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 2023 | ELECTRICAL SYSTEM | My 2021 GMC 1/2 Serria SLT 4x4 Crew Cab short bed, V-8 Gas engine with Automatic Transmission. I bought this pickup used with apprx. 41k miles on it. I had it about 2 months when I went out to start it and the battery was completely discharged, it would not even click or any lights come on. I hooked it up to a battery charger and got it started, took it to a shop and had the battery and alternator check which both were ok. Drove back home and went out the next morning and the battery was completely drained again, got it started and went an put in a new battery. 16 days later it did the same thing this time it smelled like wires burning when I opened the hood. Called the dealer I bought it from and they put it on a diagnostic machine for over 3 hours could not find anything. Then next morning the battery was again completely drained. Got it started and took it to another shop to get it checked out and after almost 3 hours there they found nothing. Came back home an it sat for just over 40 hours and again the battery was completely drained. I could smell what I think is plastic or rubber when I opened the hood again. My main concern is that this may be a fire hazard and could not only burn up my pick up but my house as well. The check engine light has came on but goes off so I am at a complete loss on this and seems as if GM is not concerned either. I have tried contacting GM but so far nothing other than a note from GM Canada that I need to contact the GM USA, and again that is the only thing I have gotten from anyone. Perhaps this is just a odd thing, I don't know but I do know it is not a safe thing. | Crash: No Fire: No | Unknown |
| Nov 2023 | WHEELS,UNKNOWN OR OTHER | 5 days after purchasing and While driving down the interstate at 80 mph, there was a loud clunk at the same time the back wheels locked up for a split second, long enough to burn the tires and throw everyone in the vehicle forward then the vehicle continued on. It happened three more times, we trailered it and brought it to the dealer. They said nothing is wrong with it. However, I was able to locate the previous owners who stated they'd been bringing it to several dealerships to have it taken care of for the past six months and every dealer said that nothing is wrong with it. But the same thing happened to them for six months. One mechanic in Idaho even replaced the motor trying to fix it and it still continued. The dealer I purchased from never mentioned it having a new motor, and I pulled the Carfax report and it shows several times it was in the shop including the motor replacement, but the shop visits aren't detailed it just says maintenance. Several mechanics we've spoken with say it's in the transmission, drivetrain. But the dealer refuses to do anything unless it'll replicate when they test drive it. But they don't test drive it on the highway or for a long enough time. Multiple owners now in multiple states the same problem and no one will help. This could be a catastrophic incident if the roads had been a little wet or someone was close enough behind us when it happened it would have been a serious car accident, if not worse. I am not sure you can help but Im reaching out to everything that I can find. | Crash: No Fire: No | Unknown |
| Oct 2023 | STEERING,SERVICE BRAKES,ENGINE | "Service parking brake" "steering assist is reduced drive with care" comments showed up on screen…check engine light on, truck shaking/ vibrating completely as if wanting to turn off this all happened while driving on the road and randomly happened…please help..very Concerned | Crash: No Fire: No | Unknown |
| Sep 2023 | ENGINE | Lifters camshaft malfunction. Known issue with 2021 GMC Sierra 20,000 miles | Crash: No Fire: No | Unknown |
| Sep 2023 | ELECTRICAL SYSTEM | Tailgate opens when driving and when parked. I thought something must of hit the button on the dash the first time it happened but now it is constantly doing it on its own. It has damaged the hitch. | Crash: No Fire: No | Unknown |
| Aug 2023 | SERVICE BRAKES | WHEN DRIVING HOME AFTER PICKING UP MY 2.5-YEAR-OLD AND 6-MONTH-OLD THE BREAKS FELT VERY ODD AND NOT RIGHT. WHEN I APPLIED THEM, IT FELT ROUGH TO APPLY AND THEN HEARD A NASTY SOUND COMING FROM THE REAR OFF TRUCK. I TOOK MY TRUCK IMMEDIATELY TOO THE DEALER AND JUST GOT THE PHONE CALL BACK THAT THE MASTER CYCLINDER FOR MY BRAKE SYSTEM NEEDS TO BE REPLACED. THIS VEHICLE HAS 22,500 MILES ON IT AND IT ALREADY NEEDS SOMETHING FIXED LIKE THIS IS PRETTY SCARY SINCE MY FRIEND JUST HAD IT HAPPEN TO THEM AND THEY GOT IN A MAJOR CAR ACCIDENT. THANK GOD I DIDNT HAVE TO PUT MY FAMILY THROUGH THAT. HAVING A BREAK FAILURE IS SOMETHING NOONE WANTS AND NOT WHEN THE VEHICLE IS PRETTY MUCH BRAND NEW STILL. THE DEALER HAS CONFIRMED THAT THIS IS A VERY RARE CODE IN TERMS THEY USED TO BE HAPPENING. THERE WAS NO WARNING LIGHT OR ANYTHING IT JUST HAPPENED THEN AS I WAS TAKING IT UP TO THE DEALER, I GOT THE SERVICE BRAKE SYSTEM ALERT ON MY DASH. | Crash: No Fire: No | Unknown |
