2021 GMC Sierra 1500 problems & reliability
528 owner complaints filed with NHTSA for the 2021 GMC Sierra 1500, alongside 7 safety recall campaigns. Last verified Aug 7, 2026. Complaints are unverified reports submitted by owners to the federal Office of Defects Investigation.
Each complaint is counted once (by NHTSA case number), even when it names several vehicles.
2 complaints report injuries (2 injured).
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Engine | 275 | 52% |
| Power Train | 129 | 24% |
| Electrical System | 71 | 13% |
| Engine and Engine Cooling | 46 | 9% |
| Unknown OR Other | 40 | 8% |
| Fuel/propulsion System | 33 | 6% |
| Steering | 32 | 6% |
| Service Brakes | 22 | 4% |
| Structure | 11 | 2% |
| Latches/locks/linkages | 9 | 2% |
Component groups as classified by NHTSA. A complaint can name more than one component, so shares may sum to more than 100%.
Common symptoms owners describe
Keyword analysis of complaint narratives; one complaint can describe several symptoms.
Mileage when problems occurred
Half of the failures with a reported odometer reading occurred by 50,000 miles (middle 50% between 21,404 and 80,000 miles), based on 108 complaints that included mileage.
Complaints by incident year
What owners report
“P1010 and P2B86 engine code, constant cooling fan on engine. Confirmed by dealership, quoted for coolant control valve. VIN not included in special coverage N252508341 for this known issue. Limited engine power alert, unable to maintain speed on highway. Dangerous condition traveling under speed limit.”
Engine · filed Jul 31, 2026
“Engine temp rises way above mid-level and will stay there for several minutes before cooling back down to normal temps. 2 different mechanic shops have told me it's the coolant control valve, but want $2500 to fix it. This service bulletin is for the same year, make, model, and motor as my truck, but the dealership…”
Engine · filed Jul 31, 2026
“2021 Harley Davidson Sierra 4WD, 6.2L L87. Started the truck in the morning and immediately heard intermittent, very loud banging noise coming from engine. Shut truck down quickly and had it towed to dealer. Diagnosis was bent pushrods & failed lifters which were replaced under warranty. Factory warranty expired only…”
Engine · filed Jul 30, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Federal defect investigations
- Loss of motive power due to engine failure post recall remedy
Recall Query RQ26001 · opened Jan 16, 2026 · open
- Loss of motive power due to engine failure
Engineering Analysis EA25007 · opened Oct 23, 2025 · open
- Loss of motive power due to engine failure
Preliminary Evaluation PE25001 · opened Jan 16, 2025 · closed Oct 23, 2025 · led to recall 25V274
- Air Bag Malfunction
Preliminary Evaluation PE21010 · opened Apr 9, 2021 · closed Aug 24, 2023
Technical service bulletins
1,446 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2021 GMC Sierra 1500. The 10 most recent:
This document assists GM dealer technicians with diagnosing torque converter concerns to ensure torque converter replacement is necessary. The torque converter part number will be placed on order restriction, and the…
PIP6127 · Service Bulletin/Repair Instructions · issued Jul 31, 2026
This PI provides information to repair the door water deflector which is not sealed properly allows water into the door jam/sill area.
PIT5680B · Service Bulletin/Repair Instructions · issued Jul 23, 2026
PI to help diagnose A/C concern
PIT5099J · Service Bulletin/Repair Instructions · issued Jul 21, 2026
This PI provides diagnostic tips for diagnosing electric trailer brakes issues.
PIT5509N · Service Bulletin/Repair Instructions · issued Jul 21, 2026
This PI was created to help avoid unnecessary front camera module replacements
PIT6473F · Service Bulletin/Repair Instructions · issued Jul 17, 2026
This PI provides a diagnostic tip on poor a/c performance due to a condenser issue and instructions to replace the ac condenser.
PIT5767B · Service Bulletin/Repair Instructions · issued Jul 13, 2026
The purpose of this PI is to inform dealer technicians of a normal cab pressure relief valve noise to avoid unnecessary part replacement
PIT6532 · Service Bulletin/Repair Instructions · issued Jul 6, 2026
This Preliminary information communicates an issue with an OTA pending message still displayed after an OTA event and how to reset/clear the message.
PIT5966F · Service Bulletin/Repair Instructions · issued Jun 23, 2026
This PI provides diagnostic steps for dealer technicians to verify the condition and ensure that part replacement is necessary
PIT6523 · Service Bulletin/Repair Instructions · issued Jun 10, 2026
This Preliminary information communicates an issues with the HVAC making a hum buzz noise when the blower is set to a higher speed. Engineering is working on a new HVAC door seal material to correct the noise.
PIT6132E · Service Bulletin/Repair Instructions · issued Jun 9, 2026
TSBs are repair guidance manufacturers send to dealers — they are not recalls and repairs are not automatically free. Full documents are available on NHTSA’s site.
Safety recalls
The 2021 GMC Sierra 1500 has 7 NHTSA recall campaigns — recall repairs are free at franchised dealers regardless of the vehicle’s age.
Check whether your specific vehicle is affected
Recall campaigns often cover only certain VIN ranges. Enter your VIN on the official NHTSA site to confirm whether your vehicle is included and whether the repair is still open.
Check VIN on NHTSA →Buying a used 2021 GMC Sierra 1500?
- · Decode the seller’s VIN with our free VIN decoder to confirm the exact year, engine and trim.
- · Check for unrepaired recalls by VIN on NHTSA’s official lookup — recall repairs are free.
- · Owners most often reported problems around 50,000 miles — budget accordingly if the car is approaching that mileage.