DTC    P0125    Insufficient Coolant Temperature for Closed Loop Fuel Control

for Preparation Click here


DESCRIPTION

A thermistor is built into the Engine Coolant Temperature (ECT) sensor, of which the resistance value varies according to the ECT.
The structure of the sensor and its connection to the ECM (Included in HV Control ECU) are the same as those of the Intake Air Temperature (IAT) sensor.

DTC No.
DTC Detection Condition
Trouble Area
P0125
Engine coolant temperature (ECT) does not reach closed-loop enable temperature for 20 minutes (this period varies with ECT when engine start)
  1. Engine coolant temperature sensor
  2. Cooling system
  3. Thermostat

WIRING DIAGRAM

Refer to DTC P0115 (Click here).

INSPECTION PROCEDURE

HINT:
  1. If any of DTCs P0115, P0116, P0117 or P0118 are set simultaneously with DTC P0125, the Engine Coolant Temperature (ECT) sensor may have an open or a short circuit. Troubleshoot those DTCs first.
  2. Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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.

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

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch ON.

  1. Turn the tester ON.

  1. Enter the following menus: Powertrain / Engine / DTC.

  1. Read DTCs.

    Result:

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

    HINT:
    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 (Click here).

  1. Check the valve opening temperature of the thermostat.

    Standard:
    80 to 84°C (176 to 183°F)

    HINT:
    In addition to the above check, confirm that the valve is completely closed when the temperature is below the standard.

  1. Reinstall the thermostat (Click here).



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 modifications.



NG
REPAIR OR REPLACE COOLING SYSTEM
OK

REPLACE ENGINE COOLANT TEMPERATURE SENSOR