2021 Hyundai Sonata fuel/propulsion system problems
20 owner complaints filed with NHTSA name the fuel/propulsion system on the 2021 Hyundai Sonata — 15% of all complaints for this model year.
What owners report
“I took my vehicle in for the safety recall due to an expanding fuel tank on 08/03/2026. I received my vehicle back on 8/12/2026. Hyundai performed an improper repair on the vehicle that will not correct the fuel tank expansion. They replaced the same check valve that was replaced last time I…”
filed Aug 16, 2026
“Gas tank expansion and pcv melted. Car smells like gas when I was driving earlier, and my garage was flooded with the fumes of gasoline.”
filed Aug 7, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Related service bulletins
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
Fuel/propulsion System problems in other Sonata years
| Year | Reports | Share |
|---|---|---|
| 2024 Sonata | 1 | 2% |
| 2023 Sonata | 37 | 43% |
| 2022 Sonata | 22 | 24% |
| 2020 Sonata | 45 | 25% |
| 2019 Sonata | 12 | 7% |
| 2018 Sonata | 31 | 8% |
| 2017 Sonata | 33 | 4% |
| 2016 Sonata | 33 | 5% |
| 2015 Sonata | 75 | 7% |
| 2014 Sonata | 49 | 7% |
| 2013 Sonata | 134 | 7% |
| 2012 Sonata | 99 | 6% |
Other reported problem areas on the 2021 Hyundai Sonata
Counts are unique NHTSA complaints naming this component group. Complaints are unverified owner reports; mileage is computed only from complaints that included a usable odometer reading.