| Aug 2023 | POWER TRAIN,ENGINE,FUEL/PROPULSION SYSTEM | After having simple oil and filter, and engine and cabin filter replaced at Alpine Buick GMC in Colorado Springs, CO, I received my vehicle back and noticed a complete difference in performance. It hesitates when accelerating, stays low in every gear, and bounces, and I mean bounces hard, when shifting gears, especially slowing down. When slowing down, as it shifts to the next lower gear, it almost pushes the truck forward against me pushing the breaks. Then, when feathering to accelerate slowly, it almost bounces back up to speed, hesitating until I let off the accelerator pedal a little, and it immediately shifts to about 1000 rpm in gear. I have to push really hard for it to go up a gear, and when it does, it has lost all power. My vehicle doesn’t run right anymore after my service appt. I have brought it to my hometown dealership and they say it runs fine and nothings wrong. But there is something wrong with it. | Crash: No Fire: No | Unknown |
| Aug 2023 | POWER TRAIN | Transmission shifting is at times confused causing the vehicle to jump forward shifting to first gear. It pushes your vehicle 2-5 miles an hr faster when slowing down. The transmission also does the opposite when letting off the accelerator, shifting fast to a lower gear slowing the vehicle down quickly in a jerking motion at times. I have an 8 speed transmission. GMC dealer is replacing my torque converter, stating this may fix the issue, but it is a safety concern. | Crash: No Fire: No | Unknown |
| Jun 2023 | ELECTRICAL SYSTEM | My son got into the car to drive it and saw a black screen with a message that states “update failed, see dealer” and had multiple languages. Since that date, he has no GPS or backup cam, which he relies on as a new driver. Nothing at all in the info system works. | Crash: No Fire: No | Unknown |
| Jun 2023 | UNKNOWN OR OTHER | I have HD surround vision cameras. I was parallel parking very slowly. The back end of my truck was in so I was watching the camera to see the front right of my truck and the back left of the other vehicle. I could see both vehicles including the road between them. There was space between the vehicles on the camera when I hit the other car. I called Sewell Buick Gmc and explained the camera might need calibrating. They sent a loaner car and picked mine up, When the driver arrived I explained the situation. It surprised his so I said get in my truck and put in reverse to activated the camera and watch me as I walk toward the right front tire. He saw mw as I approached, however, when I got right next to the tire I disappeared from she screen. GM said the vehicle was operating as designed. Operating as designed? They designed a SURROUND camera to show objects until they get next to the vehicle. Imagine if it was a toddler. | Crash: Yes Fire: No | Unknown |
| May 2023 | STEERING | Steering wheel stopped working | Crash: No Fire: No | Unknown |
| May 2023 | UNKNOWN OR OTHER | I have a GMC Sierra 2021 Denali. The vehicle currently has less than 16,000 mile and is at the dealership service department for lifter replacement. This is an extensive repair considering how new the vehicle with low miles. From extensive online research and collaborating with others, this is a common concern with multiple GMC vehicle that's been on GMC radar starting in 2017. GMC haven't yet issued a recall for these products and the consumers are footing the bills. Please put pressure on GMC to rectify their wrong. | Crash: No Fire: No | Unknown |
| May 2023 | ELECTRICAL SYSTEM | While towing a new 2023 Airstream trailer on Interstate route 95 in New Hampshire my GMC Sierra truck driver display flashes a " check Trailer wiring" error message. When this message appears all brake function to trailer is lost makeing driving unsafe. The connection sometimes can intermittently and continuously reconnect momentarily and brakes reengage for seconds until they disengage again with repeated "check Trailer wiring" error message . Sometimes the brakes just disengage end never reconnect until error codes is cleared by GMC dealership. It's extremely unsafe to pull off exit and have trailer brakes reengage because they jam with high gain because vehicle brakes need to be applied very hard to over compensate for "NO" trailer brakes. GMC dealership has identified certain error codes with their computer but NO suggested fix! | Crash: No Fire: No | Unknown |
