2021 GMC Sierra?
Used-car checklist
Use these complaints before the test drive.
Build a buyer checklist to turn these issues into questions and inspection points.
2021 GMC Sierra
Build buyer checklist Compare with other years Sends year, make, and model to pre-fill your checklist.
How severe are the 2021 GMC Sierra complaints?
5 Crash
6 Fire
2 Injury
0 Fatality
30 Towed
3 Medical attention
What are the most common 2021 GMC Sierra complaint categories?
ENGINE 167
POWER TRAIN 64
ENGINE AND ENGINE COOLING 40
POWER TRAIN,ENGINE 29
ELECTRICAL SYSTEM 26
UNKNOWN OR OTHER 16
STEERING 13
UNKNOWN OR OTHER,ENGINE 12
ELECTRICAL SYSTEM,ENGINE 10
SERVICE BRAKES 9
517 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| Jan 2026 | POWER TRAIN,WHEELS | 4 months after bring my truck back to the dealership for a body valve issue on the 10 speed transmission. The truck went into limp mode while I was driving. | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | The oil consumption is abnormal and burns almost 2.5 to 3 quarts between oil changes. This can be a heavy risk to the engine if I don’t check on it every couple weeks. I don’t think after the price I’ve paid for this truck that I should have this concern and this should not be the case | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | 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 | Crash: No Fire: No | Unknown |
| Jan 2026 | POWER TRAIN,ENGINE,FUEL/PROPULSION SYSTEM | On the afternoon of 01/20/26, I was merging onto the highway in my 2021 GMC Sierra 1500 when a loud bang was heard from the engine compartment at approximately 60 mph. Immediately after the ban was heard, several indicator lights on the dashboard were illuminated, including the ESC, check engine light, and parking brake light. A power loss was felt when attempting to accelerate and the banging noise worsened anytime the accelerator was depressed. I was able to drive the vehicle to the nearest GM dealership that coincidentally was at the closest exit off of the highway I was traveling on. The dealership performed diagnostic and determined that the damage was caused due to the ongoing GM recall associated with Safety Recall N252494000. My vehicle had previously been inspected as part of the recall and was found to have passed. Vehicle had been driven approximately 4,000 miles after recall was performed. | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | The engine has a knocking sound. I took it into the dealer and they replaced the exhaust system thinking that was the problem. However, the knocking still happens intermittently. I have video documentation of the noise. | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | For the second time since I have owned the vehicle that was purchased brand new. The engine seized during driving on the highway and began making loud noises that was knocking and jerking the vehicle. The issue occurred initially around 15,000 miles and was diagnosed as lifter failure, was repaired and returned in July 2022. At 64,000 miles on January 15, 2026, while on an interstate the engine did the same thing and the vehicle went into limp mode. It has been diagnosed as lifter failure this second time and is awaiting appropriate repairs. Both incidents put myself in passengers at danger due to the nature in which the vehicle entered limp mode on the highway. | Crash: No Fire: No | Unknown |
| Jan 2026 | POWER TRAIN | 1-At approximately 40,000 miles, my transmission was replaced under warranty. It had been failing since approximately 2000 miles having a very hard time shifting between first and second gear. It was finally replaced at 40,000 miles. 2- At approximately 45,000 miles I took my truck into the dealership for this latest recall on the 6.2 L failure for inspection. Vehicle is inspected and I was told I would need to have an engine replacement. I was told that there was no ETA on when a replacement engine would be available and that I would be contacted when one was. Afterwards I was sent back home in the truck they just inspected for potential engine failure and said had a bad engine. As of now, I’m still waiting on a word of a new engine and my truck is still operating, but leaves me concerned that it could fail at any moment while driving it. | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | There is an active recall for the 6.2 L engines, which is what I have and it’s an issue with burning oil and catastrophic engine failure due to rods and bearings. And I just got this vehicle in November and I have already went through 15 quarts of oil in two months so I’m waiting for my engine to blow up going down the road to cause a wreck like has happened to multiple vehicles already and I also have a rod knock now due to this issue so it could be any time now that my engine fails and I end up getting hurt or my family I took it to the Chevy dealership and I have called GM to do an oil consumption test and to put in a claim so that way if it does fail, then it has paperwork to follow, but it is a major safety concern but something needs to be done considering there’s already 600,000 recalls on this issue already there needs to be more for the rest of the people that are having this issue like myself and I’m spending $50,000 on this truck for the engines to fail and me end up dying before something‘s done. and it’s also very distracting as you’re driving down the road and your vehicle tells you that you’re low on all so you have to try to find a way to get off the highway to have someone bring you all so you can continue to drive and it’s not just a cordial. It is up to 5 quarts of all at a time. | Crash: No Fire: No | Unknown |
