Complaint volume
425 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
425 consumer-submitted complaints on record for the 2020 GMC Sierra, grouped by component category.
425 Total complaints
11 Crash reports
4 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, 4 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 118 complaints, with an average reported failure mileage of 44,233 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
4 Fire
6 Injury
0 Fatality
28 Towed
4 Medical attention
What are the most common 2020 GMC Sierra complaint categories?
ENGINE 125
POWER TRAIN 36
ELECTRICAL SYSTEM 21
POWER TRAIN,ENGINE 17
SERVICE BRAKES 16
STEERING 14
UNKNOWN OR OTHER 14
ENGINE AND ENGINE COOLING 9
SUSPENSION 9
ELECTRICAL SYSTEM,ENGINE 8
425 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| Mar 2025 | ENGINE | At 59000 miles my lifters were rebuilt on the 6.2 liter engine because of a failure in the 1 and 3 piston. Gm paid for the repairs and then At 79000 miles the motor completely blew resulting in complete failure and seizing the motor and heavy metal chips were reportedly found in oil pan. Gm claimed it was a result of me not doing regular oil changes however I suffer from OCD and I am automotive engineer and my oil was changed early in most cases with my truck. Gm will not take responsibility and at the time they wanted $16k to fix my truck. I was going through a very tumultuous divorce and had to pay atty $34k for that wnd could not pay $16k for a new engine resulting in me having to give my truck back to bank and I have not been able to buy a truck or vehicle since then as it ruined my once perfect credit of 820. It’s changed my life forever and GM should take responsibility. I will never buy another GM product again and my father worked for them my whole life and my family only drove their products. | Crash: No Fire: No | Unknown |
| Mar 2025 | ENGINE AND ENGINE COOLING | The contact owns a 2020 GMC Sierra 1500. The contact stated while driving 70 MPH, the low oil pressure warning light illuminated. The contact pulled over to the side of the road and noticed that the oil level was abnormally low. The contact added oil to the vehicle and continued driving. The vehicle was taken to Mike's Garage, where it was diagnosed that the valve cover was fractured; however, the part to repair the vehicle was on backorder. The contact related the failure to TSB Number: 22-NA-027. The dealer was notified of the failure and informed the contact that the vehicle was not covered under the TSB. The vehicle was not repaired. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was approximately 96,000. | Crash: No Fire: No | 96,000 |
| Mar 2025 | ENGINE | The Lifter failure, bent rod, and basically ruined the the cam shaft, the vehicle has had engine replaced and the current engine is now acting up. once again. | Crash: No Fire: No | Unknown |
| Mar 2025 | UNKNOWN OR OTHER | Shift to park message appears when in park and engine is turned off. Transmission control had an internal circuit failure. Park not fully engaged and vehicle could roll. Problem confirmed by dealership. Prior recalls for earlier gmc models but not my year. | Crash: No Fire: No | Unknown |
| Mar 2025 | ENGINE | While driving our 2020 Sierra AT4 down the highway at 65 mph, the engine suddenly cut out and started sputtering. Every light came on. We pulled off the highway and had the truck towed. Our highly trusted, family mechanic company diagnosed lifter 5 was twisted and stuck, along with another stuck lifter. The cost to replace the engine was one hundred dollars more than repairing the two lifters. They purchased a new engine through Van Chevrolet and were surprised the cost had recently decreased from $7-8k to $3900, to purchase a rebuilt engine. The engine appeared to be new, with the bolt threads unused. The new engine comes with a 3year 100k mile warranty through the dealership. We called GM, they said since we went to another mechanic they would not speak with us. | Crash: No Fire: No | Unknown |
| Mar 2025 | ENGINE | The engine, while driving down the road, incurred a failure to the pusher rod in the #5 cylinder. This occurred at 6750 total miles on engine. Engine failure was repaired by a dealership. The failure occurred again at 99,500 miles to the same #5 cylinder causing major engine damage leading to the replacement of the engine. Our safety was put at risk as the truck decelerated and began vibrating. The second failure occurred and the engine shutdown. These incidents occurred without warning, Yes, a dealer was involved in both incidents. Only a dealership has been involved. The warning occurred after the failure. | Crash: No Fire: No | Unknown |
| Mar 2025 | POWER TRAIN,SERVICE BRAKES,ENGINE | -Transmission valve body Failure, Wheel lock up, ABS Event, Loud Bang and a Flashing "D" on Driver Information Center (DIC) when Lightly or Moderately Accelerating Forcing an 8-7 or 8-6 Downshift -When all four tires lock up at a high rate of speed, this puts the driver, the passengers, and all others on the road at risk for injury or death. -Yes, the problem has been found in a document by my local dealer that this issue was added to my exact vehicle's service manual on 11/27/24. The document describes in detail the exact scenario I have been involved in multiple times. It is deemed as #21-NA-275. It locks up the tires randomly to the vehicle in mid acceleration at any speed including 80 miles per hour in one instance for me. -Yes, the dealership inspected it and found the issue to correlate with the newly added section to the service manual, 13333166. This document ID is 5925530 and the added information to the dealership is #21-NA-275. The GMC manufacturer has been contacted as of 3PM MST 3/14/25. Insurance doesn't deal with mechanical problems. The police will only be involved when there is death or injury. -No. The only warning that happens is simultaneously as the vehicle locks up the tires causing the driver (me) to inevitably try to save myself and others, swerving and trying to focus on not hurting myself or others but I did notice the "D" flash on one of these occasions. This is the most dangerous issue with a vehicle I have ever even considered. At any time, for any reason, all four tires can lock up at any rate of speed and cause multiple casualties. The way to fix this is to spend $3,000 which I am sure many people like myself do not have. This means there are thousands of these exact make and models of vehicles on the road right now. Please do not take this lightly as I have almost crashed multiple times with people in my vehicle due to no fault of my own. | Crash: No Fire: No | Unknown |
