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 |
|---|---|---|---|---|
| Jul 2024 | LATCHES/LOCKS/LINKAGES | The contact owns a 2021 GMC Sierra 1500. The contact stated while the vehicle was parked and turned off, the electronic rear tailgate door erroneously unlatched and opened. The contact stated that the failure had occurred on several occasions. The cause of the failure was not yet determined. The local dealer and manufacturer were notified of the failure. The failure mileage was 58,000. | Crash: No Fire: No | 58,000 |
| Jun 2024 | UNKNOWN OR OTHER | The transmission/torque converter is causing (bucking, kicking, jerking, slipping, difficulty when taking off, shuddering during driving, fishbite, and chuggle). Its becoming a safety hazard now because its putting me and others at risk for an accident. The vehicle will hesitate to go in which if traffic may be rear ended by another vehicle. During weather/rain the vehicle will lose traction and the rear wheels will spin causing an accident. Problem has been reported to dealership multiple times and the only solution they can provide is keep driving the vehicle. Vehicle has no warning lights at all or any other symptoms of problems prior to when the components started to fail. The issue first happened around February 2024 and remains to be an issue to this present day. I've been the dealership more than 6 times with no solution/fix. I'm concerned for my safety now and need this issue addressed ASAP. | Crash: No Fire: No | Unknown |
| Jun 2024 | STRUCTURE,LATCHES/LOCKS/LINKAGES | The contact owns a 2021 GMC Sierra 1500. The contact stated that the inner tailgate door failed to open while pressing the release button. On several occasions while pressing the release button, the inner door would lower down. The cause of the failure was not yet determined. The manufacturer and local dealer were notified of the failure, but no assistance was provided. The failure mileage was 45,000. | Crash: No Fire: No | 45,000 |
| Jun 2024 | UNKNOWN OR OTHER,ENGINE | On [XXX] at approximately 3 pm I left my house and was traveling on [XXX] in Fort Mohave Arizona I was only traveling 7 miles. When I looked at the temperature in the cab was 121 degrees a few moments after the display system went black and never turned back on. I arrived at the store 4 minutes after the display shut off with no warning lights or any type of notification on my phone, I had rolled down the windows to get air in the cab to see if that would help cool down if needed. I was in the store 20 minutes. I returned to the truck turned it on and everything was normal, from there I drove back home nothing happened on my drive back the display was working. At 8 30pm I was traveling on [XXX] Driving towards a casino called Avi. I had the driver's side window halfway down when I smelled a faint plastic burn thinking it was coming from the outside because I had the window halfway down. That is when the cab of the GMC filled up with smoke that came in thru the air vents and flames started to show coming from the defrost vents and under the hood while I was driving. I had to stick my head out of the window to see where I could pull over without starting a huge brush fire. As I pulled over and the truck within seconds fully ignited into flames. Enough time to grab my belongings that I was able to save. My life was at risk by this vehicle igniting while I was driving. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: Yes | Unknown |
| Jun 2024 | ELECTRICAL SYSTEM | The inner tailgate continually releases the upper tailgate, which then opens when the vehicle is driven. When latched, the tailgate immediately opens again. This is reproducible. I gather the switch is shorted closed, leading to the release of the tailgate. This poses a risk to items in the bed of the truck leaving the vehicle unexpectedly while in motion. The truck has not been to the dealer yet, there has been no inspection of the vehicle by any authority. The vehicle displays a warning “inner tailgate open.” | Crash: No Fire: No | Unknown |
| Jun 2024 | ENGINE | The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle failed to accelerate as needed and made an abnormal sound. The contact assumed that the sound was coming from the transmission and the vehicle was taken to a dealer. The dealer diagnosed the vehicle and suggested that the failure might be a pulley or a rod bearing failure. The contact took the vehicle to another dealer who confirmed a rod bearing failure. The manufacturer was not made aware of the failure. The vehicle was not repaired. The failure mileage was approximately 46,000. | Crash: No Fire: No | 46,000 |
| May 2024 | LANE DEPARTURE,BACK OVER PREVENTION,FORWARD COLLISION AVOIDANCE | I am writing to complain about that General Motors has issued a retrofit program for 2022 model vehicles that did not come with safety features due to the microchip shortage. I purchased my vehicle new in 2021 and the vehicle did not have the option of having safety features at the time of purchase. I find not having the safety features in a large vehicle to be a safety concern for those that use the vehicle or around the vehicle. General Motors should add the 2021 model vehicles that also did not have the ability to have those features on them added as a part of their retrofit program. | Crash: No Fire: No | Unknown |
