SFI SYSTEM, Diagnostic DTC:P0125

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

DESCRIPTION

Refer to DTC P0115 Click here.

DTC No. DTC Detection Condition Trouble Area
P0125

Engine coolant temperature does not reach closed loop enabling temperature for 20 minutes (this period varies with engine start engine coolant temperature)

(2 trip detection logic)

  • Cooling system

  • Engine coolant temperature sensor

  • Water inlet with thermostat

MONITOR DESCRIPTION

The resistance of the engine coolant temperature sensor varies in proportion to the actual engine coolant temperature. The ECM supplies a constant voltage to the sensor and monitors the signal output voltage of the sensor. The signal voltage output varies according to the changing resistance of the sensor. After the engine is started, the engine coolant temperature is monitored through this signal. If the engine coolant temperature sensor indicates that the engine is not yet warm enough for closed loop fuel control, despite a specified period of time having elapsed since the engine was started, the ECM interprets this as a malfunction in the sensor or cooling system and sets the DTC.

Example:

The engine coolant temperature is 5°C (41°F) at engine start. After about 5 minute running time, the engine coolant temperature sensor still indicates that the engine is not warm enough to begin closed loop fuel (air fuel ratio feedback) control. The ECM interprets this as a malfunction in the sensor or cooling system and sets the DTC.

MONITOR STRATEGY

Frequency of Operation Once per driving cycle

CONFIRMATION DRIVING PATTERN


  1. Leave the vehicle outside overnight.

  2. Connect the GTS to the DLC3.

  3. Turn the power switch on (IG) and turn the GTS on.

  4. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

  5. Check that the engine coolant temperature is 10°C (50°F) or less.

  6. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) Click here.

  7. Turn the power switch off and wait for at least 30 seconds.

  8. Turn the power switch on (IG) and turn the GTS on.

  9. Put the engine in inspection mode (maintenance mode) Click here.

  10. Start the engine.

  11. Wait 21 minutes or more.

  12. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

  13. Read Pending DTCs.

    Tech Tips


    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  14. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  15. Input the DTC: P0125.

  16. Check the DTC judgment result.

    GTS Display Description
    NORMAL

    • DTC judgment completed

    • System normal
    ABNORMAL

    • DTC judgment completed

    • System abnormal
    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions
    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU's memory limit

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

WIRING DIAGRAM

Refer to DTC P0115 Click here.

CAUTION / NOTICE / HINT

Tech Tips


  • If any of DTCs P0115, P0117 or P0118 are set simultaneously with DTC P0125, the engine coolant temperature sensor may have an open or a short circuit. Troubleshoot those DTCs first.

  • Read freeze frame data using the GTS. 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 ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0125)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    5. Read the DTCs.

      Result
      Result Proceed to
      DTC P0125 is output A
      DTC P0125 and other DTCs are output B

      Tech Tips

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


    B

    GO TO DTC CHART Click here

    A

  2. INSPECT WATER INLET WITH THERMOSTAT


    1. Inspect the water inlet with thermostat Click here.


    NG

    REPLACE WATER INLET WITH THERMOSTAT Click here

    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.


    OK

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

    NG

    REPAIR OR REPLACE COOLING SYSTEM