COOLING FAN SYSTEM Cooling Fan Circuit

DESCRIPTION

The ECM calculates an appropriate cooling fan speed based on the engine coolant temperature, air conditioning switch status, refrigerant pressure, engine speed and vehicle speed, and sends a signal to the cooling fan ECUs (cooling fan motors). The cooling fan ECUs (cooling fan motors) steplessly control the speed of the cooling fans based on the duty cycle signal sent from the ECM. By sending signals to the cooling fan ECUs (cooling fan motors) in accordance with the driving conditions and by controlling the cooling fan speed optimally with the ECM, both high cooling performance and quietness are ensured.

WIRING DIAGRAM

B006MQRE01

CAUTION / NOTICE / HINT

Note


  • Inspect the fuses for circuits related to this system before performing the following procedure.

  • Make sure to perform the necessary procedures (adjustment, calibration, initialization, or registration) after parts related to the cooling fan system have been removed/installed or replaced.

    Click here

PROCEDURE


  1. CHECK COOLING FAN SYSTEM


    1. Disconnect the D110 ECM connector.

    2. Turn the engine switch on (IG).

    3. Check the operation of the cooling fans.

      OK
      The cooling fans operate.
      Result
      Result Proceed to
      OK A
      NG (fan LH does not operate) B
      NG (fan RH does not operate) C
      NG (fans do not operate) D

    B

    CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH - BODY GROUND) Click here

    C

    CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR RH - BODY GROUND) Click here

    D

    CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH AND COOLING FAN MOTOR RH POWER SOURCE) Click here

    A

  2. PERFORM ACTIVE TEST USING GTS (CONTROL THE ENGINE COOLING FAN DUTY RATIO)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Active Test / Control the Engine Cooling Fan Duty Ratio.


      Powertrain > Engine > Active Test
      Tester Display
      Control the Engine Cooling Fan Duty Ratio

    5. Check the operation of the cooling fans while operating them using the GTS.

      OK
      Tester Operation Fan Operation
      30 - 100% Cooling fans operate
      0% Cooling fans stop
      Result
      Result Proceed to
      OK A
      NG (fans do not operate) B
      NG (fan LH does not stop) C
      NG (fan RH fan does not stop) D
      NG (fans do not stop) E

    A

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    B

    REPLACE ECM Click here

    D

    CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR RH - ECM) Click here

    E

    CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH OR COOLING FAN MOTOR RH - ECM) Click here

    C

  3. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH - ECM)


    1. Disconnect the A72 cooling fan motor LH connector.

    2. Disconnect the D110 ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A72-3 (SI) - D110-136 (RFC) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COOLING FAN MOTOR LH Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  4. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR RH - ECM)


    1. Disconnect the p1 cooling fan motor RH connector.

    2. Disconnect the D110 ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      p1-3 (SI) - D110-136 (RFC) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COOLING FAN MOTOR RH Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  5. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH OR COOLING FAN MOTOR RH - ECM)


    1. Disconnect the A72 cooling fan motor LH connector.

    2. Disconnect the p1 cooling fan motor RH connector.

    3. Disconnect the D110 ECM connector.

    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A72-3 (SI) or p1-3 (SI) - D110-136 (RFC) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH - BODY GROUND)


    1. Disconnect the A72 cooling fan motor LH connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A72-2 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH POWER SOURCE)


    1. Disconnect the A72 cooling fan motor LH connector.

    2. B006NGQC30
      *a

      Front view of wire harness connector

      (to Cooling Fan Motor LH)

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A72-1 (+B1) - A72-2 (E1) Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN MOTOR LH - BATTERY)

    OK

  8. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH POWER SOURCE)


    1. Disconnect the A72 cooling fan motor LH connector.

    2. Turn the engine switch on (IG).

    3. B006NGQC31
      *a

      Front view of wire harness connector

      (to Cooling Fan Motor LH)

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A72-4 (IGS1) - A72-2 (E1) Engine switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COOLING FAN MOTOR LH Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN MOTOR LH - EFI-MAIN RELAY)

  9. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR RH - BODY GROUND)


    1. Disconnect the p1 cooling fan motor RH connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      p1-2 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR RH POWER SOURCE)


    1. Disconnect the p1 cooling fan motor RH connector.

    2. B006NGQC36
      *a

      Front view of wire harness connector

      (to Cooling Fan Motor RH)

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      p1-1 (+B) - p1-2 (GND) Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN MOTOR RH - BATTERY)

    OK

  11. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR RH POWER SOURCE)


    1. Disconnect the p1 cooling fan motor RH connector.

    2. Turn the engine switch on (IG).

    3. B006NGQC37
      *a

      Front view of wire harness connector

      (to Cooling Fan Motor RH)

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      p1-4 (IG) - p1-2 (GND) Engine switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COOLING FAN MOTOR RH Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN MOTOR RH - EFI-MAIN RELAY)

  12. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH AND COOLING FAN MOTOR RH POWER SOURCE)


    1. Disconnect the A72 cooling fan motor LH connector.

    2. Disconnect the p1 cooling fan motor RH connector.

    3. Turn the engine switch on (IG).

    4. B006NGQC34
      *1 Cooling Fan Motor LH
      *2 Cooling Fan Motor RH
      *a

      Front view of wire harness connector

      (to Cooling Fan Motor LH and Cooling Fan Motor RH)

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A72-4 (IGS1) - A72-2 (E1) Engine switch on (IG) 11 to 14 V
      p1-4 (IG) - p1-2 (GND) Engine switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH OR COOLING FAN MOTOR RH - EFI-MAIN RELAY) Click here

    OK

  13. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH OR COOLING FAN MOTOR RH - ECM)


    1. Disconnect the A72 cooling fan motor LH connector.

    2. Disconnect the p1 cooling fan motor RH connector.

    3. Disconnect the D110 ECM connector.

    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A72-3 (SI), p1-3 (SI) or D110-136 (RFC) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN MOTOR LH AND COOLING FAN MOTOR RH - BATTERY)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN MOTOR LH AND COOLING FAN MOTOR RH - ECM)

  14. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH OR COOLING FAN MOTOR RH - EFI-MAIN RELAY)


    1. Disconnect the A72 cooling fan motor LH connector.

    2. Disconnect the p1 cooling fan motor RH connector.

    3. Remove the EFI-MAIN relay, A/F relay and EFI-MAIN NO. 2 relay from the No. 1 engine room relay block assembly.

      Tech Tips

      Remove the A/F relay and EFI-MAIN NO. 2 relay connected between the checked terminals as the coil inside the relay influences the measurement value.

    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A72-4 (IGS1) or p1-4 (IG) - 5 (EFI-MAIN relay) Always Below 1 Ω
      Result
      Result
      OK
      NG

    OK

    CHECK ECM POWER SOURCE CIRCUIT Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR