Complaint volume
520 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
520 consumer-submitted complaints on record for the 2021 GMC Sierra, grouped by component category.
520 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 169
POWER TRAIN 64
ENGINE AND ENGINE COOLING 41
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
520 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| Dec 2024 | ELECTRICAL SYSTEM | my truck keeps having this same issue since [XXX], always take it to team Gillman second august 26 same reason they replaced the battery but is a manufacturing defect while i am driving stops out of sudden AND THIS IS THE THIRD TIME THEY SUPPOSED TO CALL ME I HAVENT RECEIVE NO CALL IS AT TEAM GILLMAN SAME REASON ONLY HAS 18000 MILES MY NAME IS [XXX] CELL [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |
| Dec 2024 | ELECTRICAL SYSTEM,LATCHES/LOCKS/LINKAGES | The contact owns a 2021 GMC Sierra 1500. The contact stated while driving at various speeds, the tailgate opened unintendedly. No warning light was illuminated. The vehicle was taken to the dealer but was not diagnosed or repaired. The dealer informed the contact that the VIN was not included in GM Campaign Number: N232426401. The manufacturer was not notified of the failure. The failure mileage was approximately 57,000. | Crash: No Fire: No | 57,000 |
| Dec 2024 | POWER TRAIN,SERVICE BRAKES,ENGINE | I received a notice of a recall for a known problem with GMC transmissions. it is very well known that these transmissions lock up and cause problems with braking and can cause the vehicle to slide off the road when the tires lock up. it also causes hard shifting, which I have experienced. GMC said they will not fix the transmission, they instead will add a device to monitor the transmission, so when the transmission locks up and causes an accident, it will let me know that it was the transmissions fault!!! How is this legal? they will let me know that their transmission caused the accident after the fact? why not fix it? typical of government to do nothing about safety... and instead make laws that allow big corporations and government to make money off of peoples deaths! | Crash: No Fire: No | Unknown |
| Dec 2024 | POWER TRAIN | The contact owns a 2021 GMC Sierra 1500. The contact stated while driving at various speeds and downshifting, the rear wheels locked up with the parking brake warning light flashed on the instrument panel. The vehicle would resume normal operation soon after the failure. The vehicle was taken to a dealer where the contact was informed that there was a pending NHTSA Campaign Number: 24V797000 (Power Train) on the vehicle for the failure. The contact was informed that there was a temporary fix on the vehicle to repair the defect. After the temporary fix was performed, the contact experienced the failure twice within a week. The contact received a call that the permanent fix was available; however, soon after the repair was performed, the failure immediately occurred upon leaving the dealer. The manufacturer was notified of the failure, and the contact was informed that he would receive a callback. The vehicle was not repaired. The failure mileage was approximately 75,000. | Crash: No Fire: No | 75,000 |
| Dec 2024 | LATCHES/LOCKS/LINKAGES | The contact owns a 2021 GMC Sierra 1500. The contact stated while driving 40 MPH, the message that the tailgate was opened was displayed, and the contact became aware that the tailgate had opened. The contact pulled over to the right side of the road to close the tailgate. The vehicle was not taken to an independent mechanic or dealer to be diagnosed or repaired. The contact stated that the VIN was not included in NHTSA Campaign Number: 24V060000 (LATCHES/LOCKS/LINKAGES). The manufacturer was notified of the failure and opened a case and referred the contact to the NHTSA Hotline to report the failure. The failure mileage was 41,000. | Crash: No Fire: No | 41,000 |
| Dec 2024 | POWER TRAIN | The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 24V797000 (POWER TRAIN); however, the part to do the recall repair was unavailable. The local dealer was contacted, and it was confirmed that the part was not yet available. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The contact stated that the transmission was shifting hard while driving. The local dealer was notified of the failure. The cause of the failure was not yet determined. The manufacturer was not made aware of the issue. The failure mileage was 120,000. VIN tool confirms parts not available. | Crash: No Fire: No | 120,000 |
| Dec 2024 | POWER TRAIN | transmission has a shudder when accelerating and after shifting through all gears (8speed) during cruise mode when going on an incline as in overpass it starts to shudder and seems like it is trying to find the right gear to go into . | Crash: No Fire: No | Unknown |
