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. The cooling fan ECUs control each cooling fan speed based on the duty cycle calculated by the ECM. By optimally controlling the cooling fan speed via the cooling fan ECUs based on the conditions of the vehicle, the ECM can achieve 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. Perform the Active Test according to the display on the GTS.

      OK
      Active Tester Operation Fan Operation
      ON Cooling fans operate
      OFF Cooling fans stop
      Result
      Result Proceed to
      OK A
      NG (Fan does not operate) B
      NG (No. 2 fan does not operate) C
      NG (Fan does not stop) D
      NG (No. 2 fan does not stop) E

    A

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

    C

    CHECK COOLING FAN SYSTEM (NO. 2 FAN) Click here

    D

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

    E

    CHECK HARNESS AND CONNECTOR (NO. 2 COOLING FAN ECU - ECM) Click here

    B

  2. CHECK COOLING FAN SYSTEM (FAN)


    1. Disconnect the A53 ECM connector.

    2. Turn the engine switch on (IG).

    3. Check the operation of the cooling fan.

      OK
      The cooling fan operates.
      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 POWER SOURCE)

    B006OUFC30
    *a

    Front view of wire harness connector

    (to Cooling Fan ECU)

    1. Disconnect the A10 cooling fan ECU 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
      A10-1 (+B1) - A10-3 (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 (COOLING FAN ECU AND NO. 2 COOLING FAN ECU - ECM)


    1. Disconnect the A53 ECM connector.

    2. Disconnect the A10 cooling fan ECU connector.

    3. Disconnect the A11 No. 2 cooling fan ECU connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A10-2 (SI), A11-2 (SI2) or A53-5 (RFC) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COOLING FAN ECU

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU AND NO. 2 COOLING FAN ECU - ECM)

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


    1. Disconnect the A10 cooling fan ECU connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A10-3 (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 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 (FAN NO. 1 RELAY POWER SOURCE CIRCUIT)


    1. B006L7AC05
      *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) - Body ground Engine switch on (IG) 11 to 14 V
      3 (FAN NO. 1 relay) - Body ground Always 11 to 14 V
      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 - FAN NO. 1 RELAY)


    1. Disconnect the A10 cooling fan ECU 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
      A10-1 (+B1) - 5 (FAN NO. 1 relay) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A10-1 (+B1) or 5 (FAN NO. 1 relay) - Body ground Always 10 kΩ or higher
      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 - FAN NO. 1 RELAY)

  10. CHECK COOLING FAN SYSTEM (NO. 2 FAN)


    1. Disconnect the A53 ECM connector.

    2. Turn the engine switch on (IG).

    3. Check the operation of the cooling fan.

      OK
      The cooling fan operates.
      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 (NO. 2 COOLING FAN ECU POWER SOURCE)

    B006OUFC31
    *a

    Front view of wire harness connector

    (to No. 2 Cooling Fan ECU)

    1. Disconnect the A11 No. 2 cooling fan ECU 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
      A11-1 (+B2) - A11-3 (E2) Engine switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (NO. 2 COOLING FAN ECU - BODY GROUND) Click here

    OK

  13. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU AND NO. 2 COOLING FAN ECU - ECM)


    1. Disconnect the A53 ECM connector.

    2. Disconnect the A10 cooling fan ECU connector.

    3. Disconnect the A11 No. 2 cooling fan ECU connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A10-2 (SI), A11-2 (SI2) or A53-5 (RFC) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 2 COOLING FAN ECU

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU AND NO. 2 COOLING FAN ECU - ECM)

  14. CHECK HARNESS AND CONNECTOR (NO. 2 COOLING FAN ECU - BODY GROUND)


    1. Disconnect the A11 No. 2 cooling fan ECU connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A11-3 (E2) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 2 COOLING FAN ECU - 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. B006MOXC02
      *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) - Body ground Engine switch on (IG) 11 to 14 V
      3 (FAN NO. 2 relay) - Body ground Always 11 to 14 V
      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 (NO. 2 COOLING FAN ECU - FAN NO. 2 RELAY)


    1. Disconnect the A11 No. 2 cooling fan ECU 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 (Check for Open)
      Tester Connection Condition Specified Condition
      A11-1 (+B2) - 5 (FAN NO. 2 relay) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A11-1 (+B2) or 5 (FAN NO. 2 relay) - Body ground Always 10 kΩ or higher
      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 (NO. 2 COOLING FAN ECU - FAN NO. 2 RELAY)

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


    1. Disconnect the A53 ECM connector.

    2. Disconnect the A10 cooling fan ECU connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A10-2 (SI) - A53-5 (RFC) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

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


    1. B006R3UC58
      *a

      Component without harness connected

      (Cooling Fan Motor)

      Disconnect the z9 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
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COOLING FAN ECU

    NG

    REPLACE COOLING FAN MOTOR Click here

  20. CHECK HARNESS AND CONNECTOR (NO. 2 COOLING FAN ECU - ECM)


    1. Disconnect the A53 ECM connector.

    2. Disconnect the A11 No. 2 cooling fan ECU connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A11-2 (SI2) - A53-5 (RFC) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 2 COOLING FAN ECU - ECM)

    OK

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


    1. B006R3UC59
      *a

      Component without harness connected

      (No. 2 Cooling Fan Motor)

      Disconnect the z8 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
      z8-1 (M-) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 2 COOLING FAN ECU

    NG

    REPLACE NO. 2 COOLING FAN MOTOR Click here