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 156
POWER TRAIN 53
ELECTRICAL SYSTEM 39
SERVICE BRAKES 25
STEERING 19
UNKNOWN OR OTHER 18
FUEL/PROPULSION SYSTEM 11
ENGINE AND ENGINE COOLING 10
SUSPENSION 9
VISIBILITY/WIPER 7
436 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| Jan 2026 | ENGINE | When driving at about 30 mph the truck randomly shut off and would not start or try to start. I was later told the engine crankshaft rod bearings seized. | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | Truck started to vibrate and loud tick sound, CEL for misfire and traction control. Hard shifting until I could pull to a safe area to call for a tow. Around 76k miles on the truck when it happened. | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the engine seized. No warning lights were illuminated. The contact disabled the stop-to-start feature, and the failure ceased. The vehicle was taken to the dealer, and the contact was informed that the repair was not covered under recall. In addition, the contact was informed that the vehicle needed to remain with the dealer for two weeks while performing diagnostic tests on the vehicle. The contact was unable to be without a vehicle for two weeks. The vehicle was the only means of transportation. The contact stated that the failure was a known failure with the vehicle and that the manufacturer needed to repair the vehicle. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was made aware of the failure, and a case was filed. The contact was informed that the repair was not covered under the recall. The contact was advised to take the vehicle to the dealer for a diagnostic test. The failure mileage was approximately 123,000. | Crash: No Fire: No | 123,000 |
| Jan 2026 | UNKNOWN OR OTHER | Transmission 10l80 stuck solenoid truck has hesitation delayed shifting. And will not shift after certain gears. | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | Sudden engine issue. Knocking, power loss, brake and steering warnings. Severely damaged engine. Mechanic says 2 cylinders are irreparably damaged and entire engine must be replaced | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | Driving to the lake on the highway towing a trailer, a loud tapping noise started followed by vibration. Engine seems to have lost power during acceleration. | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | My 2020 gmc sierra has had poor gas mileage problems i have taken it to gm a few times with them not able to dind anything wrong through diagnostic. A couple years later my horrible gas mileage came back and service ecs and stabilitrack message came back on and disappeared. I spoke to another shop and they advised me its the dfm lifter issues that everyone has been talking about. So the shop performed the well know fix and has fix the issue. A month after now the valve body gave me a p2817 code showing that the solenoid is stuck in the off and was also advised that this is a know issue being addressed. Currently the truck is in the shop. When is enough enough with all the issues across the nation whwn is gm going to make it right | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | MY 2020 GMC SIERRA DENALI EXPERIENCED A COMPLETE ENGINE FAILURE in June of 2024. Dealer repair was in excess of $7,700.00. They stated they knew this was going to happen at about the 70,000 mile mark as they have fixed many in that same time. Repair resulted in rod replacement and cam shaft damage and replacement. | Crash: No Fire: No | Unknown |
| Jan 2026 | POWER TRAIN | The contact owns a 2020 GMC Sierra 1500. The contact stated that while his wife was driving at an undisclosed speed, the vehicle jerked violently. The driver stated that the vehicle failed to respond as intended while depressing the accelerator or brake pedal. The check engine warning light was illuminated. The driver was able to pull over to the side of the road. The vehicle stopped jerking while driving but failed to exceed 30 MPH. The driver pulled into a parking lot and parked the vehicle. The contact was made aware of the failure and went to the parking lot. The vehicle was restarted and jerked abnormally. Additionally, while shifted into reverse(R), the vehicle failed to function as intended. The vehicle was taken to the dealer, where it was diagnosed, and two DTC were retrieved for unknown transmission software failure, and it was determined an unknown part in the transmission had failed. The dealer informed the contact that an unstated recall was closed. The vehicle remained at the dealer unrepaired. The manufacturer was made aware of the failure, a claim was filed, and the contact was informed that the recall was closed. The failure mileage was approximately 146,000. | Crash: No Fire: No | 146,000 |
