Most common 2021 Hyundai Sonata problems
Share of the 134 complaints; one complaint can involve more than one system. "~" is the median mileage when the problem started.
Hyundai Sonata complaints by model year
Best Sonata years: 2025, 2019, 2020. Years to avoid: 2011, 2013, 2012, 2015, 2017. Compare all years →
2021 Hyundai Sonata recalls (4)
Fuel system, gasoline
Hyundai Motor America (Hyundai) is recalling certain 2020-2023 Sonata vehicles. A damaged check valve can allow air to enter the fuel tank, causing it to expand and contact hot exhaust components, melting the tank.
Remedy: Dealers will inspect and replace the check valve. The fuel tank assembly will be inspected for damage and replaced if necessary. Additionally, dealers will inspect and update the engine control unit software.
Power train › Automatic transmission
Hyundai Motor Company (Hyundai) is recalling certain 2021-2022 Santa Fe, Sonata, Veloster N, 2022 Santa Cruz, Elantra N, and Kona N vehicles. The vehicle's "fail-safe" limited-mobility drive mode may be impaired, when prompted by a transmission oil pump malfunction, which can result in a complete loss of drive power.
Remedy: Dealers will inspect and replace the transmission, as necessary. Dealers will also update the transmission control unit software. All repairs will be performed free of charge.
Visibility › Windshield
Hyundai Motor America (Hyundai) is recalling certain 2020-2021 Santa Fe, 2021 Sonata, and Elantra vehicles. During manufacturing, the windshield may not have been properly bonded to the vehicle, allowing it to detach in a crash.
Remedy: Dealers will remove and reinstall the front windshield panel, free of charge. Owner notification letters were mailed June 20, 2022. Owners may contact Hyundai customer service at 1-855-371-9460.
Fuel system, gasoline › Delivery › Hoses, lines/piping, and fittings
Hyundai Motor America (Hyundai) is recalling certain 2021-2022 Santa Fe and Sonata vehicles equipped with 2.5L turbocharged engines. Fuel may leak at the pipe connection between the high-pressure fuel pump and fuel rail.
Remedy: Dealers will inspect and tighten, or replace the fuel pipe as necessary, free of charge. Owner notification letters were mailed on September 3, 2021. Owners may contact Hyundai customer service at 1-855-371-9460.
NHTSA defect investigations
Federal safety investigators have looked into a possible defect involving the 2021 Hyundai Sonata:
Loss of Motive Power
The National Highway Traffic Safety Administration (NHTSA) received a letter dated July 13, 2022, petitioning the Agency to initiate a safety defect investigation into loss of motive power allegations attributed to oil drain pan assembly failures on certain Hyundai Motor America, Inc. and Kia America, Inc. vehicles spanning Model Years (MY) 2005-2021.
What 2021 Hyundai Sonata owners say
Engine & cooling all 35 →
I purchased this vehicle brand new. It is still under factory warranty. It has approximately 14k miles on it. I have followed all recommended maintenance procedures. During a routine maintenance appointment at the dealership (Vancouver Hyundai 6802 NE 40th Street, Vancouver WA 98661) they identified a catastrophic engine failure due to internal component deterioration and the engine needs to be replaced. They have had my vehicle in their possession since [redacted] of this year for a total of 134 days. I have a case number at Hyundai # [redacted]. They have not been helpful in providing any information and as of now, I do not know when they even expect to receive a new engine.
The contact owns a 2021 Hyundai Sonata. The contact stated while driving 15 MPH, the contact noticed that the passenger's side rear seat level had become elevated. The contact stated that his daughter who was seated in the child seat head had started touching the top of the sunroof. The contact became aware of a gasoline odor coming from the engine. The contact also became aware that the vehicle was consuming an abnormal amount of gasoline. There was no warning light illuminated. The vehicle was taken to the dealer however, the diagnostic test result was undisclosed. The dealer was unsure of how to service the vehicle. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 87,000. The VIN was not included.
