2021 GMC Sierra 1500: What to check before buying
Owners have filed 420 complaints with NHTSA about this car, most about the engine, transmission, and electrical. The 9 checks below target those problems, in the order you would do them at the car.
2021- Owner complaints
- 420
- Recalls
- 6
- Crashes reported
- 5
- 2 injuries
Your inspection sheet
Tick items off on your phone at the car, or print it. Ticks stay on this device.
0/9 checked
2021 GMC Sierra 1500: inspection sheet
Paperwork and questions
Before you go, or before you touch the car0/3
Walk-around and cabin
Engine off, key in hand0/1
Cold start, engine bay, and underside
Ask the seller not to warm the car up first0/3
Test drive
At least 20 minutes, with some highway0/2
These checks are specific to this model year. For tires, body panels, fluids, and the other basics every used car needs, use the general inspection guide.
Check the odometer against these mileages
Owners report these failures starting around the mileages below. A car inside one of these ranges deserves a closer look at that part, or records showing it was already fixed.
Airbag warning light
2,000–5,600 miles
Early lifter failure
7,000–31,904 miles
Brake master cylinder failure
21,539–22,500 miles
Transmission valve body, pump failure
39,000–40,000 miles
Tailgate opening on its own
41,000–76,000 miles
6.2-liter recall engine failure
45,000–66,456 miles
Repeat engine failure
64,000–68,000 miles
Late transmission hard shifts
90,000–120,000 miles
Why these checks: what owners reported
NHTSA complaints for the 2021 GMC Sierra 1500, grouped by the part owners named. Open a row to read what goes wrong.
Engine178No crashes
Lifter failure dominates these reports. Lifters collapse or snap, pushrods bend, and some engines go on to rod or bearing damage. The engine knocks, shakes, drops into limp mode, or seizes outright, often at highway speed, leaving the truck stalled in traffic. Failures appear as early as 7,000 miles, and several owners report a second failure after a repair or replacement engine. Two reports involve fire after a catastrophic failure. Other complaints cover heavy oil burning, failed coolant control valves, and replacement engines stuck on backorder.
Nearly all of these complaints concern the 6.2-liter engine recall. Many owners received the notice but were told repair parts were unavailable. Some trucks failed the inspection and sat at the dealer for more than two months waiting on a new engine. Where the remedy was performed, it consisted of thicker oil, a new oil cap and filter, and a manual update, and owners doubt it fixes the defect. Some also report fuel economy dropping. Actual failures include heavy shaking, a check engine light, and sudden loss of power, several around 60,000 miles.
Transmission95No crashes
Rear wheels lock up for a moment at highway speed in several reports. That creates a sudden loss-of-control risk, and a transmission recall addresses it with new software. Some owners say the update made shifting worse or did not stop the lockups. The transmission also shifts hard, shudders, downshifts harshly, or quits entirely, with valve body and front pump idler gear failures near 40,000 miles and repeat failures soon after repairs. Many 6.2-liter owners describe engine failure under a recall, with replacement engines backordered. Diesel owners cite coolant control valve failures.
Electrical45No crashes
Fire is the most serious pattern here. Two trucks caught fire minutes after being parked and shut off, with one investigation pointing to the rear of the engine bay near the battery. A third fire was blamed on the trailer brake controller. Other reports describe the truck shutting off while driving, traced to chafed wiring or the battery, and the power tailgate opening on its own after moisture gets into its electronics. Owners also report a radio module failure after an over-the-air update, a dead digital speedometer, and false parking brake and ESC warnings.
Steering251 crash
Power steering assist cuts out suddenly. A Service Power Steering or reduced steering assist warning usually appears, often together with ESC and parking brake alerts, and steering becomes heavy or locks. Dealers report binding steering racks, backordered parts, and one repair quote of $5,000. Engine shutdowns at speed also take away steering and brake assist. Front suspension failures cause the worst outcomes: ball joints separate from control arms and alignment cam pins shear, and one of these failures ended in a crash. One report describes a steering shaft bolt missing, leaving the wheel spinning freely.