| Jan 2026 | POWER TRAIN | I was driving my vehicle on the highway when the transmission suddenly gave out with no warning whatsoever. When I say gave out, I mean, it just completely stopped working and was unable to go into any gear. I was luckily able to coast over to the median without an accident occurring, but it was not without much concern or worry as traffic moving on the highway is 70 miles an hour plus and quite full of vehicles .I consider myself lucky that I have extensive driving experience and was able to conduct myself calmly under the circumstances. It was a bit tricky, getting situated though under those circumstances. There was no advanced warning in anyway. no engine lights, no sounds ,nothing. This is a well maintained vehicle. All my service is done by the dealership, and I have never been given any indication that there was something wrong. However,After this happened, I have been researching and found that many of these vehicles with this transmission continue to have this problem. This is not normal wear and tear or normal mechanical failure. I have owned many vehicles and never felt as unsafe as I did in that moment, or had a vehicles transmission fail so abruptly.For me, and the research I have done, I can only hypothesize the materials and engineering involved with this transmission are inherently inferior, completely faulty, and a safety risk/hazard to anyone who owns or operates the vehicle. I consider myself lucky to walk away unscathed, other than the economic price that it is going to incur on my finances for repairs.I would hope that it doesn’t take something serious to happen before someone takes action and conducts a recall of this product. From what I have read and what I have experienced, this is truly an unfortunate accident waiting to happen and it appears nothing is being done. I truly hope that you could take a little more look into this matter. Thank you for your time and energy. I have already contacted the manufacturer and felt ignored. | Crash: No Fire: No | Unknown |
| Jan 2026 | POWER TRAIN,ENGINE | My 2020 GMC Sierra with a 5.3L engine and 78,272 miles on the vehicle, experienced damaged lifters which also resulted in a damaged cam shaft. The total repair bill was $9,208.86. While in the GMC dealership for repair, there were 2 other trucks - same model, same year, same engine - in for the same repair. When searching on-line, I found the recall for the GMC 6.2L engine for similar issues. It is my opinion that the 5.3L engine is experiencing the same types of issues. I have driven GMC trucks for almost 40 years and have never experienced these types of issues. I have been told by several people that it is related to the Dynamic Fuel Management system and to fix the problem to disable the system to keep the truck in V8 mode. There are several solutions on line to make this happen. I am no engineer and only provide this as background information. From my perspective, it is clear that GM has a problem (whatever the root cause) with their 5.3L engines. | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | We were driving down the interstate at about 75 mph when a message came up that said to shift to neutral and push the start button. My husband did and it continued to drive perfectly fine, but about 6 miles down the road it did the same thing again except when he pushed the start button it did not start. I cannot begin to tell you the cause as to why it would’ve been doing that as I have never had any other issues with it. | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE | Bought the truck less than four months ago and as of yesterday it consumed a substantial quantity of oil and later refill. However today it made a noticeable noise until it shut off permanently. Dealer did not disclose this | Crash: No Fire: No | Unknown |
| Dec 2025 | ENGINE | I started to notice changes in performance around 75k miles. Seemed like performance was subpar compared to what was the norm. Seemed to lose some power. Minimal at first, more so just recently around 90k. Oil consumption was starting to accelerate at each oil change at 75k, 80k, 85k, 90k. To the point around 85k and 90k that I would not go over even 1 mile from the 5k threshold without changing the oil. Around 90k I could tell it was not getting any better, deficiencies were accelerating it seemed. At 91k miles I started to hear clicking noises and loss of power, starts were getting rough, bouncing at idle. I stopped driving it, only driving it to the dealership where I brought for a look at it. Will be driving it again for them to do a deeper diagnostic. Many misfires at cylinder 5. PO305 the issue. Showed up around 91k miles on 12/17/25 Now investigation into my model. I see online. | Crash: No Fire: No | Unknown |
