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 ECUs to regulate the cooling fans. The cooling fan ECUs control each 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 ECUs, achieving both high cooling performance and quietness.

WIRING DIAGRAM

Refer to the System Diagram.

Click here

CAUTION / NOTICE / HINT

Note

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

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 Electric Cooling Fan.


      Powertrain > Engine > Active Test
      Tester Display
      Control the Electric Cooling Fan

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

      OK
      Tester Operation Fan Operation
      ON Cooling fans operate
      OFF Cooling fans stop
      Result
      Result Proceed to
      OK A
      NG (Main fan do not operate) B
      NG (Sub fan do not operate) C
      NG (Main fan do not stop) D
      NG (Sub fan do not stop) E

    6. Turn the engine switch off.


    A

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

    C

    CHECK COOLING FAN SYSTEM (FOR SUB FAN) Click here

    D

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

    E

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

    B

  2. CHECK COOLING FAN SYSTEM (FOR MAIN FAN)


    1. Disconnect the A13 ECM connector.

    2. Turn the engine switch on (IG).

    3. Check the operation of the cooling fan (for main fan).

      OK
      The cooling fan (for main fan) operates.

    4. Turn the engine switch off.

    5. Reconnect the A13 ECM connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

  3. INSPECT COOLING FAN MOTOR


    1. Inspect the cooling fan motor.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE COOLING FAN MOTOR Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU (FOR MAIN FAN) POWER SOURCE)

    B002EGNC63
    *a

    Front view of wire harness connector

    (to Cooling Fan ECU (for Main Fan))

    1. Disconnect the A31 cooling fan ECU (for main fan) connector.

    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
      A31-1 (+B1) - A31-3 (E1) Engine switch on (IG) 11 to 14 V

    4. Turn the engine switch off.

    5. Reconnect the A31 cooling fan ECU (for main fan) connector.

      Result
      Proceed to
      OK
      NG

    NG

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

    OK

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


    1. Disconnect the A31 cooling fan ECU (for main fan) connector.

    2. Disconnect the b1 cooling fan ECU (for sub fan) connector.

    3. Disconnect the A13 ECM connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A31-2 (SI), b1-2 (SI) or A13-26 (RFC) - Body ground Always 10 kΩ or higher

    5. Reconnect the A13 ECM connector.

    6. Reconnect the b1 cooling fan ECU (for sub fan) connector.

    7. Reconnect the A31 cooling fan ECU (for main fan) connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COOLING FAN ECU (FOR MAIN FAN)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU (FOR MAIN FAN AND FOR SUB FAN) - ECM)

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


    1. Disconnect the A31 cooling fan ECU (for main fan) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A31-3 (E1) - Body ground Always Below 1 Ω

    3. Reconnect the A31 cooling fan ECU (for main fan) connector.

      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  7. INSPECT FAN NO. 1 RELAY


    1. Inspect the FAN NO. 1 relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FAN NO. 1 RELAY

    OK

  8. CHECK HARNESS AND CONNECTOR HARNESS AND CONNECTOR (FAN NO. 1 RELAY POWER SOURCE CIRCUIT)


    1. B002E7IC01
      *1 NO. 2 Engine Room Relay Block
      *2 FAN NO. 1 relay

      Remove the FAN NO. 1 relay from the NO. 2 engine room relay block.

    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 NO. 1 relay holder) - Body ground Engine switch on (IG) 11 to 14 V
      3 (FAN NO. 1 relay holder) - Body ground Always 11 to 14 V

    4. Turn the engine switch off.

    5. Reinstall the FAN NO. 1 relay.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY POWER SOURCE CIRCUIT)

    OK

  9. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU (FOR MAIN FAN) - FAN NO. 1 RELAY)


    1. Disconnect the A31 cooling fan ECU (for main fan) connector.

    2. Remove the FAN NO. 1 relay from the NO. 2 engine room relay block.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A31-1 (+B1) - 5 (FAN NO. 1 relay holder) Always Below 1 Ω
      A31-1 (+B1) or 5 (FAN NO. 1 relay holder)- Body ground Always 10 kΩ or higher

    4. Reinstall the FAN NO. 1 relay.

    5. Reconnect the A31 cooling fan ECU (for main fan) connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY - BODY GROUND)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU (FOR MAIN FAN) - FAN NO. 1 RELAY)

  10. CHECK COOLING FAN SYSTEM (FOR SUB FAN)


    1. Disconnect the A13 ECM connector.

    2. Turn the engine switch on (IG).

    3. Check the operation of the cooling fan (for sub fan).

      OK
      The cooling fan (for sub fan) operates.

