Complaint volume
436 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
436 consumer-submitted complaints on record for the 2020 GMC Sierra, grouped by component category.
436 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
436 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| Feb 2025 | STRUCTURE | Tailgate opened on highway with cargo in bed. Also tailgate opens randomly when parked. This has happened many times, creating very dangerous and unexpected situations Numerous contacts to the manufacturer have been unsuccessful in getting the hazard placed on recall. Numerous incidents. Keeps happening | Crash: No Fire: No | Unknown |
| Feb 2025 | ENGINE | My engine has had continual random piston misfire issues, I have changed the spark plugs, fuel injectors, and cat converter. The vehicle has "dynamic fuel management" (DFM) where four of the cylinders turn off when the load on the engine is low and turn back on when the load is high. A mechanic reviewed the vehicle and determined that all eight cylinders are turning off while driving due to the DFM. When it misfires there is momentary loss of power that potentially puts others at risk. A dealership performed a repair per a Bulletin but the issue was not fixed. The mechanic indicated this is a software issue with the computer update per the Bulletin. I have installed a DFM disabler to prevent DFM from working, don't have misfires, but this is an engineering issue that GM hasn't/won't address. | Crash: No Fire: No | Unknown |
| Feb 2025 | STEERING | I went to start my truck after going into the store and the Service Power Steering ESC warning came on and I had no power steering. This is a very dangerous situation without power steering in the vehicle and someone is bound to get seriously injured if this happens while they are driving. I have read numerous threads on this same issue and it does not look like GM has taken this into accounty by recalling all these vehicles with this same exact issue. While most complain that when they take it to the dealership, they cant find any error codes, or when the replace the modules it starts creating more issues with other electronics. GM needs to take care of this issue with the power steering module so the safety of their drivers is not compromised. | Crash: No Fire: No | Unknown |
| Feb 2025 | STEERING | The ESC comes on and loss of power steering | Crash: No Fire: No | Unknown |
| Feb 2025 | ENGINE | The engine failed. There was no warning. The truck literally just cut off in the middle of the road. I never saw any lights or there was no symptoms to lead up to this incident. | Crash: No Fire: No | Unknown |
| Feb 2025 | TRACTION CONTROL SYSTEM,ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving 65 MPH, the check engine and the traction control warning lights illuminated. The contact stated that a dealer was contacted. The vehicle was taken to a dealer where it was diagnosed and determined that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure and informed the contact that he would receive a callback. The approximate failure mileage was 87,000. | Crash: No Fire: No | 87,000 |
| Feb 2025 | ENGINE | At 125,000 miles, the CEL came on and the code is P0016, which is for the timing chain has stretched and jumped a tooth. The engine was new in 2019 and in 2021, they redesigned the timing chains due to early failure. The oil pump belt is listed for inspection/replacement at 150,000 miles, but the timing chain does not give any interval for replacement and should easily outlast the oil pump belt to at least 250,000 miles. GM knows that there is a timing chain issue with the 3.0 Duramax LM2 engine and it is costing owners between, $7,800 and $10,000 to repair. | Crash: No Fire: No | Unknown |
| Feb 2025 | POWER TRAIN | GM 10L80 Speed Transmission Pump Idler Gear Failure causing erratic shifting, lurching, or being stuck in gear. Dealer confirmed and recommended to replace the transmission. Transmission was replaced out of pocket in December. The issue is widespread on youtube. | Crash: No Fire: No | Unknown |
| Feb 2025 | ENGINE | Wife and I bought a truck from Serra Chevrolet on May 28 2024. We drove 180 miles and the engine blew up. Had it towed to another dealership in Louisville Kentucky at that point they replaced the engine. When we picked up the truck we had to pay $16,275.08. We contacted Gm and was told that the selling dealership should have taken it off of being certified pre owned but they didn’t. Was told they know to do it to future vehicles and there is no reimbursement . Gm website still has it listed of have a warranty till December 2025. We had 3 weeks of a truck rental at roughly $1,200.00 per week. Had another rental for another. 3 weeks I have paper work from a local dealer stating it still has warranty which would have covered complete expense of engine work We live in Ohio and had to travel back and forth 6 times. Hope there is some help for us. | Crash: No Fire: No | Unknown |
