Complaint volume
424 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
424 consumer-submitted complaints on record for the 2020 GMC Sierra, grouped by component category.
424 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
424 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| May 2026 | ENGINE | My engine suffered an internal catastrophic event, and needs to be replaced | Crash: No Fire: No | Unknown |
| May 2026 | ELECTRICAL SYSTEM | 2020 GMC sierra 1500 infotainment system including navigation,OnStar and voice command, stoped working on Friday May 15th with no prior warning. These systems are integral for modern safe travel and severely affects the value and driver confidence in the vehicle. It seems to be running mechanically sound but, with some of the communications and information systems not working properly I am unsure how much of the info is incorrect like the clock (which can not be set manually). I have scheduled an appointment with the dealer for June 2nd the earliest date available. | Crash: No Fire: No | Unknown |
| May 2026 | ENGINE | Good evening, I want to formally document what happened today regarding my GMC Sierra after I brought it to the dealership on Friday morning for transmission concerns that I had already reported. At that visit, the vehicle was inspected, and I was informed that the truck was still safe to drive while waiting for the extended warranty approval for the replacement parts that were needed. Unfortunately, today my family and I experienced a very serious and frightening incident on the expressway. While driving, the truck suddenly lost power, barely moved forward, and began shaking violently. We were placed in a very dangerous situation in traffic and struggled with great difficulty and fear just to make it home safely. Once we arrived home, the vehicle completely shut off and would not restart again. This situation was extremely alarming, especially because I had already reported the transmission problems and trusted the guidance given to me that the vehicle was still drivable. My family’s safety was put at risk, and I need this matter to be treated with urgency and seriousness. Please advise immediately on the next steps regarding the vehicle, towing assistance if necessary, and how this situation will be properly addressed. Thank you. | Crash: No Fire: No | Unknown |
| May 2026 | STEERING | A known problem with these trucks is ground strap failure. I was driving and all the sudden lost power steering which almost caused an accident. There is a customer satisfaction program N252515590 that covers 2019-2024 trucks but mine was not included in this for some reason. I did have the truck fixed a my cost and was looking to get my money back from GM. I'm not sure if you can help with this but wanted to make a report that is happening with more trucks then they are fixing. If you need any other info from me please let me know | Crash: No Fire: No | Unknown |
| May 2026 | ENGINE | Sitting at a red light and when the light turned green, the engine made a noise and lost power while trying to cross the intersection. The check engine light came on along with some other lights. It was then towed to a mechanic and the engine had to be replaced due to failure of the lifters. The mechanic said it is a common issue with the GM 5.3 engine but unfortunately their has not been a recall. | Crash: No Fire: No | Unknown |
| May 2026 | ENGINE | 6.2L V8 engine. 2020 build, GMC Sierra 1500 series. Same engine in the existing recall for 2021-2024 models. Received a call from the service department of the dealership that after changing the oil and restarting the truck to reset the oil change indicator the engine shut down. Assistant service manager, Stephen Poulson [XXX] ) called and provided information that the engine seized and that the technician cannot manually forward or reverse the engine with a breaker bar. According to the technician, this is indicative of a catastrophic failure consistent with the existing recall. The vehicle is currently at Carr Vancouver Buick GMC and is available for inspection. NHTSA has permission of this owner to inspect this vehicle involved if they choose. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |
| May 2026 | ENGINE | 2020 GMC Sierra 1500 began experiencing a slight knocking sound - mechanic diagnosed as a crankshaft issue. As of last night, 5/10, the truck's knocking sound got extremely loud, the exhaust pipe emitted smoke, and the truck began "bucking." No warning messages or lamps appeared. | Crash: No Fire: No | Unknown |
| May 2026 | ENGINE | Complete engine failure with 62,500 miles. Truck appears to have the same problem as the 21-2024 which is currently recalled and engines are being exchanged. | Crash: No Fire: No | Unknown |
| May 2026 | ENGINE | We heard a knocking noise and took the truck to the nearest GM dealership. The engine had to be taken apart. The engine is a L87 6.2 liter V8. The GM dealership service department diagnosed camshaft damage that caused lifter failure. We have since been informed that GM has known about the failure of this engine for many years. In our case, we were fortunate that the engine did not fail when we were on the expressway. This is a huge safety issue. There were no warning lamps or messages from the vehicle, but we heard the knocking noise. We are facing a minimum of a 10,000 dollar repair and will not feel confident that this engine will not put our safety at risk in the future. We understand that the NHTSA has initiated an Engineering Analysis regarding this engine for the model years 2019 to 2021. (EA25007). We wanted you to have the information of another dangerous engine failure. | Crash: No Fire: No | Unknown |