Brakes111 crash
Brakes fail without warning in several reports. A brake failure message appears, the pedal sinks to the floor, and one truck rear-ended another car in slow traffic. Dealers fixed these trucks by replacing the master cylinder, and in one case the brake booster too, on trucks showing between 21,539 and 22,500 miles. The electronic parking brake drags or applies on its own, wearing inner pads and rotors early and sometimes braking the truck hard at highway speed, even after a recall repair. Trailer brake controller disconnects also come up repeatedly.
Body and structure8No crashes
Most of these complaints involve the power multi-function tailgate. The inner gate drops or the whole tailgate opens by itself, while parked and in rain, and it damaged cargo equipment in one case. Owners note that a related recall covers heavier-duty Sierras but not their trucks, so repairs are not covered. Water leaks through the rear sliding window, and the dealer charges for the fix. One report describes a fractured front frame found after the truck shook violently and lost power at about 30,000 miles.
Door latches and locks6No crashes
The electronic tailgate unlatches and opens by itself, both while parked and while driving. In one case luggage fell onto the road. The failure tends to repeat, sometimes after a warranty repair to the tailgate switch, and dealers often cannot find a cause. Water gets past worn tailgate buttons and leaves them dead. Owners say their trucks were left out of the tailgate recall. Reported failures cluster between about 41,000 and 76,000 miles.
Airbags52 crashes
A Service Safety Restraint System warning flashes on and off, sometimes every few seconds. It shows up very early, on trucks with fewer than 2,000 or 5,600 miles. One dealer said the truck was unsafe to drive because the airbags might not deploy. Two crash reports describe airbags failing to deploy in collisions severe enough to total the truck. In one of those crashes, smoke filled the cabin and the driver was injured.
In owners' own words
Excerpts from complaints Sierra 1500 owners filed with NHTSA, as written. Listen for the same symptoms on your test drive.
Took the vehicle to the dealer because of an engine noise. It had issues with the valves knocking when it had around 1000 miles. I took it in and now the truck has around 67,000 miles and I’m being told it needs a new engine because of a bent rod in the engine. I was told that I need a new engine. Previously I had a lot of other issues with the front wheel hubs clicking. But, this truck didn’t even make it to 5 years and now it needs an engine.
Filed with NHTSA, November 2025
a lifter went out. While driving on a turnpike going 80 mph the engine starting knocking. The truck had to be towed to a GMC dealership where they confirmed a lifter went bad. the truck is a v8 with 8,000 miles on. the dealership advised what the problem was and replaced 4 of the 8 lifters. No warning was given, as soon as the lifter went out there were all sorts of errors that started showing up including emissions issues.
Filed with NHTSA, September 2021
Engine has stopped a couple of times at low speeds, Was able to restart and continue. Engine will occasionally make a "straining / Dieseling sputtering sound" when execellerating from low speeds or Stop. Transmission will make strange and strained shifts from time to time. This is reaccruing problem that comes and goes over the last approximately 2 yrs since about 9000 miles to current approx 25000 miles.
Filed with NHTSA, May 2025
Truck started to lose power or slip on quick acceleration on highway Truck would jolt or shudder. 63000 miles. Dealer diagnosed truck needs Torque converter and a valve body replacement. No warning lights Contacted GM. Have a case number, was told to take to dealer. It’s at dealer now, getting repaired. I’m wondering if GM has a bigger problem with transmission recall
Filed with NHTSA, March 2025
I took my truck through a car wash and then parked at my parents house. While the vehicle was parked, the trunk latch kept releasing. The trunk popped open. I left it open but you could hear the latch continually releasing and the lights blinking. This went on for an hour and I was unable to drive home because my trunk kept unlatching! A recall was released for other Sierras but not mine. Please investigate my vin and others that may be affected.