| Feb 2025 | ENGINE,LANE DEPARTURE,FORWARD COLLISION AVOIDANCE | I have had no issues with my vehicle since I purchased it in July 2022 and keep up with the routine maintenance on it. About 2.5 weeks ago I was driving to work like I normally do and the truck started making a knocking noise and all these sensors lights came on the dash. The alerts were saying to service the parking brake, service ESC, and that steering assist is reduced and to drive with care. The vehicle also started shaking and would not accelerate properly or shift gears. We ended up taking it to the closest GMC dealership and they were in able to diagnose it just by simply hooking it up, they had to fully dismantle the engine in order to diagnose it. They came back and said cylinder number 4 is damaged as well as the lifters and cam shaft. I am no car expert but it is weird that a car that is relatively new and has the maintenance kept up on it should not experience a serious malfunction like this. What is even weirder is my sister in law has a 2020 Chevy Silverado where the almost identical thing just happened to theirs and it too is now in the show as well needing its engine and stuff repaired. | Crash: No Fire: No | Unknown |
| Feb 2025 | ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving 80 MPH, the vehicle lost motive power and stalled. The vehicle regained power within seconds and the contact was able to continue driving. There were no warning lights illuminated. The contact stated that the failure reoccurred. The vehicle had not been taken to the dealer to be diagnosed or repaired. The manufacturer was made aware of the failure and confirmed that there was no recall on the VIN for the failure. The failure mileage was approximately 50,000. | Crash: No Fire: No | 50,000 |
| Feb 2025 | UNKNOWN OR OTHER | Water entering from the rear window causing rear seats and roof hard cover to get wet and cause a wet odor (humid). 2020 GMC 1500 AT4 | Crash: No Fire: No | Unknown |
| Jan 2025 | ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated while driving and decelerating from 65 MPH to 15-20 MPH to make a turn, the engine made an abnormal knocking sound. The contact was able to drive to the residence. The dealer was notified of the failure. The vehicle was towed to Pechous Repair to be diagnosed. The contact was informed that the engine was blown and needed to be replaced. The vehicle was repaired. The contact later became aware of NHTSA Action Number: PE25001 (Engine, Engine and Engine Cooling); which the contact related to the failure. The manufacturer was not notified of the failure. The failure mileage was approximately 64,298. | Crash: No Fire: No Towed | 64,298 |
| Jan 2025 | UNKNOWN OR OTHER | Shift to park error message to turn vehicle off when already in park. | Crash: No Fire: No | Unknown |
| Jan 2025 | FUEL/PROPULSION SYSTEM | 2020 GMC Sierra Denali – VIN [XXX] On [XXX] while driving the 2020 GMC Sierra to work I noticed a strong gasoline smell inside the cabin. I immediately returned home and parked the truck in the street. Inspecting the driveway where the truck was parked over night, I notice large gasoline spot. The following day I had the truck towed to Boyds Tire & Service center to have the truck inspected. On January 20 Boyds called me and shared the truck had experienced a failure of the High-Pressure Fuel Pump which has been recognized by GM as a recall under N192283991. I called a local GMC dealership about this failure and they stated it would cost $300 to review and would not perform any work under a recall. Also, the dealership stated they could not service the truck for another two weeks, which I cannot be without the truck that long. So, I had Boyds perform the repair the same day. Unfortunately, GM has not listed my truck on this recall. This is the reason for my submittal and request for a full refund of the repair service due to the failed part. This being a very High Risk of Fire and injury and death, I decide to have the repair completed immediately. I have since contacted GM about this incident they will not consider my request for recognizing and reimbursement for service repair. GMC, Case number [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |
| Jan 2025 | STEERING | On 01/07/2025 I got in my truck to take it to GMC for an oil change and 75,000 mile service. When I began to drive I noticed I could barely turn the truck at all. The power steering was not working. Then a warning popped up to have the power steering serviced. The GMC dealership is an hour from my house. The entire drive the power steering didn't work. I explained what was going on to the GMC dealership and when they went to look at the truck the power steering was working again. When I left the dealership the power steering was working. I stopped at a friends house for about an hour and when I went to leave the power steering was not working again. I ended up having to drive an hour again with no power steering and made an appointment with GMC to get the power steering looked at. Currently they haven't commented on the Power Steering function but rather that there is a gear needing to be replaced in the steering column. Upon looking online it shows "Several model years of GMC Sierra trucks have been subject to a recall for intermittent power steering issues related to electrical glitches within the EPS system." However, my truck seems to not be on this list of affected vehicles but there is no other explanation of why this is happening with my truck and GMC has not commented on why it is happening but it is extremely dangerous. | Crash: No Fire: No | Unknown |
| Jan 2025 | POWER TRAIN,ENGINE | Motor seized at 52,000 miles.... replaced motor... at 72K miles, lifters and rods had to be replaced on the 2nd motor. Transmission also failure at 72K, being replaced. | Crash: No Fire: No | Unknown |