| May 2024 | VISIBILITY/WIPER | The wiper blade motor is defective. While driving during a storm the wiper blade motor stopped working on the delayed and low settings. This was a safety issue while driving. I took my vehicle to get looked at a GM Dealer to look at the vehicle. My vehicle is only 3 years old and should not have issues with the wiper blade motor. | Crash: No Fire: No | Unknown |
| May 2024 | STEERING | I just purchased a used 2021 GMC Sierra after having for a month the SERVICE POWER STEERING came on, I took it in for service and was told the part is on back order. Not to worried if the dealership and GM sold it to me that way. I am going to drive it and hope and pray that nothing bad happens. And if it does i will be getting a Lawyer. | Crash: No Fire: No | Unknown |
| May 2024 | SUSPENSION | The contact owns a 2021 GMC Sierra 1500. The contact stated while driving 40 MPH, the front driver's side wheel separated and fell underneath the front end of the vehicle, causing the vehicle to veer towards oncoming traffic. The contact was able to pull to the side of the road, where the vehicle was awaiting to be towed. The contact related the failure to NHTSA Campaign Number: 21V718000 (Suspension); however, the VIN was not included. The dealer was notified of the failure. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was 37,470. | Crash: No Fire: No | 37,470 |
| May 2024 | ENGINE | The coolant control valve is faulty and needs to be replaced. GMC and the dealership know about the issue (Bulletin No. PIP5791), but are not fixing it in a timely manner. This is a safety concern as the system will automatically reduce engine power, which is a major concern when towing and/or in mountainous terrain. | Crash: No Fire: No | Unknown |
| May 2024 | ELECTRICAL SYSTEM,ENGINE | The component that has failed is the engine coolant flow control valve AC Delco part number 55516369. Unfortunately the part is still installed on the vehicle. It has been taken to a dealer and this is a known issue but no recall has been issued. The check engine comes on sometimes but not always, sometimes the pickup has plenty of power to drive and sometime it will barely pull itself, all in the same trip without shutting the ignition off. The symptoms first started in December of 2023, but were sporadic, now it is nearly everytime the pickup is started. It is extremely dangerous to drive this vehicle when it has a problem. You cannot tell if it will accelerate normally or is you will push the pedal and it does nothing. The part to repair the problem is on backorder and no release date is yet available. We have been waiting for 3 months and still no word on when this will be repaired. | Crash: No Fire: No | Unknown |
| May 2024 | ELECTRICAL SYSTEM,SERVICE BRAKES | My truck had smoke rolling out at work when I noticed it. Tried to put it out it Burnt my hands ! destroyed the inside I had it towed and insurance investigator said it was do to a brake controller for the trailer. And I took it to get estimate and the service dept said it was do To brake controller my truck was totaled my wallet toast my coat was toast my I phone my deposit my truck i drove daily to work out of and personal. General Motors would not help I called the. First. Then I was frustrated called my insurance they started a claim and low balled me now I lost 2 months of work bills stacked and low ball price on what the offer was) and haven’t gotten one yet. Called gm back they said I had an active claim they woundenr help it’s there defect I lost my job my mind etc on this. Two investigators state the same thing even there service dept. A gm service dept said the same thing. No warning indicators at al I will never buy another truck. The safety issue is people driving around not knowing. The 2500 and 3500 have them. Looked it up the plant that made my truck left the parts for manufacturing outdoors they got wet. It’s on the internet people r gionbg to get hurt. Lucky I was outside when my was on fire. Please help on the matter. Thank u | Crash: No Fire: Yes | Unknown |
| Apr 2024 | ELECTRICAL SYSTEM | Tail gate failing from water intrusion. Wont stay up while driving. Already a recall for it in Canada but nothing in the USA where i see others have the same problem | Crash: No Fire: No | Unknown |
| Apr 2024 | STRUCTURE | The contact owns a 2021 GMC Sierra 1500. The contact stated that there was water leaking through the rear sliding window. The dealer was notified of the failure and advised the contact that a fee would be charged for the repair. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was approximately 51,000. | Crash: No Fire: No | 51,000 |
| Apr 2024 | ELECTRICAL SYSTEM,STRUCTURE | Tailgate drops without warning, lower button on tailgate doesn't work. | Crash: No Fire: No | Unknown |
| Mar 2024 | STRUCTURE | I have a 2021 GMC Sierra 1500 with a power 6-point tailgate. The inner tailgate has been spontaneously opening for some reason. It seems the electric lock mechanism trips. This could case the contents of my truck bed to fall out. This issue is a known issue for GMC Sierras and a recall has been issued for the 2500's and 3500's but for some reason not the 1500's even though the tailgate is the exact same. I have an appointment to have the issue serviced at dealership, but since there is no current recall they will not cover the expense. | Crash: No Fire: No | Unknown |
