2021 Gmc Sierra: Is It Reliable?
Problems, Recalls & Buyer Verdict
Used GMC SIERRA shoppers should review this model-year complaint and recall record before making an offer. Current data includes 500 complaints, with Engine Problems as the top reported area.
2021 Gmc Sierra Fuel Economy
β EPA Official DataEPA-rated fuel economy across 8 2021 Gmc Sierra trim configurations. The median figure is shown; range reflects all available trims.
Source: EPA FuelEconomy.gov. Figures reflect EPA lab testing; real-world results vary by driving style, load, and conditions. 8 trims analysed.
Based on NHTSA complaint data, the 2021 Gmc Sierra has 500 owner complaints, 9 crash-related complaints, and 10 recall campaigns on record. The most frequently reported component is Engine Problems. NHTSA reliability signal: Notable Issues.
- Make
- Gmc
- Model
- Sierra
- Model year
- 2021
- NHTSA owner complaints
- 500
- Crash-related complaints
- 9
- Safety recall campaigns
- 10
- Top reported component
- Engine Problems
- Reliability signal
- Notable Issues
- EPA MPG combined
- 19
- EPA MPG city / highway
- 17 / 23
- Fuel type
- Regular Gasoline
Most Common 2021 Gmc Sierra Problems
Top owner-reported complaint areas and where they often appear.
Engine Problems
Transmission / Drivetrain
Electrical Faults
Complaint patterns center on Engine Problems, Transmission / Drivetrain, Electrical Faults. Use these as a pre-purchase inspection guide, then verify recall and damage history on the specific VIN.
Should You Buy a Used 2021 Gmc Sierra?
This GMC SIERRA year shows a meaningful number of reported issues, so buyers should only proceed after a careful records review and inspection.
Model-year complaint trends can reveal recurring trouble spots before you spend money on inspections, financing, or repairs.
May Suit
This year may suit buyers who prioritize complete maintenance records and pass a pre-purchase inspection.
May Want to Avoid
Buyers who want a lower-risk ownership profile may prefer comparing nearby model years before committing.
What to Check Before Buying a Used 2021 Gmc Sierra
Inspection Focus
- Inspect the most frequently reported complaint components on this model year
- Confirm recall repairs were completed and documented
- Check for accident damage, title brands, and mileage inconsistencies on the exact VIN
Before You Close the Deal
- Run a VIN check on the specific vehicle you are considering
- Verify all open recalls are completed at nhtsa.gov/recalls
- Request service records for the most-reported complaint components
- Have a certified mechanic inspect the vehicle before purchase
Shortlist with model-year data. Decide with the exact VIN.
Before buying a used 2021 Gmc Sierra, run a VIN history report to verify accidents, title brands, odometer records, theft checks, and open recalls for the exact vehicle.
What the Complaint Data Suggests
Editorial interpretation of NHTSA public complaint data. Source: nhtsa.gov. Complaints are owner-submitted and do not confirm a defect. Methodology
The GMC SIERRA has 500 NHTSA complaints and 10 recalls on record. 9 complaints involve crash-related incidents. This data reflects owner-reported issues submitted to the National Highway Traffic Safety Administration.
Recall context: 10 recall campaigns are on record, so recall completion status should be confirmed on the exact VIN before purchase.
- 500 total complaints filed with NHTSA
- 10 federal recall campaigns
- 9 crash-related complaints on record
- Review NHTSA complaint history for the most-reported components
- Check recall completion status at nhtsa.gov/recalls
- Verify service records for frequently complained components
All 2021 Gmc Sierra Complaints by Category
Every owner-reported complaint category filed with NHTSA for the 2021 Gmc Sierra. Use this as a pre-purchase inspection checklist.