| Dec 2025 | ENGINE AND ENGINE COOLING,ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving approximately 35 MPH, the vehicle lost automotive power with the check engine warning light illuminated and the message "Vehicle Might Lose Power" displayed. The vehicle remained at the residence, and the contact used a self-diagnostic tool to retrieve a fault code related to the coolant valve D. The contact determined that the coolant valve D needed to be replaced. The vehicle was taken to an independent mechanic; however, the contact was unaware of the part that needed to be fixed in the vehicle. The vehicle was repaired. The contact researched and was made aware of an unknown NHTSA Campaign Number; however, the VIN was not under recall. The manufacturer was contacted and confirmed that the VIN was not under recall. The failure mileage was approximately 31,000. | Crash: No Fire: No | 31,000 |
| Dec 2025 | ENGINE | Fuel management system caused a lifter to fail (stuck) which resulted in camshaft damage at 77,611 miles. GM refused to cover the repair, although there is a pending class action lawsuit against GM for this very issue. Truck was repaired at a GM dealership - Sunrise Collierville, TN. Repair costs was approximately $7,000. This occurred during a 2.5 hour road trip which put lives at risk. The truck began to vibrate, and the check engine light came on. There was no other warning before the failure occurred. No police or insurance were involved. This occurred on 9/27/25. It took the dealership 32 days to diagnose and repair the issue. Thanks. | Crash: No Fire: No | Unknown |
| Dec 2025 | POWER TRAIN | While driving on the interstate at 70 mph, the transmission began to shudder. It continued the duration of the trip of 90 mins. Following day, the transmission is continuing to shudder and is now shifting hard. | Crash: No Fire: No | Unknown |
| Dec 2025 | ELECTRICAL SYSTEM | The morning of December 12th, 2025 I used my vehicle to transport my daughter approximately 5 miles round trip from our home to drop her off at daycare and then I returned home. I used my front and rear defrost elements to expedite removal of heavy condensation which had formed on all windows overnight. This was approximately 7 AM. I parked my truck in the driveway and went inside until approximately 11:45 AM when I went to leave in my truck and noticed the rear sliding window had shattered. The window shattered and distributed tempered glass fragments all over the inside of the cab. Only approximately 10% of the window remained intact. I then reviewed the security camera footage from my driveway and discovered that the window failed entirely on its own with nothing hitting/striking/touching the window, nor any humans or animals in the vicinity. I attempted to take the vehicle to a GMC service department this morning (Dec 13) but due to their demand to keep the vehicle for 2-3 days to investigate yet unable to provide a loaner vehicle, I was unable to leave the vehicle in their possession and returned home. I plan to continue to contact GMC dealership service departments in hope I can find one which can provide a loaner vehicle, as I will need transportation to and from work in the coming days. I do have video footage of the incident although I am unable to add it below. | Crash: No Fire: No | Unknown |
| Dec 2025 | ELECTRICAL SYSTEM | The contact owned a 2020 GMC Sierra 1500. The contact stated that after the vehicle was purchased and while driving at an undisclosed speed, the check engine warning light illuminated. The dealer was contacted. However, the check engine light turned off, and the dealer refused to inspect the vehicle. The contact stated that while driving at an undisclosed speed, the vehicle jerked and the check engine light illuminated. The dealer was contacted. However, the warranty had expired, and the dealer refused to inspect the vehicle. The manufacturer was contacted, and the contact was offered a five-hundred-dollar coupon. The vehicle was taken back to the dealer. However, no cause for the failure was found. The contact stated that an unknown part was replaced. The contact stated that the failure persisted. The contact stated that while turning on the engine, the contact's sister informed him that smoke was emitting from under the hood. The contact turned off the engine, opened the hood, and noticed that all of the wires were melted. The contact splashed water on the wires. The contact checked underneath the vehicle and noticed that the plastic that was burnt was leaking residue. The vehicle was left at the residence where the contact's mother lives. The next day, the contact noticed that the front windshield had shattered due to the heat from the burnt wires. The insurance company was notified and referred the caller to take the vehicle to be inspected. The vehicle was towed to a collision center. The contact was informed that the vehicle had a factory defect. The vehicle was not repaired. The manufacturer was notified of the failure. However, no assistance was provided since the warranty had expired. The failure mileage was approximately 32,000. | Crash: No Fire: Yes Towed | 32,000 |
