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COOLING FAN SYSTEM Cooling Fan Circuit

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DTC Code DTC Name
  Cooling Fan Circuit
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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. The cooling fan speed is determined based on engine coolant temperature, air conditioner operating conditions, engine speed, and vehicle speed.

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WIRING DIAGRAM

Refer to System Diagram (Click here).

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INSPECTION PROCEDURE

Note:

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

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PROCEDURE


  1. Click here

    PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE ELECTRIC COOLING FAN)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch on (IG).

    3. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Electric Cooling Fan.

    4. Check the operation of the cooling fans while operating it using the tester.

      OK
      Tester Operation Specified Condition
      ON Cooling fans operated
      OFF Cooling fans stopped
      Result
      Result Proceed to
      OK A
      NG (Cooling fans do not operate) B
      NG (Cooling fans do not stop) C

  2. Click here

    INSPECT COOLING FAN MOTOR (COOLING FAN MOTOR AND NO. 2 COOLING FAN MOTOR)


    1. A017CDYE02

      Disconnect the cooling fan motor and No. 2 cooling fan motor connectors.

    2. Connect a battery positive (+) lead to each terminal 2 of the cooling fan motor and No. 2 cooling fan motor connectors, and connect a battery negative (-) lead to each terminal 1 of the cooling fan motor and No. 2 cooling fan motor connectors.

      OK
      The cooling fan motors operate.
      Result
      Result Proceed to
      OK A
      NG (Cooling fan motor) B
      NG (No. 2 Cooling fan motor) C

    3. Reconnect the cooling fan motor connectors.


  3. Click here

    CHECK HARNESS AND CONNECTOR (COOLING FAN ECU POWER SOURCE)


    1. A017CQIE03

      Disconnect the cooling fan ECU connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A9-3 (+B1) - A9-1 (E1) Ignition switch ON 11 to 14 V

    4. Reconnect the cooling fan ECU connector.


  4. Click here

    CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU)


    1. A017DRWE03

      Disconnect the ECM connector.

    2. Disconnect the cooling fan ECU connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      D56-6 (RFC) or A9-2 (SI) - Body ground Always 10 kΩ or higher

    4. Reconnect the cooling fan ECU connector.

    5. Reconnect the ECM connector.


  5. Click here

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


    1. A017CQIE04

      Disconnect the 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
      A9-1 (E1) - Body ground Always Below 1 Ω

    3. Reconnect the cooling fan ECU connector.


  6. Click here

    INSPECT RELAY (FAN MAIN)


    1. A017C0W

      Remove the FAN MAIN relay from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 No battery voltage applied to terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage applied to terminals 1 and 2 Below 1 Ω

    3. Reinstall the FAN MAIN relay.


  7. Click here

    CHECK HARNESS AND CONNECTOR (FAN MAIN RELAY POWER SOURCE)


    1. A017ENWE03

      Remove the FAN MAIN relay from the engine room relay block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3 (FAN MAIN relay) - Body ground Always 11 to 14 V

    3. Reinstall the FAN MAIN relay.


  8. Click here

    CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - FAN MAIN RELAY)


    1. A017D5KE03

      Remove the FAN MAIN relay from the engine room relay block.

    2. Disconnect the 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
      A9-3 (+B1) - 5 (FAN MAIN relay) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A9-3 (+B1) or 5 (FAN MAIN relay) - Body ground Always 10 kΩ or higher

    4. Reconnect the cooling fan ECU connector.

    5. Reinstall the FAN MAIN relay.


  9. Click here

    CHECK HARNESS AND CONNECTOR (FAN MAIN RELAY - BODY GROUND)


    1. A017ENWE03

      Remove the FAN MAIN relay from the engine room relay block.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      2 (FAN MAIN relay) - Body ground Always Below 1 Ω

    3. Reinstall the FAN MAIN relay.


  10. Click here

    CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU)


    1. A017DRWE03

      Disconnect the ECM connector.

    2. Disconnect the cooling fan ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D56-6 (RFC) - A9-2 (SI) Always Below 1 Ω

    4. Reconnect the cooling fan ECU connector.

    5. Reconnect the ECM connector.


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    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLEClick here

  12. Click here

    REPLACE COOLING FAN MOTORClick here

  13. Click here

    REPLACE NO. 2 COOLING FAN MOTORClick here

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

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    REPLACE COOLING FAN ECUClick here

  16. Click here

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

  17. Click here

    REPLACE RELAY (FAN MAIN RELAY)

  18. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN MAIN RELAY - BATTERY)

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

  20. Click here

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

  21. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN MAIN RELAY - ENGINE ROOM JUNCTION BLOCK ASSEMBLY)