SFI SYSTEM (w/ Electronic Throttle Control System), Diagnostic DTC:P0125

DTC Code DTC Name
P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control

DESCRIPTION

A thermistor is built into the engine coolant temperature sensor and changes its resistance value according to the engine coolant temperature. The structure of the sensor and connection to the ECM is the same as that of the intake air temperature sensor.

DTC No. DTC Detection Condition Trouble Area
P0125 Engine coolant temperature does not reach 9.75°C (49.55°F), temperature at which feedback starts, despite specified length of time* having elapsed since engine start (3 trip detection logic)

  • Engine coolant temperature sensor

  • Thermostat

  • Cooling system

*: Engine idles for 10 minutes.

INSPECTION PROCEDURE

Tech Tips

Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE


  1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0125)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the intelligent tester ON.

    3. Select the following menu items: Powertrain / Engine and ECT / DTC.

    4. Read DTCs.

      Result
      Display (DTC Output) Proceed To
      P0125 A
      P0125 and other DTCs B

      Tech Tips

      If any DTCs other than P0125 are output, troubleshoot those DTCs first.


    B

    GO TO DTC CHART

    A

  2. INSPECT THERMOSTAT


    1. Remove the thermostat.

    2. Check the valve opening temperature of the thermostat.

      Standard
      The valve opening temperature is 80 to 84°C (176 to 183°F)

      Tech Tips

      Also check that the valve is completely closed at a temperature under the opening temperature shown above.

    3. Reinstall the thermostat.


    NG

    REPLACE THERMOSTAT

    OK

  3. CHECK COOLING SYSTEM


    1. Check for defects in the cooling system that might cause the system to be too cold, such as abnormal radiator fan operation or any modification.


    NG

    REPAIR OR REPLACE COOLING SYSTEM

    OK

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR