Complaint volume
437 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
2020 GMC Sierra Complaints
437 consumer-submitted complaints on record for the 2020 GMC Sierra, grouped by component category.
437 Total complaints
11 Crash reports
5 Fire reports
6 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, electrical system. Use those categories as a test-drive checklist instead of judging the vehicle from the total count alone.
Severity flags
Enriched records include 11 crash reports, 5 fire reports, 6 injury reports, and 0 fatality reports. These fields come from complaint records and should be read in context.
Mileage clue
Mileage is available on 121 complaints, with an average reported failure mileage of 45,188 miles. Compare that with the mileage on the listing.
Questions to ask the seller
- Have you had any problems related to engine, power train, electrical system?
- 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 2020 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.
2020 GMC Sierra
Build buyer checklist Compare with other years Sends year, make, and model to pre-fill your checklist.
How severe are the 2020 GMC Sierra complaints?
11 Crash
5 Fire
6 Injury
0 Fatality
29 Towed
4 Medical attention
What are the most common 2020 GMC Sierra complaint categories?
ENGINE 130
POWER TRAIN 38
ELECTRICAL SYSTEM 22
POWER TRAIN,ENGINE 17
SERVICE BRAKES 16
STEERING 14
UNKNOWN OR OTHER 14
ENGINE AND ENGINE COOLING 10
SUSPENSION 9
ELECTRICAL SYSTEM,ENGINE 8
437 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| Aug 2022 | UNKNOWN OR OTHER,ENGINE | Vehicle engine went out on truck. | Crash: No Fire: No | Unknown |
| Jul 2022 | STEERING | I started my truck like normal and my service power steering light drive with care message came on and then Service ESC and the traction control light. My power steering was completely gone. I researched and found that 2020-21 GMC SUVs were recalled due to the same issue. My GMC truck is doing the same thing. I barely made it home from the store not having power steering is extremely dangerous, I still have no power steering. I just purchased this truck from CarMax last month. | Crash: No Fire: No | Unknown |
| Jul 2022 | STEERING,VEHICLE SPEED CONTROL,SERVICE BRAKES | The truck stated to have the check engine light on, by the time that happened the brakes were hard to step on it and the steering wheel hard to turn, I had been asking to GMC superior of Siloam springs to check the truck because, got scared while I couldn't make stop the truck while on traffic, but they don't had open appointments for that day or the other following days, so a week after they got one and I missed because my work, I set another one at GMC on Springdale but they want me to charge me whenever the truck has an extended warranty, so I told them to leave it like that so finally got another appointment at Siloam springs location but while driving down there the same thing happened all the light on warning messages on the dash board start showing up and the brakes were hard to step on it and the steering wheel hard to turn, I got told them what was happening, about and how exactly happened. That day after 30 minutes I got a call saying that it was fixed I still asked if they were sure he said yes, the next day I almost crashed with a neighbor at my work place because I couldn't stop the truck, so today I took back the truck and the guy at the desk told me that they may just erase the codes and don't really checked what was wrong, I'm just filling this report because even if I got full coverage on that truck, I'm not gonna be responsible if I'm involved in an accident. | Crash: No Fire: No | Unknown |
| Jun 2022 | VEHICLE SPEED CONTROL | I investigated and Unintended Acceleration crash that occurred on 8-9-2021. The vehicle had just left a body shop where it had repairs to the left front of the vehicle near the ECM. The driver reported the vehicle would not slow down. He face timed a witness and showed her his foot was on the brake and not the accelerator pedal collaborating his statement. The 2020 GMC accelerated to 93 miles per hour crashing into the back of a Cadillac Escalade. Upon impact the fuel tank of the Cadillac exploded igniting both vehicles on fire and burning a fed-x truck that was folded in half from the sever impact. The EDR report