COOLING FAN SYSTEM Cooling Fan Circuit

DESCRIPTION

The ECM calculates an appropriate cooling fan speed based on the engine coolant temperature, air conditioning switch condition, refrigerant pressure, engine speed and vehicle speed, and sends the signals to the cooling fan ECU to regulate the cooling fans. The cooling fan ECU controls the cooling fan speed based on the duty ratio signal sent from the ECM. By basing its control on the operating conditions, the ECM can control the fan speed optimally using the cooling fan ECU, achieving both high cooling performance and quietness.

WIRING DIAGRAM

B00770GE01

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. PERFORM ACTIVE TEST USING GTS (CONTROL THE ELECTRIC COOLING FAN)


    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 (Cooling fans do not operate) B
      NG (Cooling fans do not stop) C

    A

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

    C

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

    B

  2. CHECK COOLING FAN SYSTEM


    1. Disconnect the F66 ECM connector.

    2. Turn the engine switch on (IG).

    3. Check the operation of the cooling fans.

      OK
      Cooling fans operate.
      Result
      Result
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

  3. INSPECT COOLING FAN MOTOR (COOLING FAN MOTOR LH AND COOLING FAN MOTOR RH)


    1. Inspect the cooling fan motor LH and cooling fan motor RH.

      Click here

      Result
      Result Proceed to
      OK A
      NG (Cooling fan motor LH) B
      NG (Cooling fan motor RH) C

    B

    REPLACE COOLING FAN MOTOR LH Click here

    C

    REPLACE COOLING FAN MOTOR RH Click here

    A

  4. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. Disconnect the A38 cooling fan ECU connector.

    2. Turn the engine switch on (IG).

    3. B00769UC35
      *a

      Front view of wire harness connector

      (to Cooling Fan ECU)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A38-3 (+B1) - A38-1 (E1) Engine switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  5. CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU)


    1. Disconnect the F66 ECM connector.

    2. Disconnect the A38 cooling fan ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F66-136 (RFC) or A38-2 (SI) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COOLING FAN ECU

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - COOLING FAN ECU)

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


    1. Disconnect the A38 cooling fan ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A38-1 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU - BODY GROUND)

    OK

  7. INSPECT FAN RELAY


    1. Inspect the FAN relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FAN RELAY

    OK

  8. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. B0076G7C03
      *1 No. 2 Engine Room Relay Block and No. 2 Junction Block Assembly
      *2 FAN relay

      Remove the FAN relay from the No. 2 engine room relay block and No. 2 junction block assembly.

    2. Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      1 (FAN relay holder) - Body ground Engine switch on (IG) 11 to 14 V
      3 (FAN relay holder) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  9. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - FAN RELAY)


    1. Disconnect the A38 cooling fan ECU connector.

    2. Remove the FAN relay from the No. 2 engine room relay block and No. 2 junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A38-3 (+B1) - 5 (FAN relay holder) Always Below 1 Ω
      A38-3 (+B1) or 5 (FAN relay holder) - Body ground Always 10 kΩ or higher
      Result
      Result
      OK
      NG

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN RELAY - BODY GROUND)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU - FAN RELAY)

  10. CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU)


    1. Disconnect the F66 ECM connector.

    2. Disconnect the A38 cooling fan ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F66-136 (RFC) - A38-2 (SI) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - COOLING FAN ECU)

    OK

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


    1. Disconnect the z9 cooling fan motor LH connector.

    2. B0075C0C32
      *a

      Rear view of wire harness connector

      (Cooling fan motor LH)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      z9-1 (M-) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE COOLING FAN MOTOR LH Click here

    OK

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


    1. Disconnect the z10 cooling fan motor RH connector.

    2. B0074O3C45
      *a

      Rear view of wire harness connector

      (Cooling fan motor RH)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      z10-1 (M-) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COOLING FAN ECU

    NG

    REPLACE COOLING FAN MOTOR RH Click here