P0128 on the 2019 Hyundai Ioniq
The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.
Nobody has written a description of this code yet.
| 20-FL-012H | 2021-01-09. Service bulletin. This bulletin provides information related to the Engine Control Module (ECM) software logic update for DTC P0128 “Coolant thermostat - Coolant temp Below thermostat regulating Temperature”. There is no drivability issue with this DTC. |
|---|---|
| 20-01-049H | 2021-01-09. Service bulletin. This bulletin provides information related to the Engine Control Module (ECM) software update for OBD communication test logic, and for DTC P0128 “Coolant thermostat - Coolant temp Below thermostat regulating Temperature”. There are no drivability related conditions. |
2 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.