Toyota Vios/1.5E/2004 Faulty Code P0125

car just developed with check engine light and the faulty code was P0125, I took the vehicle to Toyota Lanka, the agent in Colombo and they replaced ECT sensor and both O2  and Oxygen sensors, but when I drove the vehicle for nearly 10 kms, the light came back with the same faulty code, P0125, the engine has not reached the required temperature level to enter closed-loop operation. As per Toyota Lanka now these sensors, ECT and Oxygen sensors readings are in order.

Could you please help me out to sort the issue, then I can talk to Toyota Lanka tomorrow again.


1 thought on “Toyota Vios/1.5E/2004 Faulty Code P0125”

  1. P0125 TOYOTA – Insufficient Coolant Temperature for Closed Loop Fuel Control

    Possible causes
    – Low engine coolant level
    – Engine Coolant Temperature (ECT) sensor harness is open or shorted
    – Engine Coolant Temperature (ECT) sensor electrical circuit poor connection
    – Faulty Engine Coolant Temperature (ECT) sensor
    – Faulty engine coolant thermostat

    When is the code detected?
    The voltage sent to Engine Control Module (ECM) from the sensor is not practical, even when some time has passed after starting the engine.

    P0125 TOYOTA Description
    The Engine Coolant Temperature (ECT) sensor is used to detect the engine coolant temperature. The sensor modifies a voltage signal from the Engine Control Module (ECM). The modified signal returns to the ECM as the engine coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.

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