| Mar 2024 | ENGINE AND ENGINE COOLING | The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at approximately 75 MPH and depressing the accelerator pedal, the vehicle failed to accelerate as intended. The check engine warning light was illuminated. The contact stated that the vehicle would slow down as if it was losing motive power. The vehicle was driven to a local dealer where it was diagnosed that the coolant control valve needed to be replaced. The vehicle was not repaired due to parts not being available. The manufacturer was notified of the failure. The failure mileage was approximately 32,000. | Crash: No Fire: No | 32,000 |
| Mar 2024 | STRUCTURE | GMC1500 Sierra pick up truck. Rear tailgate dropped today, 3.15.2024. Weather was rainy, tailgate was up at the start of the trip. Contacted GM Corp and was told this model 1500 was not part of the recall?? | Crash: No Fire: No | Unknown |
| Mar 2024 | STEERING | Alignment Cam Guide Pins sheared off while driving on highway. Alignment went all over the place and car was drifting side to side. Also, steering wheel spun a quarter turn while car was not turning but still driving on highway. Almost caused me to crash. GMC does not want to acknowledge the issue or allow me to file a warranty claim. Car could not be driven to GM dealership safely and had to be repaired at closest shop | Crash: No Fire: No | Unknown |
| Mar 2024 | ELECTRICAL SYSTEM | It started year and a half ago involving my tailgate. The buttons to operate by upper and lower tailgate failed to operate on the rear of the truck, but cab button and remote button would open the full tailgate. Returned truck to dealer and they replaced the rear control. It worked for approximate 4 or 5 months the the total tailgate button failed, half tailgate button worked no problem. About 6 mths ago I went to drive to work and hit a bump felt like something bounced but really didn't think of tailgate being open. Drove on interstate for 7 miles at speed of 70 to 75 mph. I had my structural firefighting equip in the bed. Stopped at a drive thru for coffee then drove 5 miles to other side of town to my workplace put truck in reverse and my camera showed the ground, my tailgate was open. Thank goodness nothing fell out of the bed. 2-3 days later left for work, hit bump and felt the rattle in the rear again, stopped and tailgate down, closed tailgate and it opened again immediate after closing. This has occurred numerous times, now the half gate now unmatched along with entire tailgate and opens hitting hitch, scratched paint off. Thought it was me hitting keys in my pocket but continued to occur with key in cab. My mileage warranty passed so I was waiting to get some extra cash to fix the tailgate latches. Have not seen any recalls for GMC sierra 1500 denali, thought I would file a "complaint". | Crash: No Fire: No | Unknown |
| Mar 2024 | ELECTRICAL SYSTEM | While driving down the road at random times of the day, random days, random drive periods, random locations, the DIC and touch screen along with radio will shutdown and restart, like rebooting the system or just starting the truck. I loose the mph, gauges, navigation, everything on the dash and touch screen the it will come back on like nothing happened. I have contacted 2 dealers and they say I need to download updates but when I go to update it is not required or needed. | Crash: No Fire: No | Unknown |
| Feb 2024 | ENGINE | I purchased this vehicle used with approx 16k miles on it. Not long after getting it - as I was driving it started dinging and then would shut off. Sometimes I’m in the fast lane going 75Mph and it’ll just shut off. The dealership can’t get it to repeat itself. They said they’ve heard of it happening before but it throws different codes. There’s no rhyme or reason to causing it to shut off, but here lately I don’t even get the warning bell. It just dies on me. As soon as i shift it to neutral and press start it’ll restart instantly. But it’s scary nonetheless, and causes me to drop speed instantly and poses a safety risk especially when I have semi’s or other vehicles close behind. | Crash: No Fire: No | Unknown |
| Jan 2024 | UNKNOWN OR OTHER | The Flex Tailgate has on multiple occasions has malfunctioned in cold temperatures. I have had instances where I can get it open when I have vital supplies in the bed of my truck because of the Tonneau Cover being on (I have a hard cover made for this truck) and the tailgate malfunctioning. I have also had an instance where my tailgate opened (after clicking shut) while driving without the notification coming up on my dash. I could've been held liable if my equipment fell out and caused an accident. Moral of the story this truck as a lot of issues when temps are below freezing even after being warmed up for 15 minutes or longer. I wouldn't recommend this truck based on the function of the Flex Tailgate. I would prefer a classic a handle and less tech now that I have seen it fail so many times. | Crash: No Fire: No | Unknown |
| Jan 2024 | SERVICE BRAKES | The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the brakes seized, and the service brakes warning light illuminated. Additionally, the contact stated that the vehicle jerked forward. The vehicle was driven to the residence and parked. The contact stated that the vehicle was turned off; however, the service brakes warning light remained illuminated. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was not made aware of the failure. The failure mileage was approximately 34,500. | Crash: No Fire: No | 34,500 |