Fuel & propulsion system all 34 →
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 gas station, and while attempting to refuel the vehicle, the fuel did not go into the tank. The vehicle was towed to the residence. The vehicle was later towed to the dealer, where it was diagnosed with a failed fuel system and a failed fuel tank. The contact was informed that the fuel system and fuel tank needed to be replaced. The vehicle was not repaired. The contact was informed that the failure was associated with the unrepaired recall. The contact was informed that the vehicle was a fire risk. …
The contact owns a 2021 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. The vehicle was driven to the shoulder of the road. The contact stated that the fuel level indicated empty, and the low fuel warning light was illuminated. The passenger seated in the rear seat noticed that the rear seat was out of place and that the seat was very hot. The vehicle was refueled prior to the failure. The contact and the other occupants in the vehicle exited the vehicle. The vehicle was towed to the residence. The dealer was made aware of the failure. The contact was informed that the failure was like the failure listed in NHTSA Campaign Number: 25V796000 (Fuel System, Gasoline). The contact was unaware of the open recall because a recall notification was not received. …
Transmission & drivetrain all 25 →
The contact owns a 2021 Hyundai Sonata. The contact received notification of the NHTSA Campaign Number: 22V746000 (Power Train) however, the contact stated that on numerous occasions while driving at various speeds, the accelerator pedal was depressed however, the vehicle decelerated and went into "fail-safe" mode. The vehicle was taken to the dealer where it was diagnosed that the transmission control unit software needed be updated. The vehicle was repaired; however, the failure recurred. Additionally, the contact stated that prior to the recall repair, while driving at an undisclosed speed, the vehicle failed to accelerate as needed. The vehicle was taken to the dealer and the transmission was replaced. The vehicle was not repaired. …
The contact owns a 2021 Hyundai Sonata. The contact became aware that the VIN was included in NHTSA Campaign Number: 22V746000 (Power Train); however, parts to do the recall repair were not yet available. The local dealer was contacted. The contact stated that the vehicle would delay while starting. The vehicle was taken to the dealer where it was diagnosed but no issues were found. The vehicle was not repaired. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue and informed the contact that a recall notification would be mailed to him in December. The failure mileage was approximately 15,000. VIN tool confirms parts not available.
2021 Hyundai Sonata engines & fuel economy
| Engine | Transmission | Drive | MPG city / hwy / combined |
|---|---|---|---|
| 2.0L 4-cyl hybrid | 6-speed dual-clutch | FWD | 50 / 54 / 52 |
| 2.5L 4-cyl | 8-speed automatic | FWD | 28 / 38 / 32 |
| 1.6L 4-cyl turbo | 8-speed automatic | FWD | 27 / 37 / 30 |
| 2.5L 4-cyl turbo | 8-speed dual-clutch | FWD | 23 / 33 / 27 |
EPA ratings. Class: Large car.
Frequently asked questions
Is the 2021 Hyundai Sonata a good car?
Based on 134 owner complaints filed with NHTSA, the 2021 Sonata rates average: 18% fewer complaints than a typical year of the Sonata at the same age. Complaint counts don't account for sales volume or individual maintenance, so have any used car inspected before buying.
What is the most common problem with the 2021 Hyundai Sonata?
The engine & cooling — 35 complaints, 26% of all complaints for this model year. Next are the fuel & propulsion system (34) and transmission & drivetrain (25).
How many recalls does the 2021 Hyundai Sonata have?
There are 4 recalls for the 2021 Hyundai Sonata, the most recent from November 17, 2025 (fuel system, gasoline). Recall repairs are free at any authorized dealer — check whether yours has been done with the VIN recall check.
What are the best and worst years of the Hyundai Sonata?
The best years by complaints, compared at the same age, are 2025, 2019 and 2020. Years to avoid or approach with caution: 2011, 2013, 2012, 2015 and 2017. See the full Hyundai Sonata years comparison.
At what mileage do 2021 Hyundai Sonata problems happen?
The median mileage reported in complaints is about 41,000 miles; 64% of problems with a recorded mileage started before 50,000 miles.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.