2021 Hyundai Sonata engine problems
34 owner complaints filed with NHTSA name the engine on the 2021 Hyundai Sonata — 26% of all complaints for this model year.
What owners report
“At approximately 130,000 miles, vehicle developed and internal coolant leak caused by a failed Exhaust Heat Recovery System (EHRS) in the center muffler assembly, matching TSB 23-EM-009H - a known manufacturing defect documented by Hyundai. Coolant has been slowly leaking internally into the…”
filed Jun 24, 2026
“The car will idle high around 1200 rpms. The car will most of the times fix the issue when you turn the car off and back on but it will start again after driving. This is a known issue with the car. I have had the egr valve replaced since it will pop up the codes P240F and P049 for egr slow…”
filed Jun 1, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Related service bulletins
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, 2026Some 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
Engine problems in other Sonata years
| Year | Reports | Share |
|---|---|---|
| 2024 Sonata | 3 | 7% |
| 2023 Sonata | 27 | 31% |
| 2022 Sonata | 25 | 27% |
| 2020 Sonata | 31 | 17% |
| 2019 Sonata | 86 | 53% |
| 2018 Sonata | 210 | 56% |
| 2017 Sonata | 383 | 50% |
| 2016 Sonata | 450 | 62% |
| 2015 Sonata | 623 | 54% |
| 2014 Sonata | 301 | 40% |
| 2013 Sonata | 735 | 39% |
| 2012 Sonata | 567 | 36% |
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.