| Jan 2026 | ELECTRICAL SYSTEM | Truck went in service 9/17/2025 because the wheels locked up while driving. Transmission was replaced. Picked up truck and 2 hours later the truck shut off while driving and was started back up and was limp mode. Was told wire chaffing and they taped and rerouted wires. Picked truck back up and next day it did the same thing. Took back to the dealer and they said wires again. They taped wires back up and we picked up the truck. We had it 7 days and while driving down the expressway the whole truck shut off and would not start up again. Clearly that is a safety issue. After sitting on the side of the expressway for 10 minutes it started up again and was in limp mode and taken to the dealer again. I don’t know what has been done to it yet as they are not great at communication but they have had our truck for 4 months minus the 7 days we had it before it had to go back to the dealer. | Crash: No Fire: No | Unknown |
| Jan 2026 | STEERING | The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving 5 MPH, the vehicle lost proper steering ability, and the steering wheel became loose and spun around in a circle. The air bag message was later displayed on the instrument panel. Upon inspecting the vehicle, the contact discovered that the bolt connecting the steering shaft was missing. Due to the failure, the vehicle was towed to a dealer, where the cause of the failure was confirmed. The contact was then informed that there were no recalls or warranties on the vehicle. The manufacturer was notified several times about the failure and agreed that the part should never fail. However, the manufacturer then stated that the owner of the vehicle was responsible for the repair. The vehicle remained with the dealer unrepaired. The failure mileage was approximately 80,000. | Crash: No Fire: No Towed | 80,000 |
| Jan 2026 | SERVICE BRAKES | Left rear parking brake actuator malfunction. The truck would brake unexpectedly. The brake would not completely release at times. Took it to the dealer on June 6, 2024 and they replaced the rear rotors and pads. I asked them if the parking brake actuator was faulty and may have caused the premature wear. They laughed and said no, it wasn't possible. On Aug 7, 2024 I returned the truck to the dealer with the fault codes C1114 & C060B caused by a failure of the parking brake actuator. It was impossible to use the emergency brakes when the codes were present. For several months after the repair, brake faults would appear and disappear randomly. Took it to the dealer, and they found nothing wrong. Electric-actuated emergency brakes should be illegal. | Crash: No Fire: No | Unknown |
| Jan 2026 | LANE DEPARTURE,FORWARD COLLISION AVOIDANCE | The front camera stopped working, causing the safety systems to shut off. Codes U026A & U0078 "no communication failure". The camera was ordered and replaced. | Crash: No Fire: No | Unknown |
| Jan 2026 | POWER TRAIN | Unexpected rear wheel lock-up at 29000 miles. While engine braking from highway speed onto an off-ramp at approximately 50 mph, the rear wheels unexpectedly locked up. Due to prior rear brake actuator issues, I suspected the emergency brake had activated without my input. It was only momentary, and no fault codes or warnings were displayed. It happened again under the same circumstances two months later, with no fault codes. On May 9, 2025, the check engine light came on, and I scheduled service. The dealer addressed a recall regarding the transmission by installing software. In August 2025, I received a letter from GM regarding recall N242454440 for excessive wear in the transmission control valve, which was causing rear-wheel lockup. On October 31, 2025, while towing a small enclosed trailer at 70 mph on the highway with cruise control engaged, the truck suddenly decelerated, and I was nearly rear-ended by a semi-truck (no brake lights to warn them). The truck would not go over 50 mph unless I was going downhill. The transmission would not shift into higher gears. I returned it to the dealer, who checked the computer and found no record of the incident, so they said there was no problem. They informed me that the new software was designed to limit the truck's speed if a potential lockup was detected. This recall did not fix the transmission problem or the safety issue. It was simply a way to avoid costly repairs. There is a problem with the physical transmission valve that, for me, resulted in an extremely dangerous situation. The NHTSA needs to take this issue seriously and require GM to replace the prematurely worn valves in the affected vehicles. | Crash: No Fire: No | Unknown |
| Jan 2026 | ELECTRICAL SYSTEM | Muti pro tailgate has electric issues due to moisture. Tailgate will open up driving down the road. | Crash: No Fire: No | Unknown |
| Jan 2026 | FUEL SYSTEM, GASOLINE,ENGINE | The contact owns a 2021 GMC Sierra 1500. The contact stated that after driving on a trip, the contact noticed that the vehicle had lost 10 MPG after a software update was performed. The check engine warning light was illuminated. The vehicle was taken to Richardson Chevrolet (3825 S Huron Rd, Standish, MI 48658), who confirmed that the vehicle was working as designed. The check engine warning light was reset. The vehicle was not diagnosed or repaired. The manufacturer was contacted and opened a case, and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 57,000. | Crash: No Fire: No | 57,000 |