Filed with NHTSA, October 2025
Multi functional tail gate will open on its own while driving. I have had this repaired by gm 3 times and still have issues. This problem is currently on the recall list for 2500 hd series trucks and the 1500 series trucks in Canada but not on recall in united states. This problem poses a life threatening problem while on the road due to contents of truck possible becoming projectiles to other drivers due to tailgate opening on its own .
Filed with NHTSA, March 2025
I started my truck this morning, drove it 3 miles, and all of a sudden got an ESC warning, Parking break warning, and a degraded power steering warning all at one time. My steering wheel started vibrating vigorously, a clanking sound started under the hood somewhere, and none of my safety features worked after.. Cruise Control, Vehicle Collision Control, Vehicle Gap sensors, etc.. The vehicle is currently at the dealer being looked at.
Filed with NHTSA, October 2021
Alignment Cam Guide Pins sheared off while driving on highway. Alignment went all over the place and car was drifting side to side. Also, steering wheel spun a quarter turn while car was not turning but still driving on highway. Almost caused me to crash. GMC does not want to acknowledge the issue or allow me to file a warranty claim. Car could not be driven to GM dealership safely and had to be repaired at closest shop
Filed with NHTSA, March 2024
How the 2021 compares with other Sierra 1500 years
Complaints for this year next to the average for the other model years, area by area.
The 2021 ranks third for owner complaints among 8 Sierra 1500 years, about 1.3 times the average of the others. Newer years have had less time to collect complaints, so compare like with like.
- Engine178103
- Transmission9567
- Electrical4538
- Steering2517
- Brakes1118
- Body and structure819
Where the 2021 fits in the Sierra 1500's history
Redesigns and mid-cycle updates change what can go wrong.
The 2021 is the third model year of the Sierra 1500's fifth generation (2019 on).
Recalls to confirm (6)
Recall repairs are free at any GMC dealer, but the seller may never have had them done. Check each campaign number against the VIN.
25V274000EngineApr 2025
General Motors LLC (GM) is recalling certain 2021-2024 Cadillac Escalade and Escalade ESV, Chevrolet Silverado 1500, Suburban, and Tahoe, GMC Sierra 1500, Yukon, and Yukon XL vehicles equipped with a 6.2L V8 gas engine. The connecting rod and/or crankshaft engine components may have manufacturing defects that can lead to engine damage and engine failure.
Risk: Engine failure increases the risk of a crash.
Fix: Dealers will inspect the engine, and as necessary, repair or replace the engine. For vehicles that pass inspection, dealers will add higher viscosity oil, install 6 oil fill cap, replace the oil filter, and update the owner's manual. Repairs will be performed free of charge. Owner notification letters were mailed June 18, 2025. Owners may contact Cadillac customer service at 1-800-333-4223, Chevrolet customer service at 1-800-222-1020, or GMC customer service at 1-800-462-8782. GM's number for this recall is N252494000.
24V797000TransmissionOct 2024
General Motors, LLC (GM) is recalling certain 2020-2022 Chevrolet Silverado 1500, 2500, 3500, GMC Sierra 1500, 2500, 3500, 2021 Cadillac Escalade, Escalade ESV, Chevrolet Tahoe, Suburban, GMC Yukon, and Yukon XL vehicles equipped with diesel engines. The transmission control valve may fail and cause the rear wheels to lock-up.
Risk: Rear wheel lock-up can increase the risk of a crash.
Fix: Dealers will install new transmission control module software, free of charge. GM will provide a special coverage program to cover the repair of transmissions that are identified by the remedy software as containing a defective control valve. Owner notification letters were mailed December 12, 2024. Owners may contact GM customer service at 1-888-988-7267, Cadillac customer service at 1-800-458-8006, GMC customer service at GMC 1-800-462-8782 or Chevrolet customer service at 1-800-222-1020. GM's number for this recall is N242454440.
