Complaint volume
484 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
484 consumer-submitted complaints on record for the 2021 GMC Sierra, grouped by component category.
484 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 104 complaints, with an average reported failure mileage of 51,093 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 155
POWER TRAIN 59
ENGINE AND ENGINE COOLING 37
POWER TRAIN,ENGINE 29
ELECTRICAL SYSTEM 26
UNKNOWN OR OTHER 14
STEERING 13
UNKNOWN OR OTHER,ENGINE 12
ELECTRICAL SYSTEM,ENGINE 9
SERVICE BRAKES 9
484 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| 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 | 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 | 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 | 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 | 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 |
| 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 |
| 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 | 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 | 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 | STEERING | The power steering on the truck would quit working at times. I made an appointment with a local dealership to have it checked out. I was told the steering rack was binding and would need to be replaced. I was also told there was a two to four week backorder on the parts. As I am trying to back out of my garage to take it to the dealer the steering totally locked up. I called a wrecker to take the truck to the dealer the next day. When the wrecker operator started to load the truck, at first the steering wheel wouldn't turn . Then it broke lose and worked fine. Imagine if I were driving when this on again off again power steering would quit working!! I should also say this truck only has fifty-seven thousand miles on it. Since there is a backorder on these parts it tells me that I'm not the only one that is having this problem. In my opinion this is a very dangerous safety problem and should be a national recall. Thank you | Crash: No Fire: No | Unknown |
| 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 |
| Dec 2025 | ENGINE | mechanical and electrical issues with my GMC Sierra Elevation Duramax Diesel, purchased in 2021. Despite multiple dealership visits, diagnostic evaluations, repairs, and software updates, these issues persist and have significantly impacted the reliability and safety of the vehicle. In December 2025, my vehicle was taken to the dealership for diagnostics and a third software update intended to resolve recurring engine-related faults. Throughout 2025, the check engine light illuminated on approximately 30 occasions, confirmed by at-home diagnostic scans. The same diagnostic code related to the 1) SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 2 P2C7A - Engine I 2) Exhaust Gas Recirculation (EGR) Cooler Efficiency Below Threshold P14D9 - Engine has appeared repeatedly since the vehicle was first purchased in 2021. Additionally, on approximately 15 occasions in 2025, the vehicle failed to start. When pressing the ignition button, the engine screeched while attempting to turn over for 20 to 45 seconds, after which the vehicle powered off entirely. After waiting approximately 10 minutes, the vehicle would then start normally. Notably, during these no-start events, no check engine light or diagnostic code appeared, and the engine light and starting failure have never occurred simultaneously. hese same concerns were explicitly explained to service technicians during the most recent recall repair in 2025. I was informed that a software update would resolve the issue. However, the problems have continued. A similar frequency of failures occurred throughout 2024. At that time, GMC advised that the issue was likely the vehicle’s battery. Acting on this recommendation, I had the battery replaced at my expense in October 2024 by the dealership. This repair did not resolve the issue. From the time of purchase in 2021 through January 2024, these same symptoms occurred approximately 10 times, demonstrating a long-standing and unresolved defect. | Crash: No Fire: No | Unknown |
| Dec 2025 | ENGINE | Had a "Trans Hot Warning" light. Dealership said it was internal valve body failure. They said there is recall on this for other engine types even though this is same issue. I think GMC needs to expand their recall. | Crash: No Fire: No | Unknown |
| Dec 2025 | ENGINE | The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the engine seized. The contact was unaware of a warning light being illuminated. The contact stated that while attempting to start the vehicle, the vehicle failed to start. The vehicle was towed to the dealer, where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The contact referenced an unknown engine recall; however, the VIN was not under recall. The manufacturer was made aware of the failure, and a case was filed. The contact was advised to report the failure to the NHTSA Hotline. In addition, the contact was informed that the VIN for the vehicle was a Canadian VIN, and the mileage was displayed in kilometers. The failure mileage was approximately 120,000. | Crash: No Fire: No Towed | 120,000 |
| Dec 2025 | ENGINE AND ENGINE COOLING | The contact owns a 2021 GMC Sierra 1500. The contact had received notification of NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling). The vehicle was taken to the dealer where an inspection was performed on the engine. The contact was informed that the vehicle had passed the inspection, and the mechanic added a higher viscosity oil, installed an oil fill cap, replaced the oil filter, and updated the Owner's Manual. The contact stated that the remedy failed to address or repair the possible defect with the engine. The contact stated that the remedy resulted in a higher cost for oil changes, and fuel economy had decreased from 21 miles per gallon to 18 miles per gallon. The manufacturer was made aware of the issue and the contact was provided a case number. The contact stated that the vehicle had not been repaired. The failure mileage was unknown. | Crash: No Fire: No | Unknown |
| Dec 2025 | LANE DEPARTURE | Vehicle experiences a failure to the Lane Departure Warning and Intellibeam headlamps functions, primarily at night. Trouble first began on 3/12/2023 and has been to two GM dealerships for 11 repairs and the problem is still unresolved. GM Executive Escalations have been opened and the problem is still unresolved. Their response is that 18 vehicles experienced this problem and the resolution was to clean the front windshield and update the camera software. This truck has had the camera replaced and software updated three times by two different dealerships. GM is now stating they are unwilling to resolve the problem any further and they would no longer send any Field Engineers to investigate the problem. I have numerous photos, videos and repair logs from with the problem and resolutions performed. Nature of problem: At night, the indicator button for selecting the Lane Departure Warning will go out. If the button is depressed, a message in the DIC indicates Lane Departure Warning Unavailable and there is no way to activate the LDW. It also causes the Intellibeam headlamps to not work. Any help you can provide is greatly appreciated. | Crash: No Fire: No | Unknown |
| Dec 2025 | ELECTRICAL SYSTEM | experience a automatic OTA update to the info system on my 2021 GMC Sierra(I did not iniciate) which burnt out the radio module which controls the info system. I am being charged $1,300+ for repair due to vehicle being out of warranty(52,000 miles) and no recall on this vehicle model for this issue. GMC does have a recall for this exact issue on the 2021 GMC Tahoe models, but not the GMC Sierra. If the GMC utilizes the same componets for both models of vehicle how doe the recall#N202319250 not cover the exact same issue on both models? | Crash: No Fire: No | Unknown |
| Dec 2025 | ENGINE | Heard a ticking noise then check engine light started blinking along with service esc and parking brake. Took it to the dealer and I had a bad lifter again. I was previously repair for lifters under warranty a little over 2 years ago. | Crash: No Fire: No | Unknown |