| Apr 2026 | ENGINE | On 6/27/22 my 2020 gmc sierra 1500 at4 6.2L had lifter failure. The dealer fixed that problem and on 7/1/22 again has lifter failure. The dealer fixed that problem again. On 7/13/22 a third time engine had lifter failure again. I requested they need a different engine to be installed and GM agreed andthey install an L87 2022 engine. This engine seemed weak and not right since it was installed. On 10/13/222i took the vehicle in to the dealer with a complaint of ticking noise from engine area and complaint of shifting hard. The fix the shifting but nothing was wrong with engine according to the dealer. On 3/15/24 the noise are worse and I can smell fuel and noticed white milky residue on the oil cap plus a growling nose coming from engine. Coolant keeps going low and white smoke out the exhaust. The dealer does diagnosis and again nothing is wrong. Now starts the oil consumption testing and me letting the dealer know that I can smell oil and exhaust but they can't. On 8/29/2024 I take truck in for another diagnosis for rattle sounds I'm hearing under the hood from the engine especially when you accelerate. I pay $149.49 for the dealer to find the noise and they tell me they can't find anything, but everyone who has rode in the truck can. On 1/27/2025 I take the vehicle in again and the dealer does the valve cover leaking and replaces that is covered. On 2/3/2025 again vehicle back to dealer cause I can smell antifreeze and burning oil smell. The only thing they found was the muffler had a Lil leak so they wanted me to get it welded which i did and so can smell the oil. On 6/16/2025 I take the vehicle in for oil change and leave to go home then go to work about 95 miles or more and noticed after I parked and was working before I was going to head home there was a huge puddle of oil under the vehicle. I took pics. Found after inspecting my vehicle the oil cap was not in filer tube but instead sitting up on air shelf above radiator. Oil filter was about 3 turns loose. | Crash: No Fire: No | Unknown |
| Apr 2026 | POWER TRAIN,ENGINE | I’m scared to drive my vehicle because of the 6.2L V8 ongoing engine failures! I believe it to be unsafe for travel never knowing when the engine will fail. Now with over 1 Million failures of this engine! | Crash: No Fire: No | Unknown |
| Apr 2026 | VEHICLE SPEED CONTROL,SERVICE BRAKES,ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle decelerated to 30 MPH. The check engine warning light was illuminated. The vehicle was taken to a local dealer, where it was diagnosed, and determined that the timing belt needed to be replaced. The part was on back order. The vehicle was not repaired. The contact stated the vehicle previously experienced brake failure, sensor failure, and glow plug failure. The manufacturer was contacted, but no assistance was provided. The BBB referred the contact to the NHTSA Hotline to report the failure. The failure mileage was approximately 80,000. | Crash: No Fire: No | 80,000 |
| Apr 2026 | ENGINE | Driving on highway, engine light came on with many warning lights. Was just starting on a trip to SC then OH to help father for a surgery. Lifters went bad within fist 5-6k miles on the truck (6.2L) causing other damage to the engine such as bent rods (etc). Dealer repaired all DFM Lifters as there were failures on both sides of the engine, but it still sounds like there are issues internally. It is a 2020 manufactured in 2019, I have not had additional mechanical issues, but I have purposely not driven it as much since I feel that it is not dependable. It currently only has about 27k miles and sounds worse than my 2007 Lexus engine with 180k+ miles. I wanted to fill this out, so you have the data for the engineering investigation. | Crash: No Fire: No | Unknown |
| Apr 2026 | ENGINE | My 2020 GMC Sierra 6.2L (only 46,000 miles which is under warranty mileage criteria), suffered catastrophic engine failure while at 40 miles per hour out of no where and rolled without power for about ~60ft. Power came back on, and I was able to get closer to the dealership but again, lost all power and rolled for about 60ft again right in front of the dealership. The truck died while attempting to make a left turn (in oncoming traffic), it got going again in time to finish the turn. When I pulled into the dealership it pulled code P0016 which is the same code for the 2021-2024 recall currently for the 6.2L GM engine. I had all oil changes completed on time and can show evidence of them. Other repairs, recalls etc were completed at the GMC dealership. The 2020 Sierra 6.2L should absolutely be included on the GM recall. Same issues as 2021-2024. Funny how 2020's just reached over on time limit for warranty. The repair estimate for my truck is over $13K!!! | Crash: No Fire: No | Unknown |