| Mar 2025 | POWER TRAIN | The contact owns a 2020 GMC Sierra 1500. The contact stated while accelerating from a complete stop, the vehicle lunged forward. The contact stated that the failure recurred while driving at various speeds depressing the accelerator pedal, and while decelerating to come to a complete stop. The check engine warning light was illuminated. Additionally, the contact stated that while coming to a complete stop at a traffic light, the vehicle lunged forward violently, as if the vehicle had been rear-ended. The vehicle was taken to Quality Plus Automotive, where it was diagnosed that the transmission had failed and needed to be replaced. The local dealer, Leith GMC (919) 366-1000), and other dealers were contacted and informed the contact that an estimate for the repair could not be provided because the transmission part was not available. The vehicle was repaired by Quality Plus Automotive. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 75,450. | Crash: No Fire: No | 75,450 |
| Mar 2025 | POWER TRAIN,UNKNOWN OR OTHER | The Transmission cooler lines broke and spilled out all the oil/fluid on my 2020 GMC Sierra Elevation pick-up truck. Once all the fluid was spilled out the Sierra truck would no longer move. The Sierra truck was towed to the dealership I originally purchased the vehicle. The dealership was Cranbury Buick GMC. The dealership mentioned that the hoses broke/leaked from the crimped housing at the ends of the hoses. The dealership stated that the original OEM transmission cooler line hoses were discontinued and new OEM replacement transmission cooler line hoses were created. Please see the attached dealership bill/invoice for the parts and labor to fix the cooler line issue. I feel this issue should be a recall on all 2020 GMC Sierra trucks, especially if GM replaced the original OEM hoses with newly created OEM hoses Thanks [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |
| Mar 2025 | POWER TRAIN,SERVICE BRAKES | Vehicle shifting poorly, and I have had a bunch of brake and rotor issues. | Crash: No Fire: No | Unknown |
| Mar 2025 | PARKING BRAKE,STRUCTURE,ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the parking brake independently activated. In addition, the contact stated that the vehicle had an oil leak from the oil pan. The contact stated that the oil needed to be added every two days. The contact stated that the alert system warning light was illuminated. The vehicle was taken to the dealer; however, the failure was not duplicated. The contact was informed that the failure could not be duplicated, because no active codes were retrieved. In addition, the contact stated that the frame had corrosion. The vehicle was taken to the dealer for the corrosion failure, however the contact stated that the previous dealer had failed to help. The dealer confirmed the corrosion; however, the vehicle was not repaired. The manufacturer was made aware of the failure but provided no assistance. The contact was advised to contact the NHTSA Hotline to report the failure. The failure mileage was approximately 10,000. | Crash: No Fire: No | 10,000 |
| Mar 2025 | ELECTRICAL SYSTEM | Had GMC (Leominster, MA), perform the safety recall for the transmission on my Sierra. This is the one for the rear wheel lockup that requires a software update. My battery was completely dead after the vehicle sat for a week. No accessori s plugged in, and it's a 6 month old battery Battery tested fine and is charging now, but it appears the CPU never fully powered down after the software update, resulting in needing multiple jump starts and 3+ hours of run time to charge the battery enough to turn over on its own. I can see this being a safety issue in relation to the Auto-start, because when it is being used, the battery is needed to restart the engine. This could result in a stall at an intersection, and if drivers are not alert, may collide with a stalled vehicle. | Crash: No Fire: No | Unknown |
| Mar 2025 | POWER TRAIN,ENGINE | Lifters failed and cam shaft was busted. Standard issues with 6.2L engines. Was traveling down highway and vehicles was shaking violently. Inspection report available. Has been inspected by GM service center. No symptoms or warnings prior to failure. | Crash: No Fire: No | Unknown |
| Feb 2025 | ELECTRICAL SYSTEM | While driving on interstate transmission would “lock up” momentarily creating drastic drop in speed and unable to shift gears and accelerate. “D” would start flashing in dash board. Dealership said this is unrelated to current recall about rear wheels locking up from valve body failure and instead this is an electrical issue. Dealership also stated this is the 2nd truck in a week they have had come in with this issue. Almost caused accident on interstate with my family and I as a result of sudden drop in speed and unable to accelerate with multiple cars behind us. | Crash: No Fire: No | Unknown |
| 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 | 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 | 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 |