2021 Hyundai Sonata problems & reliability
125 owner complaints filed with NHTSA for the 2021 Hyundai Sonata, alongside 4 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 (12 injured).
Federal crash records (FARS 2020–2023): 2021 Hyundai Sonata vehicles were involved in 54 fatal crashes with 36 occupant deaths. Involvement counts are not adjusted for how many are on the road and do not imply fault or a vehicle defect.
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Engine → | 34 | 27% |
| Unknown OR Other | 31 | 25% |
| Power Train → | 22 | 18% |
| Fuel/propulsion System → | 18 | 14% |
| Electrical System → | 16 | 13% |
| Fuel System, Gasoline → | 11 | 9% |
| Forward Collision Avoidance | 8 | 6% |
| Visibility/wiper | 8 | 6% |
| Air Bags | 4 | 3% |
| Structure | 4 | 3% |
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 35,000 miles (middle 50% between 14,150 and 60,100 miles), based on 23 complaints that included mileage.
Complaints by incident year
What owners report
“The contact owns a 2021 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the fuel gauge indicated that the tank was half full. The contact stated that the gauge erroneously indicated that the tank was empty, and the check engine warning light was illuminated. The vehicle was driven to the…”
Fuel System, Gasoline · filed Aug 4, 2026
“Going down the road driving the car lost power and went in limp mode with no warnings on the dash at all!”
Power Train · filed Aug 1, 2026
“1. Component Failed: Panoramic Sunroof Glass Assembly (Structure / Visibility / Glass). Details: While traveling at highway speed on the freeway, the panoramic sunroof glass spontaneously exploded outward without warning or impact from any foreign object. Inspection: I have not had the vehicle repaired yet so it is…”
Unknown OR Other · filed Jul 28, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Federal defect investigations
- Loss of Motive Power
Defect Petition DP22003 · opened Sep 12, 2022 · closed Dec 12, 2023
Technical service bulletins
88 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2021 Hyundai Sonata. The 10 most recent:
This bulletin provides information related to a Transmission Control Unit (TCU) software update for some vehicles equipped with an 8-speed wet dual clutch transmission (8WDCT). The software update revises the touch…
26-AT-005H TSB · Service Bulletin/Repair Instructions · issued Jun 5, 2026
Some vehicles may exhibit difficulty starting in cold weather. This bulletin provides the procedure to perform an inspection on the starter magnetic switch for potential freezing and, if necessary, replace the starter…
26-EE-003H TSB · Service Bulletin/Repair Instructions · issued Apr 18, 2026
The National Highway Traffic Safety Administration (NHTSA) has identified the presence of substandard and dangerous driver’s-side airbag inflators manufactured by Jilin Province Detiannuo Automobile Safety System Co.…
DTN DL · Other · issued Apr 10, 2026
The National Highway Traffic Safety Administration (NHTSA) has issued an urgent safety advisory regarding dangerous, counterfeit driver‑side airbag inflators manufactured by Jilin Province Detiannuo Automobile Safety…
DTN DCS · Other · issued Apr 10, 2026
Some Santa Cruz (NXT), Santa Fe (TMA, MX5A), and Sonata (DN8A) models may require replacement of the 8-speed wet dual clutch transmission (8WDCT) when the vehicle sets one of the high pressure electric oil pump (HP EOP)…
26-AT-001H TSB · Service Bulletin/Repair Instructions · issued Mar 3, 2026
Some 2019MY and newer vehicles equipped with a front view camera may illuminate certain warning lights and trigger DTC C272246 fault code for the front camera. In the following cases, the front camera auto-calibration…
26-AD-001H TSB · Service Bulletin/Repair Instructions · issued Feb 25, 2026
Some Sonata (DN8, DN8A) vehicles may have DTCs P218100, P2181F0, and/or P2181F1 (Cooling System Performance) set in the Engine Control Module, resulting in an illuminated Check Engine warning lamp. Follow the procedure…
26-EM-003H TSB · Service Bulletin/Repair Instructions · issued Feb 5, 2026
Some vehicles equipped with a 2.5L GDI Theta III engine (non-Turbo) may exhibit one or more misfire DTCs due to the GDI fuel injectors leaking internally. This may be caused by internal filter breakage in the injector…
26-FL-001H TSB · Service Bulletin/Repair Instructions · issued Jan 7, 2026
This bulletin provides information regarding condensation related to the accumulated moisture in the headlamp, rear combination lamp, daytime running lamp (DRL), or fog lamp. This TSB illustrates the various causes of…
25-BD-012H TSB · Service Bulletin/Repair Instructions · issued Nov 6, 2025
This bulletin provides information related to the changes introduced in the 2025 1st Navigation Map and Software Update. The changes may vary depending on vehicle type, model, and navigation system as described in this…
25-BE-020H TSB · Service Bulletin/Repair Instructions · issued Sep 30, 2025
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 Hyundai Sonata has 4 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 Hyundai Sonata?
- · 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 35,000 miles — budget accordingly if the car is approaching that mileage.