| Apr 2023 | ENGINE | The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle was shaking with the check engine warning light illuminated. The independent mechanic was made aware of the failure; however, the vehicle was not diagnosed or repaired. The contact stated that the independent mechanic had previously replaced the lifters, but the failure recurred. The manufacturer was not made aware of the failure. The failure mileage was approximately 20,095. | Crash: No Fire: No | 20,095 |
| Apr 2023 | STEERING | My 2021 gmc Sierra displays (service power steering with care) the truck only has 13184 miles and barely moves. | Crash: No Fire: No | Unknown |
| Apr 2023 | TIRES | The contact owns a 2021 GMC Sierra 1500. The contact stated that the tire pressure warning light illuminated and that the TPMS sensor was not indicating the pressure for each tire. The vehicle was taken to the dealer and the dealer stated that no failure was found; however, the TPMS was reset, but the failure reoccurred. The vehicle was taken back to the dealer and the TPMS was reprogramed, but the failure persisted. The manufacturer was not contacted. The failure mileage was 5,000. | Crash: No Fire: No | 5,000 |
| Apr 2023 | STEERING,SERVICE BRAKES,ENGINE | While driving home from work around 6 am, my car had multiple warning lights and warning messages come up all of a sudden. Immediately after that I lost my power brakes and steering and was not able to control my car at 40 mph. I was lucky the light I passed was green and there was no other traffic. I was able to bring my truck to a stop after more than a quarter mile by putting all my weight on the brake pedal. The truck was towed to the dealer and has been there ever since. | Crash: No Fire: No | Unknown |
| Apr 2023 | STEERING | I parked my car for about an hour after driving for months with absolutely no issues or warnings. When I started my car and went to pull off the steering wheel locked up and I couldn’t turn it. A message appeared on the screen saying: Service power steering drive with care, and an esc message. A light also appeared. I turned the car off and let it sit for an hour. When I started it again everything worked fine. My dealership won't do anything because the warning codes went away, and the vehicle is not included in any current recalls. When looking up this problem it appears there are multiple recalls for the exact same issue on other 2021 Yukon and Tahoe models but not the Sierra. Though I see many forums and threads complaining about the same problem on the Sierra's. Since it is the same vehicle and systems as the Yukon, shouldn't the same recall apply? | Crash: No Fire: No | Unknown |
| Apr 2023 | ENGINE | DRIVING DOWN THE HIGHWAY THE ENGINE STARTED SKIPPING AND STARTED BLOWING OUT BLACK SMOKE, AND QUIT RUNNING IN THE MIDDLE OF THE HIGHWAY. FOUND OUT THE HAD A FACTORY LIFTER DEFECT ON MY MODEL AND A SERVICE UPDATE WAS SUPPOSED TO BE DONE ON THE TRUCK CHANGING OUT THE LIFTERS HOWEVER EVEN THOUGH I HAVE GONE TO DEALERSHIP FOR ALL THE MAINTENANCE THE SERVICE HAD NEVER BEEN DONE OR TOLD TO ME. THIS COULD HAVE BEEN VERY DANGEROUS JUST ENGINE FAILURE THE SERVICE BY GMC N212353840 | Crash: No Fire: No | Unknown |
| Apr 2023 | ENGINE | I was operating my vehicle in northern Minnesota with a temperature well below freezing. Vehicle warning light came on that said "turn off vehicle" which I did. When I went to start it again it would not turn over. It appeared that a large amount of oil had expelled from the vehicle. It was very dangerous as I was in a very remote area with very poor cell service and extremely cold temperatures. I couldn't even run the vehicle to stay warm. The vehicle was towed to the nearest GMC dealership where they examined the vehicle and stated that the seal of the oil filter had blown off. They further stated that the oil filter which was installed by Valvoline was the wrong size. Valvoline tested the Champion oil filter and came back with findings that the filter was the correct size and noted no damage to the filter. Either there is an unknown problem with the GM engine or the Champion oil filter. Each corporation continues to point fingers at each others product. | Crash: No Fire: No | Unknown |
| Mar 2023 | SERVICE BRAKES | I bought a loaner 2021 GM Sierra 1500 in Aug. 2021 from Starling Buick GMC, Venice, FL with 1600 miles on it. I used the Sierra to move items from my houses in my trailer from both FL to PA and PA to FL. On each trip The trailer brake controller would go out while driving. The first time it occurred was on a trip from FL to PA, during this trip it happened at least four times. Upon arrival in PA I took it to Kelly Buick GMC in Allentown, PA. They looked over the vehicle, saw there were codes in history indicating an issue with the trailer brake system but could not replicate it or pinpoint what part of the system was faulty. The dealer told me that GM will not fix it if it is in history only if it is currently giving a code. On the return trip back to FL from PA, same thing several times it occurred, took it back to the selling dealer