stated the brakes were applied fully for a full 5 seconds prior to the crash while the vehicle was still accelerating. The accelerator was reading a constant 57% during the lead up to the crash and the brake rotors showed heat related glazing from excessive braking. The engine torque was also at 1023NM leading up to impact collaborating Unintended Acceleration further. Based on the evidence gathered my opinion is there was a short in the components in the left front of the vehicle most likely the ECM harness that caused the crash. It is unknown if the damage was caused by the previous crash, the body repairs or a manufacture defect at this time. The radiator had also just been replaced so moisture could have contributed to the malfunction. If moisture shorts APP-1 to APP-2 the safety systems can fail to detect a single fault because it causes redundant faults | Crash: Yes Fire: Yes Injuries: 7 Towed Medical attention | Unknown |
| May 2022 | SERVICE BRAKES | This vehicle was involved in a fatal crash when it rear ended an SUV stopped at a red traffic light. The driver alleges mechanical failure of the brakes. Police performed a vehicle download which captured 5 seconds of pre-accident data. The download shows the accelerator pedal was fixed at exactly 57% the entire 5 seconds pre-crash while the driver simultaneously applies the brakes the entire 5 seconds. A city bus captured the crash on a dash camera. Despite the driver desperately applying the brakes, the vehicle's speed continued to increase and the driver was unable to avoid the collision, and burst into flames upon impact. The vehicle mileage is less than 2,500. | Crash: Yes Fire: Yes Injuries: 2 Towed Medical attention | Unknown |
| Apr 2022 | ENGINE | A VERY STRONG "AMMONIA" ODOR COMES INTO THE CABIN. THIS HAPPENS WHEN THE DEF FLUID IS GOING INTO THE EXHAUST SYSTEM FOR THE REGEN PROCESS. THE ODOR MAKES PEOPLE INSIDE NAUSEOUS AND DIZZY. MUST OPEN WIDOWS OR STOP AND GET OUT OF THE VEHICLE. OUR GMC DEALER CAN FIND NO CODES OR PROBLEMS WITH THE EXHAUST SYSTEM. WE HAVE ALSO NOTICED THAT THE DEF FLUID HAS GONE DOWN VERY QUICKLY SOMETIMES DURING THIS EVENT. IT IS RANDOM. SOME DAYS NOTHING, OTHER TRIPS 3 AND FOUR TIMES THAT THE ODOR OCCURS. LOOKING ONLINE- THERE HAVE BEEN MANY POST ABOUT THIS PROBLEM. | Crash: No Fire: No | Unknown |
| Mar 2022 | POWER TRAIN | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle shuddered. The vehicle was taken to the dealer however, the mechanic could not duplicate the failure. The vehicle was then taken to Gilland Chevrolet GMC (3071 N US Hwy 231, Ozark, AL 36360) where the contact was informed that the vehicle already had new transmission fluid filled in the transmission. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 42,000. | Crash: No Fire: No | 42,000 |
| Mar 2022 | STEERING,ELECTRICAL SYSTEM,VISIBILITY | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving in the snow, the tire pressure and power steering warning lights illuminated. The vehicle was not diagnosed or repaired. The vehicle was taken to a dealer where it was confirmed that there were no recall or warranties that would cover the repairs for the warning lights. The failure mileage was 140,000. | Crash: No Fire: No | 140,000 |
| Feb 2022 | STEERING | Steering locked up after normal use at lunch. After sitting, traction control light then on and wheel would not turn after work. Did a computer reboot and steering released. Results still pending, she is not home yet. | Crash: No Fire: No | Unknown |
| Feb 2022 | AIR BAGS | I receive at random times the warning in the DIC (driver information center) on the dash of my car together with an air bag warning light. I have had this happen sometimes frequently and sometimes not for a thousand miles. I have taken it in at least 8 times, some parts were replaced in seat belt, but it continues to show up. The problem is it now doesn't leave a code but my local dealer said if it ever came up when I could get it to them to bring it in and leave it running. that happened and I brought it in the ran a computer check and got a code. I had to leave for Florida 2 days later, so they said bring it in to a dealer in Florida, give them the code, which I did, they checked it but said they will not replace parts without an active computer code. Problem started around 11K miles; I have 32K miles, and dealer wont replace parts unless they know they are bad. | Crash: No Fire: No | Unknown |
