Hyundai Sonata Hybrid 2020–2023 — technical service bulletin
Bulletin 23-EM-009H · NHTSA communication 10247605 · issued Dec 15, 2023
Technical service bulletin
communication type
Engine and Engine Cooling
component
2020–2023
model years
4
vehicle entries
Official summary
Certain 2020-2023MY Sonata Hybrid (DN8 HEV) vehicles may exhibit coolant leakage, engine overheating, and white smoke from the exhaust due to an internal leak at the Exhaust Heat Recovery System (EHRS) portion of the center muffler assembly. Follow the procedure outlined in this bulletin to repair this condition after confirming EHRS is leaking internally.
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.