P0128 on the 2019 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-EM-002H | 2020-08-07. Service bulletin. This bulletin provides a procedure for replacing the thermostat on certain 2019 Elantra vehicles. The thermostat may not function properly and may result in Diagnostic Trouble Codes P0128 or P2181. To correct this condition, follow the procedure outlined in this bulletin to replace the thermostat and air bleed the cooling system after refilling. No drivability issues are associated with this condition. |
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| 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. |
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.