    4. Turn the engine switch off.

    5. Reconnect the A13 ECM connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

  11. INSPECT NO. 2 COOLING FAN MOTOR


    1. Inspect the No. 2 cooling fan motor.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 2 COOLING FAN MOTOR Click here

    OK

  12. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU (FOR SUB FAN) POWER SOURCE)

    B002EGNC64
    *a

    Front view of wire harness connector

    (to Cooling Fan ECU (for Sub Fan))

    1. Disconnect the b1 cooling fan ECU (for sub fan) connector.

    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
      b1-1 (+B) - b1-3 (GND) Engine switch on (IG) 11 to 14 V

    4. Turn the engine switch off.

    5. Reconnect the b1 cooling fan ECU (for sub fan) connector.

      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  13. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU (FOR MAIN FAN AND FOR SUB FAN) - ECM)


    1. Disconnect the A31 cooling fan ECU (for main fan) connector.

    2. Disconnect the b1 cooling fan ECU (for sub fan) connector.

    3. Disconnect the A13 ECM connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A31-2 (SI), b1-2 (SI) or A13-26 (RFC) - Body ground Always 10 kΩ or higher

    5. Reconnect the A13 ECM connector.

    6. Reconnect the b1 cooling fan ECU (for sub fan) connector.

    7. Reconnect the A31 cooling fan ECU (for main fan) connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COOLING FAN ECU (FOR SUB FAN)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU (FOR MAIN FAN AND FOR SUB FAN) - ECM)

  14. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU (FOR SUB FAN) - BODY GROUND)


    1. Disconnect the b1 cooling fan ECU (for sub fan) connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      b1-3 (E2) - Body ground Always Below 1 Ω

    3. Reconnect the b1 cooling fan ECU (for sub fan) connector.

      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  15. INSPECT FAN NO. 2 RELAY


    1. Inspect the FAN NO. 2 relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FAN NO. 2 RELAY

    OK

  16. CHECK HARNESS AND CONNECTOR (FAN NO. 2 RELAY POWER SOURCE CIRCUIT)


    1. B002CEMC01
      *1 NO. 2 Engine Room Relay Block
      *2 FAN NO. 2 relay

      Remove the FAN NO. 2 relay from the NO. 2 engine room relay block.

    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 NO. 2 relay holder) - Body ground Engine switch on (IG) 11 to 14 V
      3 (FAN NO. 2 relay holder) - Body ground Always 11 to 14 V

    4. Turn the engine switch off.

    5. Reinstall the FAN NO. 2 relay.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 2 RELAY POWER SOURCE CIRCUIT)

    OK

  17. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU (FOR SUB FAN) - FAN NO. 2 RELAY)


    1. Disconnect the b1 cooling fan ECU (for sub fan) connector.

    2. Remove the FAN NO. 2 relay from the NO. 2 engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      b1-1 (+B) - 5 (FAN NO. 2 relay holder) Always Below 1 Ω
      b1-1 (+B) or 5 (FAN NO. 2 relay holder)- Body ground Always 10 kΩ or higher

    4. Reinstall the FAN NO. 2 relay.

    5. Disconnect the b1 cooling fan ECU (for sub fan) connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 2 RELAY - BODY GROUND)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU (FOR SUB FAN) - FAN NO. 2 RELAY)

  18. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU (FOR MAIN FAN) - ECM)


    1. Disconnect the A31 cooling fan ECU (for main fan) connector.

    2. Disconnect the A13 ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A31-2 (SI) - A13-26 (RFC) Always Below 1 Ω

    4. Reconnect the A13 ECM connector.

    5. Reconnect the A31 cooling fan ECU (for main fan) connector.

      Result
      Proceed to
      OK
      NG

    NG

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

    OK

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


    1. Disconnect the z8 cooling fan motor connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      z8-1 (M+) - Body ground Always 10 kΩ or higher

    3. Reconnect the z8 cooling fan motor connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COOLING FAN ECU (FOR MAIN FAN)

    NG

    REPLACE COOLING FAN MOTOR Click here

  20. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU (FOR SUB FAN) - ECM)


    1. Disconnect the b1 cooling fan ECU (for sub fan) connector.

    2. Disconnect the A13 ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      b1-2 (SI) - A13-26 (RFC) Always Below 1 Ω

    4. Reconnect the A13 ECM connector.

    5. Reconnect the b1 cooling fan ECU (for sub fan) connector.

      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  21. CHECK HARNESS AND CONNECTOR (No. 2 COOLING FAN MOTOR - BODY GROUND)


    1. Disconnect the z9 No. 2 cooling fan motor connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      z9 - 1 (M+) - Body ground Always 10 kΩ or higher

    3. Reconnect the z9 No. 2 cooling fan motor connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COOLING FAN ECU (FOR SUB FAN)

    NG

    REPLACE NO. 2 COOLING FAN MOTOR Click here