21V985000Wheels and tiresDec 2021
General Motors (GM) is recalling certain 2019-2021 GMC Sierra 1500 and Silverado 1500 vehicles equipped with certain accessory road tires and a 17" spare tire. The 17" spare tire provided with the vehicle is not compatible for use with the accessory wheels, which can cause the anti-lock brake system (ABS) to not function properly under certain conditions.
Risk: An ABS system that does not function properly can increase the risk of a crash.
Fix: Dealers will provide a new 17" spare tire and wheel assembly that is compatible with the accessory wheels, free of charge. Dealers will also apply a new spare tire information label, and provide owners with an owner's manual insert clarifying which spare tire to use with the accessory road tires and with the 17" original tires. Owner notification letters were mailed February 7, 2022. Owners may contact GM customer service at 1-800-462-8782 or GMC customer service at 1-800-462-8782. GM's number for this recall is N212346510.
20V811000Seat beltsDec 2020
General Motors, LLC (GM) is recalling certain 2020 Chevrolet Bolt EV and 2021 GMC Canyon and Sierra 1500, 2500 and 3500, Yukon, Yukon XL, Cadillac Escalade and Escalade ESV and Chevrolet Blazer, Camaro, Colorado, Equinox, Silverado 1500, 2500 and 3500, Suburban and Tahoe vehicles. Incorrect bolts may have been used at one or more fastening locations to secure the seat belts to the vehicle. If an incorrect bolt was used, the seat belt may not be properly attached to the vehicle.
Risk: If a seat belt assembly is not properly attached to the vehicle, the seat belt may not properly restrain an occupant in the event of a crash, increasing the risk of injury.
Fix: GM will notify owners, and dealers will replace the suspect bolts, free of charge. The recall began January 29, 2021. Owners may contact GMC customer service at 1-800-462-8785, Cadillac customer service at 1-800-458-8006, or Chevrolet customer service at 1-800-222-1020. GM's number for this recall is N202322230.
20V792000Seat beltsDec 2020
General Motors, LLC (GM) is recalling certain 2019-2021 Chevrolet Silverado 1500 and GMC Sierra 1500, 2021 Chevrolet Suburban and Tahoe and GMC Yukon XL and 2020-2021 Chevrolet Silverado 2500 and 3500 and GMC Sierra 2500 and 3500 vehicles. The seat belt brackets may not be secured to the seat frame in the front-row center seating position.
Risk: If a seat-belt bracket is not secured, the seat belt may not properly restrain an occupant in the front-row center seat position, increasing the risk of injury in a crash.
Fix: GM will notify owners, and dealers will inspect left-side and right-side front-row center seat-belt bracket attachments and reassemble it correctly as necessary, free of charge. The recall began January 26, 2021. Owners may contact GMC customer service at 1-800-462-8782, Chevrolet customer service at 1-800-222-1020. GM's number for this recall is N202314670.
20V684000Wheels and tiresNov 2020
General Motors LLC (GM) is recalling certain 2020 Buick Enclave, Cadillac XT5, GMC Acadia and Chevrolet Traverse vehicles and 2020-2021 Chevrolet Silverado 1500, GMC Sierra 1500 vehicles. The vehicles may have been manufactured with Continental tires that were overcured.
Risk: Overcured tires may experience a carcass break in the sidewall resulting in a sudden air loss or could develop a belt edge separation which could lead to partial or full tread/belt loss. Either condition increases the risk of a crash.
Fix: GM will notify owners, and dealers will inspect vehicles and replace tires that have DOT number and production mold number combinations identified by Continental, free of charge. The recall began December 17, 2020. Owners may contact GMC customer service at 1-888-988-7267, Buick customer service at 1-866-608-8080, Chevrolet customer service at 1-800-222-1020 or Cadillac customer service at 1-800-458-8006. GM's number for this recall is N202319030.
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