The Lemon Index2021 Hyundai Sonata.
The 2021 Hyundai Sonata is worse than average by owner complaints: 103 complaints in its first 3 years and a Lemon Index of 128, where 100 is the average car. Owners complain most about engine, it has 4 recalls, and it gets 27 to 52 mpg combined. The best Hyundai Sonata year is 2004.
Before you buy. What matters most for this car.
How serious. Out of 189 owner complaints, owners reported:
Every Hyundai Sonata year. 2021 is highlighted. Lower is better.
What owners complain about most. From owner complaints to the government.
Share of this year's owner complaints filed with NHTSA, not the share of cars that break. One complaint can name more than one area.
When owners reported problems. From owner complaints to the government.
Most owners who filed a complaint with NHTSA had 15K to 70K miles on the car (27 complaints listed the miles). This shows when people who had a problem reported it, not the odds that your car will have it.
Recalls 4
- fuel system, gasoline 2025
A damaged check valve can allow air to enter the fuel tank, causing it to expand and contact hot exhaust components, melting the tank.
- transmission & drivetrain 2022
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.
- visibility 2021
During manufacturing, the windshield may not have been properly bonded to the vehicle, allowing it to detach in a crash.
Show all 4 recalls
- fuel system, gasoline 2021
Fuel may leak at the pipe connection between the high-pressure fuel pump and fuel rail.
Recall repairs are free at any dealer. A recall only matters if it's still open on that exact car, so check its VIN.
Problems Hyundai told dealers about
Hyundai sent dealers 111 repair notes for this car. The ones about its biggest problems:
- If you are servicing an applicable vehicle with a Check Engine light on and one or more of the…
- If you are servicing an 8-speed front-wheel-drive vehicle with the DTC or symptoms listed…
- Check engine light in conjunction
Ask a seller or mechanic if these were done. Some are free under warranty or a special program.
Government investigations
- ClosedPedestrian alert sounds2023
- ClosedLoss of motive power2022–2023
NHTSA looks into a problem when enough owners report it. Many end in a recall.
Safety
Crash test details
| Version | Overall | Front | Side | Rollover |
|---|---|---|---|---|
| Hyundai Sonata 4 DR FWD | ★★★★★ | ★★★★☆ | ★★★★★ | ★★★★★ |
| Hyundai Sonata Hybrid 4 DR FWD | ★★★★★ | ★★★★☆ | ★★★★★ | ★★★★★ |
Fuel cost and engines
About $1250–2400 a year in fuel (EPA estimate). Engines: 1.6L 4-cyl, 2.0L 4-cyl, 2.5L 4-cyl.
In owners' words
the coolant reservoir has been dropping showing levels below min even after topping it off
2021 Hyundai Sonata owner · NHTSA complaint 11556589
More owner reports
Integrated 12v battery in hybrid system keep draining out. I have to manually open the car and reset it every time in order to be able to drive.
NHTSA complaint 11589918
Coolant leak acting like blown head gasket. Coolant was leaking into the exhaust system. Defective EHRS system
NHTSA complaint 11609725
Quick answers
Is the 2021 Hyundai Sonata reliable?
No, it is worse than average by government complaints. It drew 1.3× the average car's complaints filed with NHTSA in its first 3 years, per car sold (Lemon Index 128; 100 is average, lower is better). The best Hyundai Sonata year by this measure since 2010 is 2010.
What are the most common 2021 Hyundai Sonata problems?
In owner complaints to the government, the parts named most are engine (31%), electrical (27%) and transmission & drivetrain (15%). That is the share of complaints, not the share of cars that break.
How many recalls does the 2021 Hyundai Sonata have?
4 safety recalls (latest: fuel system, gasoline). Recall repairs are free at any dealer; check a specific car's VIN at nhtsa.gov/recalls.
What gas mileage does the 2021 Hyundai Sonata get?
27 to 52 mpg combined, depending on the engine (EPA estimate).
Is the 2021 Hyundai Sonata safe?
NHTSA gave it 5 out of 5 stars overall in its best tested version. Ratings differ by body style, and the full table is on the advanced page.
At what mileage do 2021 Hyundai Sonata problems start?
Half of the owners who gave a mileage reported the problem between 15,000 and 70,000 miles. The middle report was at 35,000 miles, from 27 complaints.
Does the 2021 Hyundai Sonata have transmission problems?
Transmission and drivetrain issues make up 15% of its owner complaints.
How much does the 2021 Hyundai Sonata cost in fuel a year?
About $1250 to $2400 a year, by the EPA's current estimate.
What engines does the 2021 Hyundai Sonata have?
1.6L 4-cyl, 2.0L 4-cyl, 2.5L 4-cyl.
What Hyundai Sonata year is better than the 2021?
By owner complaints per car sold, the best recent years are 2010, 2019 and 2014.
Lemon Index = safety complaints filed with the U.S. government (NHTSA) in a car's first 3 years, per car sold, against the average car of the same model year. 100 is average; lower is better. A complaint is an owner's report, not a confirmed defect. How it works