| Apr 2026 | ENGINE | I took my 2020 GMC Sierra in for an oil change. The engine seized when it the technician tried to restart the car. We had it towed to GMC where they confirmed the engine seized. The oil repair shop then replaced the engine and when doing so confirmed the original threw a rod which is the same recall issue that is occurring with the 2021-2024 models. I have since taken the car to GMC for a full inspection and made additional repairs. The vehicle is available for future repairs. My safety and others are at risk as the engine could seize leaving my family stranded or endangering others on the road if the seizure occurs while driving. Yes the vehicle was inspected at the GMC dealership and the shop where the engine was replaced with another L87 engine. there was no warning the engine seized after an oil change. | Crash: No Fire: No | Unknown |
| Apr 2026 | ENGINE,ENGINE AND ENGINE COOLING | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed 60 miles away from home, the vehicle lost automotive power and stalled. The contact stated that the vehicle started smoking. Several unknown warning lights were illuminated. The vehicle was taken to a local dealer, where it was diagnosed and it was determined that the failure was due to an internal failure with the camshaft and the engine. The vehicle was not repaired. The manufacturer was contacted and referred the contact to the local dealer for assistance. The failure mileage was approximately 167,570. | Crash: No Fire: No | 167,570 |
| Apr 2026 | POWER TRAIN,ENGINE | After owning this truck a little over a year I’ve had to replace the transmission and now it’s in the because the motor sounds like a bag of marbles was put in it and the warranty company is a joke they only want to replace just the cam and lifters but yet the dealership hasn’t be authorized to go to the bottom of the motor to check it out this truck has been nothing but a lemon!!!!! | Crash: No Fire: No | Unknown |
| Apr 2026 | ENGINE | While driving on the highway, my engine failed unexpectedly and I had to coast across the highway without power. I had the vehicle towed to a GM dealership, where I was informed the failure was due to a lower-end engine issue and that a full engine replacement was necessary. I am aware of known issues with GM’s 6.2L engines and asked the dealership about the related recall. They acknowledged that the failure I experienced is consistent with the symptoms seen in the defective 6.2L engines. However, they stated that because my truck is a 2020 model, it does not fall within the affected VIN range. I ultimately paid nearly $11,000 for a new engine. Given the nature of the failure and its alignment with known issues, it is difficult to believe this was merely coincidental. I strongly believe the same defect exists in my engine, despite it not being included in the current recall range. | Crash: No Fire: No | Unknown |
| Apr 2026 | ENGINE | There is a click/ticking noise when vehicle is started. Noise gets louder and faster when accelerating. Have taken vehicle to 2 mechanic shops and been told by both places it is bad lifters and exhaust manifolds. I took this truck in because of loss of power. This issue has put me in unsafe/ dangerous positions on multiple occasions. | Crash: No Fire: No | Unknown |
| Apr 2026 | ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle went into LIMP Mode, and several unknown warning lights were illuminated. The vehicle lost automotive power. The vehicle was taken to the dealer to be diagnosed. There was a knock coming from the engine, there was fuel injector failure, a heated oxygen sensor control module Bank 1 failure, and fuel system failure. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 134,648. | Crash: No Fire: No | 134,648 |
| Apr 2026 | ELECTRICAL SYSTEM | Infotainment screen is flashing different colors and doesn’t work anymore. | Crash: No Fire: No | Unknown |
| Apr 2026 | ENGINE | When the truck was idling the dod/afm turned on and disabled a cylinder and now I’m just having codes pop up for cylinder misfires | Crash: No Fire: No | Unknown |
| Mar 2026 | POWER TRAIN | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving on several occasions at various speeds, the vehicle started shaking and slipped in and out of gear, with the message "Idle Transmission" displayed. The vehicle was pulled over and shifted into park(P) and then to drive(D). There was a loud banging sound coming from the rear of the vehicle. The vehicle was towed to an independent mechanic, where it was diagnosed with transmission failure. The contact was informed that the transmission needed to be repaired. The vehicle was not yet repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 80,000. | Crash: No Fire: No Towed | 80,000 |
| Mar 2026 | ENGINE | My engine started knocking horribly, I need to get a proper diagnosis but cannot afford to have a shop look at it. I have been building engines my entire life and am certain the rod bearings have failed. The engine has a distinct knock under acceleration, you can hear it clearly when pulling away from a stop sign for example. | Crash: No Fire: No | Unknown |
| Mar 2026 | VEHICLE SPEED CONTROL,ENGINE AND ENGINE COOLING | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at 65 MPH, the DEF tank failed. The vehicle went into three phases of LIMP Mode and the vehicle unexpectedly decelerated while driving. The DEF system service message was displayed. The vehicle was taken to the local dealer, where it was diagnosed with DEF tank failure, and the tank needed to be replaced, even though the tank was full. The part was on backorder for several weeks. The contact was not provided with a loaner. The vehicle was repaired. The manufacturer was contacted and opened a case, but no additional assistance was provided. The failure mileage was approximately 70,000. | Crash: No Fire: No | 70,000 |