| Jan 2026 | ENGINE | 2021 gmc purchased brand new Truck had complete engine failure lifters and rods were replaced at 7000 miles under factory warranty lost complete engine power GMC says we are not on any recall and they refused to buy back the truck or give me an extended warranty they said this year 2021 with 5.3 doesn’t have engine issues. | Crash: No Fire: No | Unknown |
| Jan 2026 | POWER TRAIN,ENGINE | I own a 2021 GMC Sierra 1500 equipped with the 6.2L L87 V8 engine and 10-speed transmission. The vehicle exhibits the following issues: Persistent lifter ticking noise audible from the driver-side wheel well, even when the engine is warm. Rough idle that is noticeable at stops and low-speed conditions. Transmission shifting problems, specifically harsh or delayed shifts when downshifting from 3rd to 2nd gear during deceleration. These symptoms raise concerns about potential lifter failure and transmission defects. I am aware of GM’s recall (25V-274) and NHTSA Engineering Analysis EA25007, but my vehicle’s build date (January 2021) currently falls outside the official recall window. Given the similarity of symptoms to those under investigation, I believe my vehicle may be affected by the same defect. Safety Concern: The rough idle and shifting hesitation could lead to unexpected loss of power or unsafe driving conditions, especially during deceleration or merging. Request: Please include this complaint in EA25007 and consider expanding the recall to cover earlier builds. I am willing to provide service records, videos, and additional documentation upon request. | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | Motor was chugging took to a dealership on march 22 was told I had a collapsed lifter I was told my cost would be 4800 gm would cover half which was fine then when the work was done the dealership took it for a test drive while they were on the test drive the motor locked up they originally told me it was a cam bearing later I found out through paperwork that was emailed to me that it was a main bearing which is consistent with the recall but my vin number hasn’t came up it’s a 2021 gmc sierra 1500 with a l87 6.2 and it cost me 6200 I was 10,000 miles out of warranty | Crash: No Fire: No | Unknown |
| Dec 2025 | ENGINE | Faulty lifters replaced on passenger side. Had only 25000 miles on engine. GM extended warranty on thousands with this engine but not mine. Have only 28000 miles on truck and just turned 5th year so warranty is void. GM should extend warranty on all vehicles with this engine. | Crash: No Fire: No | Unknown |
| Dec 2025 | ELECTRICAL SYSTEM | The Intermediate speed sensor 2 and internal transmission harness failed. The repair was to replace the internal transmission harness and intermediate speed sensor. This vehicle is a 2021 and I was told this was recalled on a 2022 only. | Crash: No Fire: No | Unknown |
| Dec 2025 | ENGINE | TRAVELING ON INTERSTATE GOING AT THE POSTED SPEED LIMIT AND TURNED OFF THE INTERSTATE ONTO MY EXIT TURN AND VEHICLE ENGINE STARTED KNOCKING AND ENGINE SHUT OFF OIL WARNING LIGHT CAME ON ALL WHILE TRYING TO STOP THE VEHICLE AT THE CROSS TRAFFICE STOP SIGHN AND ENDED UP STOPPED IN THE MIDDLE OF ANOTHER HIGHWAY BARLEY MISSING THE CROSS TRAFFIC COMING AT ME FROM BOTH DIRECTIONS. THIS HAPPENED AT I94 AND COUNTY HIGHWAY 34 AT BARNESVILLE MINNESOTA EXIT. THIS SUDDEN ENGINE FAILURE NEARLY KILLED ME AND THE 2 VEHICLE DRIVERS THAT NEARLY STRUCK MY TRUCK FROM BOTH DIRECTIONS. GMC WOULD NOT HELP ME WITH MY REPAIR OF OVER $11000.00 DOLLARS FOR A NEW CRATE MOTOR FROM GMC. SITING MY TRUCK DID NOT FALL UNDER THE L87 RECALL. FAILURE ROD BEARINGS AND CRANK BEARINGS WITH A TON METAL SHAVINGS IN THE OIL AND FILTER. NO WARNING THIS WAS GOING TO HAPPEN. MY TRUCK HAD 95000 MILES ON IT WHEN IT NEARLY KILLED ME AND OTHERS. INDEPENDENT SERVICE CENTER JOHNSONS AUTO REPAIR IN MOORHEAD MN INSTALLED THE NEW CRATE MOTOR FROM LUTHER GMC FARGO ND. | Crash: No Fire: No | Unknown |
| Dec 2025 | ENGINE | Complete engine power loss. | Crash: No Fire: No | Unknown |
| Dec 2025 | POWER TRAIN,FUEL/PROPULSION SYSTEM | Transmission valvebody failure, causing rapid, repeated rear wheel lock ups. Videos can be provided. These happen almost daily at highway speeds. This will cause a very bad accident | Crash: No Fire: No | Unknown |
| Dec 2025 | LATCHES/LOCKS/LINKAGES | The contact owns a 2021 GMC Sierra 1500. The contact stated that after the vehicle was taken to a local car wash, upon further inspection, the tailgate door had independently unlatched and was open. No warning light was illuminated. In addition, the contact stated that while driving at an undisclosed speed, the local Police Department called about luggage found on the side of the road. Upon further inspection, the contact noticed that the tailgate had independently unlatched and was open. The vehicle was previously taken to a local dealer, where the vehicle was repaired under warranty. The vehicle was taken back to the same local dealer where it was repaired for a tailgate switch failure at the owner's expense. The manufacturer was made aware of the failure. The failure mileage was approximately 30,000. | Crash: No Fire: No | 30,000 |
| Dec 2025 | UNKNOWN OR OTHER,ENGINE | The coolant control valve has failed on two occasions—once during the warranty period and again approximately 18 months later, outside of warranty. Each failure resulted in continuous fan operation and fluctuating engine temperatures. Failed on around June 2024 and again December 17, 2025 | Crash: No Fire: No | Unknown |