| Jan 2025 | ENGINE,FUEL/PROPULSION SYSTEM | On January 8th I was driving when my 2020 GMC Sierra 1500 Denali started to misfire as well as several warning lights blinking. I happen to be a couple miles from the dealership I purchased it at so I drove it straight there. A few days later I was notified it was the lifters that went bad and it would cost $5400 plus tax. This is disturbing since I have only had my truck for a little over 4 years with 68,000 miles on it. After researching the problem it appears that its a common issue and I notices a class action lawsuit for this reason. Since it's not recalled currently I'm stuck covering the invoice. Before the problem happened my truck was driving normal and no warning lights came on. This needs to be investigated so the consumer isn't stuck paying for something that is an obvious GM issue . | Crash: No Fire: No | Unknown |
| Jan 2025 | POWER TRAIN | The contact owns a 2020 GMC Sierra 1500. The contact stated that while accelerating from a stop light, the rear wheels seized. There were no warning lights illuminated. The vehicle was diagnosed by a mobile mechanic with transmission failure. The vehicle was towed to the residence. The dealer was informed of the failure. The contact was informed by the dealer that the repair was not covered under warranty due to the mileage. The vehicle had not been taken to the dealer. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was 82,000. The VIN was not available. | Crash: No Fire: No | 82,000 |
| Jan 2025 | POWER TRAIN | See attached document for complaint. | Crash: No Fire: No | Unknown |
| Jan 2025 | ELECTRICAL SYSTEM,FORWARD COLLISION AVOIDANCE | Driving down highway at 60 mph and truck shut off. had to try to get it over to the shoulder to off the travel lane. Dealer found wire harness chaffed at front left shock tower ECM bracket. Several wires damaged, repaired and cleared codes. This could have been much worse had I been in heavy traffic and needed to cross additional lanes of traffic to park in a safe area. I had no power steering and limited space to park the truck. I called to police to have a car dispatched to park behind me so the truck could be loaded on a tow vehicle to bring it to the dealer. This could have been worse had my wife been driving. | Crash: No Fire: No | Unknown |
| Jan 2025 | POWER TRAIN | The truck was dropped off on November 11th of last year due to a valve body failure, and I’ve been informed that repairs cannot be completed because the necessary parts are unavailable. I purchased the truck in late August of last year and am now stuck making payments on a vehicle I can’t even drive. When I approached the GMC dealer about trading it in or having them buy it back, they said trading it in was an option but couldn’t offer anywhere near what I paid. To make matters worse, they have no timeline for the repairs, and buying it back isn’t an option. | Crash: No Fire: No | Unknown |
| Jan 2025 | LANE DEPARTURE | ADDITIONAL INFORMATION RE ODI 116346689: Tried to report to GM using 800-462-8782 provided by you. Agent would not accept ANY information that I tried to provide, including year/make /model and would not confirm or deny that the issue was known by them. Agent said that the dealer would report their inability to fix the issue directly to GM, and that I could not. I have no way of knowing if the dealer made this report to GM. Calling this number was an infuriating, complete waste of time. | Crash: No Fire: No | Unknown |
| Jan 2025 | ENGINE,FUEL/PROPULSION SYSTEM | I had Engine Failure in June 2024 with roughly 50,000 miles. I was getting on I75 North in Auburn Hills, MI, when I heard a loud pop. The vehicle began shaking violently with a loss of engine power warning displayed, loss of oil pressure displayed followed by 2 successive limp mode warning. The vehicle would not drive over 25 MPH. Luckily the next exit was only a mile down the road. I was able to drive on the shoulder of the Interstate to get off of the highway. When I parked the vehicle shortly after, I viewed oil spewed all over the engine bay and under the truck. I then waited 4 hours in 95+ heat for a tow truck. The engine was replaced by the dealer with no root cause identified or communicated to me. There were no warning prior to this failure. The vehicle has had over 13 warranty related issues including the DEF heater melting, CAC pump failure, Numerous Exhaust Leaks, NOX and EGR sensors failing, brake control module faults etc. | Crash: No Fire: No | Unknown |
| Jan 2025 | STEERING,ELECTRICAL SYSTEM,ENGINE | On [XXX], I was driving my truck on [XXX] through Phoenix, AZ. It was 5 days after I had purchased the vehicle and only had 250 miles on the odometer. I was in the left lane was traveling at approximately 75mph. Within the span of about 20 seconds, several lights on the dash annunciated and several messages including a message about a brake failure and steering assist failure and then the engine suddenly turned off. The steering seemed heavy and the brakes seemed less responsive. I was able to coast to a stop on the side of the road thanks to the help of a couple truckers who blocked traffic across multiple lanes. The truck was towed to the dealer and they told me the entire engine needed to be replaced. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |