P0128 on the 2020 Hyundai Elantra
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-007H | 2020-08-07. Service bulletin. This bulletin provides information related to an ECM (Engine Control Module) software update for DTC P0128: Coolant Thermostat (Coolant Temp below Thermostat Regulating Temperature) logic revision. There are no drivability symptoms associated with DTC P0128. |
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1 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.