| Jan 2022 | ELECTRICAL SYSTEM,ENGINE | I have a lifters problem that the dealership takes more that three weeks to fixed without a loaner car, then i have electrical problems where the truck doesn't start at all without any warning and that's it's dangerous, never now where its going happen | Crash: No Fire: No | Unknown |
| Jan 2022 | SUSPENSION | A vehicle with 45,000 Miles had ball joint shear from the upper control arm of front left suspension resulting in wheel separation from the ball joint. Similar situations happening with similar 2020 GMC Sierra's (Note: NHTSA Recall Notice, No. 21V718). Could have resulted in a vehicular crash if speed had been increased prior to separation. | Crash: No Fire: No | Unknown |
| Dec 2021 | ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated that shortly after refueling while driving under 15 MPH, the check engine and service emissions warning light illuminated. The contact stated that an unknown reset was performed related to TSB: 10173675 (Engine). The vehicle was not yet fully repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 46,000. | Crash: No Fire: No | 46,000 |
| Nov 2021 | SUSPENSION | At 8,000 miles I started hearing a clunking noise in my truck when I hit a small bump or back up out of drive way. Brought in and GMC stated it was normal and no issues at walser buick gmc of Roseville. Brought I back again because it was getting worse and could hear it every time I slowed down and accelerated. Then stated they need to order spacer bushings at walser of Bloomington. Then went back for 3rd time and installed them at Bloomington.After 600miles noise was back and is getting worse again. I called Walser of Bloomington again and said I need to drive it for 1000 miles to break in spacers. So now we have 11,000 miles on truck with same noise again and its going back again because needs to get fixed. GMC is just asking for something to happen. Also when this first happened at 8,482miles I was on 35w and the rear end started wobbling and gave me a small death wobble but I slowed down to control it. That’s when I brought it in and it could of hurt or killed somone. | Crash: No Fire: No | Unknown |
| Nov 2021 | SERVICE BRAKES | Brakes have been squealing since 4000 mile mark. Dealer states it’s normal. | Crash: No Fire: No | Unknown |
| Oct 2021 | TIRES | The contact owns a 2020 GMC Sierra 1500 equipped with Goodyear Tires, Tire line: Wrangler AT/S, Tire Size: LT275/65/R20, DOT Number: PJOTJB1V. The contact stated while driving 65 MPH, there was a slight wobble and then an impact was felt when the rear passenger’s side tire tread separated and damaged the rear fender and bumper. The contact pulled over and had assistance replacing the rear passenger’s side tire with the spare tire. The dealer was made aware of the failure and was in possession of the failed tire. The manufacturer was not made aware of the failure. The failure mileage was unknown. | Crash: No Fire: No | Unknown |
| Sep 2021 | ELECTRICAL SYSTEM,SERVICE BRAKES,FORWARD COLLISION AVOIDANCE | Own a 2020 GMC Sierra AT4 with 13K miles and I owned the truck for 1 year. All of a sudden my vehicle started receiving multiple warning messages. Electronic Stability Control, Antilock Braking System, ECM, reduced Engine Power, etc. I see there was a recall for 2019 GMC Sierra's for the same issues. Why isn't 2020 GMC Sierra's not also part of that recall ? It is ridiculous that a brand new truck has these types of serious issues affecting so many vehicles. Why is GMC allowed to continue to sell later model trucks after the 2019 recall with the exact same ESC and Anti-lock Braking system problems ? | Crash: No Fire: No | Unknown |
| Sep 2021 | ELECTRICAL SYSTEM,SERVICE BRAKES,ENGINE | Two times while on the freeway the service parking brake and engine lights came on and starting braking. Could not drive over 20 mile an hour. Both times taking to dealer the lights where not on and they could not find anything wrong. I even have video of it happening. | Crash: No Fire: No | Unknown |