| Dec 2024 | ENGINE | The engine blew up at 67,000 mile while driving down the road. Not sure what happened but there was no warning signs at all. The dealership said they couldn’t know for sure what happened but most likely the oil pump went bad. I have spoken with a few people that have had this same problem with the 6.2 liter engine. It needs to be looked into because this could have caused a major accident on the highway. | Crash: No Fire: No | Unknown |
| Dec 2024 | STEERING,SUSPENSION | Front upper control arm ball joint separated from socket. | Crash: No Fire: No | Unknown |
| Nov 2024 | ELECTRICAL SYSTEM | When accelerating and shifting into drive, the vehicle is experiencing a lag when moving forward. The rear wheels are not latching into the designated gear. When vehicle comes to a complete stop, it will not accelerate and does not want to move. The problem has been reported and there are multiple recalls on similar vehicles of the same make and model. There were no warning symbols or notifications generated at the time of inspection. | Crash: No Fire: No | Unknown |
| Nov 2024 | POWER TRAIN | The contact owns a 2021 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. The contact stated that the rear of the vehicle was shuddering and shaking. The vehicle was not diagnosed or repaired by an independent mechanic or the dealer. The contact stated that over time the failure became more persistent. The contact was concerned because two small children were seated in the rear of the vehicle daily. The manufacturer was made aware of the failure but provided no assistance. The contact referenced NHTSA Campaign Number: 24V797000 (Power Train); however, the contact was informed that the VIN was not included in the recall. The failure mileage was approximately 61,000. | Crash: No Fire: No | 61,000 |
| Nov 2024 | ELECTRICAL SYSTEM | The electronic tailgate switch is malfunctioning and opening on own. We brought in and paid 2 times to have repaired and now the third time has happened. It’s appears this model is recalled in Canada but not US. Why is that when it’s the same parts used and the HD models have also been recalled. Why is our truck not recalled for this? | Crash: No Fire: No | Unknown |
| Nov 2024 | POWER TRAIN | The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 24V797000 (Power Train); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The dealer was contacted. The manufacturer was made aware of the issue. The contact had not experienced a failure. VIN tool confirms parts not available. | Crash: No Fire: No | Unknown |
| Oct 2024 | ENGINE | On memorial day weekend 2023 my truck ,2021 GMC Sierra AT4 was making a awful noise. I pulled over and vehicle died. had it towed and the warranty covered new engine replacement at 54678 miles(large deposit of metal in the oil pan). June of 2024 again, traveling out of town and pickup making terrible noise and shaking at 76651 miles. Replaced lifters in vehicle. October 11, 2024 took vehicle in for oil change, drove 25 miles and vehicle making terrible noise. Pulled over and pickup died. Had it towed to dealer and they are saying it needs a new engine. ( 87000 miles) they are saying its out of warranty. There seems to be a serious problem with this engine( 6.2) in all the research I am finding. I now have a pickup that I am still making payments on , that I cannot drive. | Crash: No Fire: No | Unknown |
| Oct 2024 | ENGINE | The contact owns a 2021 GMC Sierra 1500. The contact stated while driving 45 MPH, there was an abnormal ticking sound coming from the vehicle. The contact stated that several unknown warning lights were illuminated. The vehicle was placed on a trailer and was taken to an independent mechanic who stated that the lifter and cam shaft needed to be replaced. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was contacted and referred the contact to the NHTSA Hotline to report the failure. The failure mileage was approximately 133,000. | Crash: No Fire: No | 133,000 |
| Oct 2024 | STEERING | Getting shift to park safety warning, car is in park, and cannot move at all, Cannot start because vehicle does not believe it is in park. Have been stranded multiple times on this error. | Crash: No Fire: No | Unknown |
| Oct 2024 | ELECTRICAL SYSTEM,UNKNOWN OR OTHER | My vehicle was issued an OTA ( over the air update ) automatically, and the update failed, leaving the screen in my vehicle inoperable, with a message displayed stating " Update failed return to dealer" My vehicles radio/information system is now inoperable. The blue-tooth calling capability is also inoperable. This is a safety issue due to the fact that I am a resident of Minnesota and we have a law that states it is illegal to use your phone while driving. In addition, I am unable to receive severe weather alerts via the radio and do not have the ability to make phone calls in my vehicle in the event of an emergency since it is illegal to use my phone in MN while driving. This is a serious safety hazard The GMC dealer (Mills GMC in Baxter, MN ) that the vehicle is currently at has stated this is not a warrantable repair, even though my vehicle is under warranty. I have also contacted GM service directly and was told they would be willing to offer me "rewards points" There is an active recall for the same issue for other GM models of the same year. Recall # N202319250 Essentially, GM is pushing updates to vehicles without the owners consent, giving the owner no choice but to bring the vehicle to the dealership for a repair which they are calling "wear and tear" This is highly unethical and is making customers vehicles unsafe. | Crash: No Fire: No | Unknown |