| Component | Complaints | Crashes | Fires | Avg Mileage | Volume |
|---|---|---|---|---|---|
| Engine Problems | 277 | β | 3 | β | |
| Transmission / Drivetrain | 126 | 1 | β | β | |
| Electrical Faults | 63 | 1 | 2 | β | |
| Uncategorized Issues | 41 | 2 | 2 | β | |
| Brake System | 25 | 1 | 1 | β | |
| Fuel/Propulsion System | 24 | β | 1 | β | |
| Steering Defects | 21 | 1 | β | β | |
| Structural Problems | 13 | 1 | 1 | β | |
| Door Lock Issues | 13 | β | β | β | |
| Headlight/Taillight Failures | 10 | β | β | β | |
| Forward Collision Avoidance: AEB | 7 | 1 | β | β | |
| Lane Departure | 7 | β | β | β | |
| Suspension Failures | 6 | β | β | β | |
| Tire Issues | 5 | β | β | β | |
| Wheel Issues | 5 | 2 | β | β | |
| Unintended Acceleration | 5 | β | β | β | |
| Visibility/Wiper | 5 | β | β | β | |
| Airbag Malfunctions | 5 | 3 | 1 | β | |
| Back Over Prevention | 4 | β | β | β | |
| Seat Belt Issues | 3 | β | β | β | |
| Fuel System | 2 | β | β | β | |
| Hydraulic | 1 | β | β | β | |
| Gasoline | 1 | β | β | β | |
| Visibility | 1 | β | β | β | |
| Parking-Brake Issues | 1 | β | β | β | |
| Diesel | 1 | β | β | β |
Source: NHTSA Complaints Database. Complaint counts may exceed total complaints because one report can span multiple categories.
Real Owner Complaints
Read what owners actually reported to NHTSA for the 2021 Gmc Sierra. Type a keyword (e.g. βtransmissionβ, βstallingβ, βbrakesβ) to filter.
2021 GMC Sierra AT4, VIN [XXX] , NHTSA Campaign 25V-274, GM Case XXX. Brake pad monitor failed at 128,923 miles -- 24 miles after leaving Penske Chevrolet (released at 128,899, RO XXX, 04/17/2026). Brakes became spongy immediately following service. Monitor disabled entirely to sβ¦
Coolant Control Valve
Right after i bought the car I had a very bad misfire on cylinder 1, the car would shake at idle. Took to dealership and they said they replaced all the spark plugs and replaced cylinder 1 coil. about a week later the misfire and shaking started again but this time it would come β¦
Engine has a terrible shake, and I was informed by a mechanic that it has a misfire and no compression in piston number seven
I have the same model and year for GMC as bulletin 25NA-185, Engine Coolant Control Valve Failures on 3.0L Duramax (Dec 4, 2025), and am experiencing the same exact issue. Apparently my VIN is not included and I can't get an answer from GMC or the local dealer why it's not coveβ¦
Coolant control valve not working correctly exhaust fan on high all the time but is never overheating this has been going on for a week it shows there is a 150000 mile warranty on it but not for mine
Coolant control valve has failed and caused the check engine light to occur is available for inspection. Could cause the car to overheat and cause harm to myself or others Yes has been confirmed by dealer No GM has a special coverage out for the specific vehicle and model years fβ¦
The contact owns a 2021 GMC Sierra LD Crew. The contact stated that while driving on the highway at an undisclosed speed, the vehicle's bedrail attachment fully detached from the vehicle. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure.β¦
Engine coolant control valve needed to be replaced. Special coverage (N252508341) was issued out by GM to fix this problem on 2021 GMC Sierra 1500 vehicles.
Driving normal traffic . Started hearing ticking . Check engine light flashing ,service esc and braking system light up. Parking not loud ticking from engine bay
Driving down road and had total loss of power steering and yes it is available for inspection. Almost drove it off the road due to loss of steering Yes, it happened to be a failed main grounding strap that created the issue. The dealership made the repair. No, it was inspectedβ¦
The contact owns a 2021 GMC Sierra 2500. The contact stated that on several occasions, the automatic power side-out step failed to extend as designed. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure. The failure mileage was 93,726.