| Dec 2025 | ENGINE | In December of 2023 my 2020 GMC Sierra 1500 was driving down the freeway, experienced a jerking and low oil pressure. Pulled over and shut vehicle off and wouldn't turn back on, engine locked up. The vehicle received a brand new 6.2l replacement motor in April of 2024- $15k in parts and labor. This vehicle was not included in the recent recall, but obviously experienced a similar issue. This was at 75k miles. The car was owned by a different owner at the time of the engine failure. I bought the vehicle as a repo and proceeded to get the engine fixed on it. | Crash: No Fire: No | Unknown |
| Dec 2025 | ENGINE | Engine lost all power while driving highway speed. Vehicle towed to Cavender Chevrolet dealer in Boerne, TX. Dealer inspected and determined cam bearings damaged. Engine replaced with remanufactured engine. | Crash: No Fire: No | Unknown |
| Dec 2025 | POWER TRAIN,ENGINE | MY 2020 5.3 L GMC AT4 IS EXPERIENCING LOSS OF POWER WITH BUCKING & STALLING. CYLINDERS ARE NOT ACTIVATING WHEN CALLED CHECK ENGINE LIGHT IS FLASHING, IT STARTS ROUGH AND MAKES NUMEROUS NOISES AT VARIOUS SPEEDS, AS WELL AS AT IDLE. SO I BROUGHT MY VEHICLE TO MY LOCAL AUTO REPAIR SHOP. OUR MECHANIC FOUND TWO FAILED FUEL INJECTORS AND A FAILED THROTTLE BODY. THEN THE LOUD KNOCKS IN MY BLOCK FAILED AN ACOUSTIC TEST. HE ALSO DETERMINED THE LIFTERS, PUSH RODS AND CAMSHAFT ARE EXPERIENCING EXCESSIVE WEAR. THE AFM SYSTEM HAS FAILED! HE WARNED ME THAT FURTHER USE OF MY MOTOR (WITH ONLY 42K MILES ON IT) WILL CAUSE A CATASTROPHIC FAILURE. MY RESEARCH SHOWS THAT THESE ISSUES ARE BECOMING COMMON OF 5.3 GMC MOTORS. WE SEARCHED THE COUNTRY FOR A REBUILT MOTOR AND FOUND THAT NONE ARE AVAILABLE FOR THE NEXT SEVERAL MONTHS. HOWEVER, I WAS ABLE TO FIND A NEW MOTOR AT MUCH GREATER COST. GMC HAS DECLINED ASSISTANCE AT THIS TIME. MY VEHICLE HAS NO VALUE AS IS, SO I ORDERED THE NEW GM ENGINE. WITHOUT THE DOD SYSTEM, THESE ENGINES WERE DESIGNED TO GO WELL OVER 100,000 MILES. I AM A FAITHFUL GMC OWNER AND NONE OF MY PREVIOUS GMC TRUCKS (2003, 2013, 2015, 2019) HAD SUCH A MAJOR PROBLEM. NOW THE 2020'S FUEL SAVING SYSTEM HAS FAILED AND REQUIRES REPAIRS THAT AMOUNT TO HALF THE VALUE OF MY TRUCK. WHEN A FULL SIZE TRUCK STALLS ON THE HIGHWAY IT'S CERTAINLY LIFE THREATENING. | Crash: No Fire: No | Unknown |
| Dec 2025 | ENGINE | Driving on the Highway, the engine shuttered, but kept going. When I had to slow down, the engine stalled and would not restart. It left me in the center lane of a three lane highway. I was able to push the vehicle off to the side of the road. Very dangerous. No warning lights came on, no alerts. I had the truck towed to Folsom Buick & GMC in Folsom CA where the diagnosed a complete engine failure. The have now had my truck for a full month. They are trying to get GMC to share the cost of the replacement motor. In the meantime, I'm renting a pickup truck so I can continue to work. | Crash: No Fire: No | Unknown |
| Dec 2025 | POWER TRAIN,ENGINE | Ticking noise coming from engine slight metallic noise as well. RPMs drop and when they drop, you can feel power loss constant hunting in the RPMs. Also a weird vibration, not all the time in the front end somewhere. | Crash: No Fire: No | Unknown |
| Nov 2025 | SERVICE BRAKES, HYDRAULIC,ENGINE AND ENGINE COOLING | The contact owns a 2020 GMC Sierra 1500. The contact stated while driving 45-50 MPH, the check engine warning light and the brake warning light illuminated. Additionally, the contact heard an abnormal sound coming from the engine, and the vehicle decelerated. The vehicle was taken to the dealer, where it was diagnosed and determined that all the engine lifters and the camshaft needed to be replaced. The vehicle was repaired. The contact related the failure to NHTSA Action Number: EA25007 (Engine and Engine Cooling). The manufacturer was notified of the failure and informed the contact that the VIN was not under recall. The manufacturer offered to partially cover the cost of the repair. The failure mileage was 107,787. | Crash: No Fire: No | 107,787 |