| Oct 2024 | ENGINE | Per the dealership: Lifter failure, crankshaft failure, metal shavings in the oil. Complete engine failure. | Crash: No Fire: No | Unknown |
| Sep 2024 | ENGINE | The contact's husband owns a 2021 GMC Sierra 1500. The contact stated that while her husband was driving 80 MPH, the vehicle stalled. Additionally, the "Shift to Neutral and Restart" message blinked. The vehicle was steered to the side of the road where the vehicle failed to restart. The vehicle was towed to an independent mechanic where the failure was not able to be replicated. The vehicle was then towed to the dealer where it was suspected that the crankshaft bearing had seized, putting pressure on the starter, causing a short. The contact was informed that the engine needed to be taken apart for a proper diagnostic test. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 81,000. | Crash: No Fire: No Towed | 81,000 |
| Sep 2024 | POWER TRAIN | The contact owns a 2021 GMC Sierra 1500. The contact stated while driving at various speeds, there was a whining sound coming from the transmission. The vehicle was taken to the local dealer who diagnosed and determined that the transmission was faulty and needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure and informed the contact that the vehicle was not covered under the Extended Warranty for the failure. The failure mileage was 86,000. | Crash: No Fire: No | 86,000 |
| Aug 2024 | STRUCTURE | The contact owned a 2021 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the vehicle was shaking erratically, and the vehicle lost motive power. In addition, the contact stated that an unknown warning light was illuminated. The vehicle was towed to the dealer where it was diagnosed with a fractured front-end frame. The contact was informed that the front-end frame needed to be replaced. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 30,000. | Crash: No Fire: No Towed | 30,000 |
| Aug 2024 | ENGINE | The engine locked up on the truck due to bad lifters. It has the 6.2L engine and after talking to several mechanic shops and research online this is a very common issue. GM is having to put lots of new engine in under warranty due to this issue. They need to have a recall to fix a known issue that is costing people thousands of dollars to replace the whole engine in the truck. We was driving down the hey today and with no working at all the truck died and and would not crank back over. We had the truck towed to a repair shop to find out that our truck had the same issue that lots of people are having and now it’s gonna cost us several thousand dollars to have fixed when realistically GM should be paying to fix this problem. | Crash: No Fire: No | Unknown |
| Aug 2024 | ENGINE | On the evening of 5/6/24, my husband was driving home in our 2021 GMC Sierra 1500 when the truck started to run hard, shaking, and the check engine light came on and was blinking. He pulled onto the side of the road immediately and more messages were coming across the dashboard. The truck was towed to a dealership that same night. Once the dealership assessed what was wrong, we were advised by the dealership who confirmed the lifters failed. The truck is currently still sitting at the dealership as we're waiting for the parts because we've been told multiple times that the parts are on backorder. I understand the truck is available for inspection as its been sitting on the lot since 5/6/24. This is the first time this has happened to the truck, zero prior issues. The truck has great service records and has always been properly maintained. We are currently still under the manufacturer warranty. To date, the dealership is still in possession of the truck for 90 days, and we still do not have any ETA on when the parts will arrive/truck will be fixed. | Crash: No Fire: No | Unknown |
| Jul 2024 | ELECTRICAL SYSTEM | Radio screen will go blank randomly after turning the truck off the I can here the radio but can not see any screen. After turning the radio of an exiting the truck radio still plays all of the sudden the radio will go off and restarting the truck radio is working again .At any random time the radio will go blank again | Crash: No Fire: No | Unknown |
| Jul 2024 | SERVICE BRAKES | While towing a trailer in tow/haul mode on the highway traveling around 60mph, their was a strong downshift clunking sound. About 10 miles later, it happened again, except this time the brakes logged up and truck skid for about a full second and then trailer began fishtailing slightly. Check engine like P2C7A came on. Seems like brakes or transmission momentarily locked up. | Crash: No Fire: No | Unknown |