P0115 · blink 42 – Engine Coolant Temperature Sensor (Ect) Circuit Malfunc

System: Engine control (EFI)
Dashboard light: Check engine light (MIL)
Check-engine blink code: 42
Applies to: 1KR-FE: M300 (Sirion export = JDM Boon M300S/M301S(4WD? see gaps) & Passo KGC10/KGC15). JDM-spec ECU not separately documented | K3-VE: M301 (Sirion 1.3 = JDM Boon M310S? / Passo QNC10)
Description: Engine Coolant Temperature Sensor (Ect) Circuit Malfunc
Detection / symptoms: Detection: 1.When the signals from the water temperature sensor are not outputted continuously after starting over a certain length of time:
Possible causes: Trouble area: 1.Open wire or short circuit in the engine coolant temperature sensor circuit 2.Engine coolant temperature sensor 3.EFI ECU
What to check: Checking points: 1.Are the signals from the water temperature sensor inputted to the EFI ECU? 2.Is the harness between the water temperature sensor and the EFI ECU normal? 3.Is the output of the water temperature sensor normal?; Unit check B8-220: THW-E2 -20C 15.04k / 20C 2.45k / 80C 0.318k / 110C 0.142k ohm
Confidence: high (factory manual, export spec)

From the factory service material. Clear the code and test-drive to confirm it returns. Search all fault codes · Common problems · Warning lights