| Sep 2021 | SUSPENSION | The leaf springs appear to have failed. The vehicle is available for inspection. If the leaf spring brakes, control of the vehicle could quickly become an issue. On 9/24/21 I brought my truck into the local GMC dealer for inspection. The service technician indicated the leaf springs show “possible overloading” and recommended air bags to level the truck. The heaviest load for this truck has been a 4,000 lb. fiberglass fishing boat. At this time, no one else has inspected the truck. The truck, when empty, sits lower in the rear than in the front. If a small trailer is attached, it becomes even worse. Oncoming cars flash their headlights thinking mine are on high beam, which they are not. | Crash: No Fire: No | Unknown |
| Sep 2021 | SUSPENSION,POWER TRAIN,SERVICE BRAKES | I purchased the 2020 Sierra 1500 because the label on the truck frame states that it can tow 9300lbs. Subsequently, in April 2021, I purchased a 34' Travel Trailer with a max capacity of 8995lbs. In August, I received a notice from GMC that they overstated the towing capacity by 500lbs. The new towing capacity is 8800lbs. GMC's response to my request for a refund was that they were not going to help me. Their solution is that I can be provided a new sticker by the dealer upon request. This does not resolve my issue, nor the issue of other Sierra owners who purchased this vehicle because of its stated towing capacity. In doing research, it appears that in model year 2014, GMC faced a class action lawsuit for misrepresenting their capabilities. I believe that this malpractice is a safety concern for me and many others. Attached is the towing label on the frame and the letter from GM. | Crash: No Fire: No | Unknown |
| Sep 2021 | ELECTRICAL SYSTEM | Bought 9-4-2020. On 9-4-2021 went start vehicle and no electrical power, battery dead. Will not hold charge to start. Brand new purchased at Morgan GMC in Shreveport Louisiana | Crash: No Fire: No | Unknown |
| Sep 2021 | SUSPENSION | I was driving my 2020 GMC Sierra AT4 at about 15mph on a 2 way city street slowing for a traffic light when my vehicle started to shake violently...at first thinking it was a flat, but the shaking was much different. As I was slowing in anticipation of the light, now at about 5mph, my truck suddenly dropped and stopped. This would have been catastrophic at freeway speeds! I immediately thought maybe someone had tried to steal the wheel overnight as I knew now it was not simply a flat, but knew I had wheels locks and thought that unlikely....this was while I was exiting my now parked truck. I knew the problem was on the front passenger side, and was shocked as I rounded the vehicle from the front only to find the entire front wheel assembly folded flat under my truck. The entire brake assembly was still intact, but the front drive shaft was pulled out, as well as the upper and lower ball joints. The brake hose became severed in this incident. | Crash: No Fire: No | Unknown |
| Aug 2021 | ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL,FORWARD COLLISION AVOIDANCE | Issue 1: Front left sensor(s), after a rain, car wash and now after an oil change, continuously vibrates the drivers seat and the red light warning stays lite indicating that an obstacle is located near the left front of the truck. This has happened on several occasions and after a time both indicator stop. Issue 2: When traveling on a freeway, twice now, the cruise control suddenly disengaged or decreased mileage, as if it had detected a vehicle in front of us. There was no vehicle within a quarter mile of us front or back, nor any vehicles on the side. No debris in the road either. Usually when the adaptive cruise is set and detects something in front the icons on the dash turn orange and starts to flash. That didn't happen, rather the cruise icon changed to blue in color and the truck slowed. This I would consider a safety risk. Both instances (December 2020 and April 2021) have been reported to a dealership and noted in a file. When the customer care person attempted to get malfunction codes, nothing appeared to be wrong with the vehicle. | Crash: No Fire: No | Unknown |
| Aug 2021 | ENGINE | Repeated issues with exhaust and emissions components. | Crash: No Fire: No | Unknown |
| Aug 2021 | ENGINE | Found improperly installed rear seals. The truck leaked oil and had to be towed to gmc dealership in Monahans Texas to be repaired. 1 month later the truck leaked oil again. | Crash: No Fire: No | Unknown |