FixVault

DTC Detection Logic

Engine coolant temperature has not risen enough to open the thermostat even though the engine has run long enough.

This is due to a leak in the seal or the thermostat being stuck open.

DTC

CONSULT screen terms

(Trouble diagnosis content)

DTC detection condition

P0128

THERMSTAT FNCTN

[Coolant thermostat (coolant temperature below thermostat regulating temperature)]

Diagnosis condition

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Signal (terminal)

Engine coolant temperature sensor signal

Threshold

The engine coolant temperature does not reach to specified temperature even though the engine has run long enough.

Diagnosis delay time

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