2016 Hyundai Sonata engine problems
450 owner complaints filed with NHTSA name the engine on the 2016 Hyundai Sonata — 62% of all complaints for this model year.
What owners report
“I am concerned that the engine may seize or stall without warning while driving, creating a risk of crash, injury, or death. The Theta II engine defect is known to cause engine seizure, stalling, and fire. Hyundai has denied warranty coverage based on mileage and second-owner status — both of which…”
filed Sep 15, 2026
“The vehicle experienced a Theta II engine failure at under 57,830 miles while driving on northbound [XXX] near the [XXX] Parkway U-turn in [XXX]. The engine made a loud noise and lost power. I was able to coast to the far right side of the U-turn under the bridge. I called HERO (Austin's emergency…”
filed Sep 15, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Related service bulletins
Certain Santa Fe (TMA), Santa Fe Sport (AN), Sonata (LFA), and Tucson (TL) vehicles equipped with Theta II engines may exhibit elevated engine-out emissions. The California Air Resources Board has determined that these…
26-01-013H-2 DN · Service Campaign · issued May 21, 2026Certain Santa Fe (TMA), Santa Fe Sport (AN), Sonata (LFA), and Tucson (TL) vehicles equipped with Theta II engines may exhibit elevated engine-out emissions. This bulletin provides instructions for updating the Engine…
26-01-013H-2 TSB · Service Campaign · issued May 21, 2026Following completion of Service Campaign 9C2 (Theta II Emissions Improvement), certain vehicles may exhibit a brief hesitation or rough shifting condition during cold start operation. If present, this condition is…
9C2 060518 · Service Campaign · issued May 19, 2026Following completion of Service Campaign 9C2 (Theta II Emissions Improvement), certain vehicles may exhibit a brief hesitation or rough shifting condition during cold start operation. If present, this condition is…
9C2 DCS 260518 · Service Campaign · issued May 19, 2026Certain 2019 – 2020 model year Santa Fe, 2017 – 2018 model year Santa Fe Sport, 2015 – 2019 model year Sonata, and 2018 – 2021 model year Tucson vehicles may exhibit elevated engine-out emissions. Hyundai is conducting…
9C2 OL · Service Campaign · issued Apr 14, 2026
Engine problems in other Sonata years
| Year | Reports | Share |
|---|---|---|
| 2024 Sonata | 3 | 7% |
| 2023 Sonata | 27 | 31% |
| 2022 Sonata | 25 | 27% |
| 2021 Sonata | 34 | 26% |
| 2020 Sonata | 31 | 17% |
| 2019 Sonata | 86 | 53% |
| 2018 Sonata | 210 | 56% |
| 2017 Sonata | 383 | 50% |
| 2015 Sonata | 623 | 54% |
| 2014 Sonata | 301 | 40% |
| 2013 Sonata | 735 | 39% |
| 2012 Sonata | 567 | 36% |
Other reported problem areas on the 2016 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.