Starling, and they gave me the same speech as Kelly , can't fix it without a current code. Next trip from FL to PA, same thing took it to Kelly again, same response. Back to FL from PA, same thing, Starling gave me the same response, they can't and won't do anything. I told Starling service rep I guess I need to die before you do anything, she was completely indifferent to my comment and backed GM without any regard for my safety. It is sporadic and inconsistent and obviously only occurs when there is a trailer attached. They said it was my trailer so I took it to a trailer mechanic, we tested it on its own and on another vehicle with no problem. The brake controller failed while hauling a trailer potentially allowing a serious if not deadly accident with improper braking capabilities. Even though two dealers in two different states acknowledge there is an issue they refuse to correct it because they can not replicate it. The brake controller lights would go out as you're driving indicating the brake controller is not connected to the trailer and providing a supplemental braking system. 2022 and 2023 have this issue. | Crash: No Fire: No | Unknown |
| Feb 2023 | ELECTRICAL SYSTEM,ENGINE,FUEL/PROPULSION SYSTEM | Less than 5 minutes after my husband and 2 children parked the car and came inside, a neighbor walking rang our doorbell to let us know there was something on fire in our driveway. We ran to the back to find his truck engulfed in flames coming from the engine. We quickly called 911 and exited the house/property. The truck continued to burn with 20-25 foot flames and very black smoke for about 40 minutes until the fire department was able to control the fire. The fire was hot enough that the entire engine was significantly burnt, the seats and steering wheel were gone, the glass shattered and melted, and the tires exploded and melted. Thankfully, everyone was out of harms way and safe through this incident. However, it has been extremely traumatic on my family and neighbors and has taken a lot of time and energy to try to deal with this. The car sat in our driveway for over 2 weeks with a very potent smell causing headaches until GM and our insurance finally investigated. There is damage to our siding, driveway, landscaping, basketball hoop, trampoline, and neighbors fence. The car was only 2 years old and scares me how quickly it went up in flames and how much worse this could have been either 3 minutes earlier or if it was parked in our garage. | Crash: No Fire: Yes | Unknown |
| Jan 2023 | AIR BAGS,SEAT BELTS | I get a "Service Safety Restraint System" warning sporadically when driving. No known cause and the vehicle has never been in an accident. This started happening after my last service at Capital Buick GMC in Smyrna, GA on January 6th, 2023. | Crash: No Fire: No | Unknown |
| Jan 2023 | ENGINE | 2021 GMC Sierra 1500 AT4 6.2L engine, Little over 39000 miles, Purchesed May 2021. This is the second time the vehicle has had this issue. The first time was aprox 15000 miles. I reported the issue to NHTSA-ODI on 6 Dec 2021 tracking # 11442943. I was driving down the interstate I heard a rattling coming from the engine (same as I had heard with the first issue). The check engine came on I ask On Star to do a digonsotic report (see attached report). The report indicated a Fuel Management System issue detected advised to reduce vehicle speed and pay load as possible. I was told by GM certified mechanics that this issue could cause the engine to lock up and come to a complete stop on the roadway. I fill that these vehicle are unsafe to operate under these conditions and may cause serious accidents. GM has known about these issues with these vehicles for several years and has failed to correct the problem. | Crash: No Fire: No | Unknown |
| Jan 2023 | ELECTRICAL SYSTEM | The contact owns a 2021 GMC Sierra 1500. The contact stated while driving at various speeds with the ONSTAR/GPS, turn-by-turn driving directions activated, there was an unknown notification flashing on the instrument panel and radio. The speedometer was obstructed and failed to work as needed. The screen sporadically went blank. While depressing the dismiss button on the steering wheel, the button failed to correct the failure. There were no warning lights illuminated. The vehicle was taken to the local dealer and the system was rebooted; however, the failure recurred. The vehicle was taken back to the local dealer and the contact was informed to turn off the vehicle, open the door, and then restart the vehicle to reboot the vehicle. The vehicle was taken to another local dealer, Bill Cramer Chevrolet Buick GMC (2251 W 23rd St, Panama City, FL 32405) but the vehicle was not diagnosed or repaired. The manufacturer was contacted but no additional assistance was provided. The failure mileage was approximately 10,450. | Crash: No Fire: No | 10,450 |