The contact owns a 2021 GMC Sierra 1500. The contact stated that while her son was driving 55 MPH and depressing the brake pedal, the vehicle failed to slow down as intended. The driver attempted to use the parking brake to slow the vehicle, but the vehicle failed to slow down. Tβ¦
XXX Power Assist Step Reversing I have a 2021 GMC Sierra 2500HD that the local dealership (Ozark MO 65714) is stating has expired and not covered by the warranty. I researched online and as I understand this recall falls under SAFTEY recalls and is to be fixed and doesn't expirβ¦
Driving and lost all power to truck annd lost control. Was able to coast truck with no accidents. all lights turned on dash board. Engine stating to make horrible noise. Cylinder 1 had a collapsed lifter which cause the failure. They replaced all lifters on the left side. Tβ¦
Engine coolant control valve
Coolant control valve failing. Warranty not covering this part. Seems to be a manufactured issue. Happening on a lot of 2021 GMNC Sierras with the 3.0l Duramax.
My L87 engine has failed due to a manufacturing issue. The recall number for this issue is N252494000. Upon contacting GMC, they state that my VIN number is not included in this recall despite having the same exact issues. I took the vehicle into a mechanic as soon as a problem hβ¦
While driving into work, I noticed a knocking sound from the outside of the vehicle. Once parked, upon further inspection I narrowed down the area of the noise to the bottom rear of the engine/front of transmission. Fortunately, I was able to park in front of my office building aβ¦
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving approximately 45 MPH, the transmission inadvertently shifted from drive (D) to first gear. The check engine warning light was illuminated. The vehicle was pulled over to the side of the road and then tβ¦
Source: NHTSA Complaints Database. Real owner reports for the 2021 Gmc Sierra.
2021 Gmc Sierra Recalls
10 campaignsNHTSA recall campaigns for the 2021 Gmc Sierra. 10 recall campaigns are on record, so recall completion status should be confirmed on the exact VIN before purchase. Recalls are free to fix at authorized dealers, but completion status must be verified on the exact VIN.
2021 Gmc Sierra Buying FAQ
Buyer-focused answers based on real NHTSA complaint and recall data for this model year.
Is the 2021 Gmc Sierra reliable?βΎ
Notable Issues. NHTSA currently shows 500 owner complaints, 9 crash-related complaints, and 10 recall campaigns for this model year. This GMC SIERRA year shows a meaningful number of reported issues, so buyers should only proceed after a careful records review and inspection. Treat this as a model-year signal, then verify the exact vehicle's condition and history before purchase.
What are the most common problems with the 2021 Gmc Sierra?βΎ
#1: Engine Problems (277 complaints). #2: Transmission / Drivetrain (126 complaints). #3: Electrical Faults (63 complaints)
At what mileage do problems start on the 2021 Gmc Sierra?βΎ
Mileage data is not available or insufficient for this model year.
How safe is the 2021 Gmc Sierra?βΎ
Complaint data is not the same as crash-test scoring, but it does highlight possible risk patterns. For the 2021 Gmc Sierra, NHTSA complaints include 9 crash-related reports and 5 fire reports out of 500 total complaints. 2 injury reports are also on file. For controlled crash-test ratings, check nhtsa.gov/ratings.
Does the 2021 Gmc Sierra have any recalls?βΎ
Yes. 10 NHTSA recall campaigns affect the 2021 Gmc Sierra. A major recall area is TIRES:TEMPORARY/EMERGENCY SPARE TIRE. 10 recall campaigns are on record, so recall completion status should be confirmed on the exact VIN before purchase. Always verify open recalls by VIN because completion status varies by vehicle.
Should I buy a 2021 Gmc Sierra?βΎ
This GMC SIERRA year shows a meaningful number of reported issues, so buyers should only proceed after a careful records review and inspection. Model-year complaint trends can reveal recurring trouble spots before you spend money on inspections, financing, or repairs. Pay extra attention to Engine Problems during inspection. Before committing, run a VIN history report to verify accidents, title brands, odometer records, and recall completion for the exact car.
Source: NHTSA (National Highway Traffic Safety Administration) complaint and recall databases, aggregated by VinSpector AI.
Wider context: See the full Gmc Sierra reliability report with year-by-year comparison.
Owner Reliability Rating
Rate the 2021 Gmc Sierra based on your ownership experience.
Add your rating:
Ratings are based on owner experience and are separate from NHTSA data shown above.
Check the Exact Vehicle History Before You Buy
Model-year complaints and recalls reveal patterns. A VIN report confirms whether the exact car has accident history, title brands, mileage issues, or open recalls.