GMC Sierra Complaints (2020)

626 consumer complaints on file.

#11703500December 7, 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
Injuries:
0
Deaths:
0
#11703546December 7, 2025
ENGINE
Catastrophic engine failure after taking it in for the April 2025 recall. Complete engine replacement needed
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11703015December 4, 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
Injuries:
0
Deaths:
0
#11702228December 1, 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
Injuries:
0
Deaths:
0
#11702341December 1, 2025
ENGINE, POWER TRAIN
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
Injuries:
0
Deaths:
0
#11701487November 25, 2025
ENGINE AND ENGINE COOLING, SERVICE BRAKES, HYDRAULIC
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
Injuries:
0
Deaths:
0
#11701589November 25, 2025
POWER TRAIN, ENGINE
-lifter failure on 6.2 v8 engine, causing damage to camshaft -lost significant propulsion while driving on the highway, nearly avoided being rear-ended by another vehicle due to loss of vehicle propulsion -dealer had to to replace lifter bank and camshaft -no issues, once lifter failed dash lights all lit up
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11701143November 24, 2025
ELECTRICAL SYSTEM, VISIBILITY/WIPER, STRUCTURE:BODY
The rear defroster massively overheated. It started heavily smoking and eventually exploded the rear windows. Only warning sign was the smoke which we noticed quickly because the windows were up. Had the windows been down we might not have noticed before a fire started. I'm taking it to a dealership now. This module also triggers on from a remote start. Extremely dangerous!!!
Crash:
No
Fire:
Yes
Injuries:
0
Deaths:
0
#11701366November 24, 2025
ENGINE
Engine fan has been constantly running, with engine temp reading around 230 consistently. After driving 5 miles on the interstate it shot up to 260 and said “engine temp overheating, idle engine”.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11700944November 22, 2025
ENGINE
I am Having direct issues with the engine when the vehicle is started and continues while idling or driving at any rate of speed.There's a continuous "Knocking" noise that has concerned me for a while now. My vehicle (2020 GMC Sierra 6.2 liter gas engine) with almost 100,000 miles has been doing this for a while now (at approximately 50,000 miles) and (was documented at the dealership when I made a complaint which included what I considered the vehicle to be using/losing more "oil consumption" than the normal 3-4 quarts between oil change) dating back to 2022 0r 2023 when I was told by the dealership that the amount of oil being used/ lost still fit within the manufacturers specifications.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11700611November 20, 2025
POWER TRAIN
My truck had engine failure while at the dealership getting new tires installed on 11/12/2025. When they started my truck they detected major knocking in my engine the 1st thing in the morning. It unsafe to drive they're telling me my engine needs to be replaced. My engine has 58,000 miles on it. There was no issues with my truck when I drop it off.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11700403November 19, 2025
UNKNOWN OR OTHER
Safety Recall N242454440 Momentary Rear Wheel Lock-Up was issued for 2020 to 2022 GMC Sierra 1500 but mine is not included. I drive a 2020 GMC Sierra 1500. It is experiencing harsh shifting and now there is a feeling in the rear wheels like they are trying to get stuck or hang up. Why is my truck not included?
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11700257November 19, 2025
ENGINE
My 2020 GMC Sierra 1500 Denali with the 6.2L L87 V8 just began experiencing a new rough idle with intermittent RPM dips. There are no engine codes or warning lights. Idle drops are noticeable, suddenly began this week. I am concerned due to ongoing NHTSA Engineering Analysis EA25-007 involving this engine. Some owners reported engine failure with little warning. The truck has right over 68,000 miles on it and has had every oil changed performed at a GM dealer. I have had to top off the oil between cycles and always used the recommended oil, being the Dexos Gen 3 due to the truck burning a small amount of oil. More detail on a possible cause. I believe it would be worth investigating the DFM technology. I will be performing a fuel cleaner and possibly a lifter cleaner and/or additive. I would like to tune the truck and turn off the DFM since this is what I have read causes the truck to burn oil and damage the lifters. However, I will wait until this Analysis is completed before deciding to change the truck's stock tunes.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11700312November 19, 2025
ENGINE
The engine failed and started burning oil at a rate of 3 quarts every two weeks. The vehicle is currently at the GMC dealership having the engine rebuilt at a cost of over $15,000. The vehicle has approx. 116,000 miles at time of failure, so it is outside of the manufacturers warranty. The GMC dealership (Fred Anderson Greer) has photos. The engine is a 6.2L but not currently under recall as it is a 2020, the recall includes 2021 - 2024 models.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11700178November 18, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2020 GMC Sierra Denali. The contact stated that while stopped at a traffic light with the brake pedal depressed, the vehicle shut off unexpectedly. There was no warning light illuminated. The contact made several attempts to restart the vehicle; however, the vehicle failed to restart. Due to the failure, the vehicle was towed to the dealer where a diagnostic test was performed. The contact was later informed that the engine had seized due to engine bearing failure, and the contact was provided an estimate for a new engine. Upon investigation, the contact discovered NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling) and linked the recall to the failure. The manufacturer was notified about the failure and the recall, and the contact was informed that the VIN was not included in the recall. The vehicle was not repaired and remained with the dealer. The failure mileage was approximately 190,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11699863November 17, 2025
ENGINE
This is the 3rd catastrophic engine failure since purchasing this new vehicle from the dealership, the vehicle is currently at the dealership and is available for inspection. The latest diagnostic report has been attached from the dealership for reference. My safety and the safety of others was at risk with each occurrence. The 1st occurred on the interstate when a lifter rod bent causing loss of power with no warning, engine was rebuilt by the dealership. The 2nd occurred on the interstate when a different lifter rod bent causing loss of power with no warning, engine was rebuilt again by the dealership. The 3rd occurred just recently while on a highway. The engine suddenly turned off with no warning. The dash told me to put it into neutral and start again. I had to coast the truck for a long distance after the sudden loss of power in order to attempt to restart the engine. The engine would not start. The diagnostic report from the dealership states "engine is seized tight, maxi fuse is blown, needs engine replacement."
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11699884November 17, 2025
ENGINE
My engine is currently being torn down at the dealership.I heard a ticking noise coming from my engine so I took to the dealership I bought it from and when they did their diagnostics and inspection they said it was a connecting rod bearing failure.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11699612November 15, 2025
SERVICE BRAKES, POWER TRAIN, ENGINE
First my torque converter went out, no warning lights only shaking wehn shifting, I got it replaced already it cost me $2400 Second Warning light service for Brakes, Traction and power steering come on and off. And sometimes truck doesn't brake well and steering wheel feels hard to drive, it has happened while on expressway with family. Third Engine oil low Add oil warning sign comes up alot and I have to add oil, engine has a rough idle now, also when I turn truck on smoke comes out while having a rough idle, recently it started knocking, I haven't moved the truck since than
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11698923November 12, 2025
ENGINE
This is a report on an incident that happened a year ago. Vehicle was taken to GMC dealer who replaced the engine at our expense. Seems to be consistent with the problem on newer GMC's that have been covered by a recall. This 2020 is one of three GMC's owned by our company. This expense was in the $12,000 range. (The 2019 experienced similar issues in 2022 and the expense was $2800 ish, and in 2024 another $1200 ish. ) Dash lit up like a Christmas tree, all warning lights on. Stalled, barely moved.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11698523November 10, 2025
ENGINE
Engine ticking especially when cold, dealership claims they fixed it while it was under warranty but it has continued to do it.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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