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 signals to the cooling fan ECU to regulate the cooling fan. The cooling fan ECU controls the cooling fan speed based on the duty ratio signal sent from the ECM.

WIRING DIAGRAM

Refer to System Diagram Click here.

INSPECTION PROCEDURE

Note

Inspect the fuses for circuits related to this system before performing the following inspection 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. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Electric Cooling Fan.

    4. Check the operation of the cooling fan while operating it using the GTS.

      OK
      GTS Operation Fan Operation
      ON Cooling fan operates
      OFF Cooling fan stops
      Result
      Result Proceed to
      OK A
      Cooling fan does not operate B
      Cooling fan does not stop C

    B

    CHECK COOLING FAN SYSTEM Click here

    C

    INSPECT COOLING FAN MOTOR Click here

    A

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

  2. CHECK COOLING FAN SYSTEM


    1. A01FGX1E10
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to ECM)

      Disconnect the A19 ECM connector.

    2. Turn the engine switch on (IG).

    3. Check the operation of the cooling fan.

      OK
      The cooling fan operates.

    4. Reconnect the ECM connector.


    NG

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

    OK

    REPLACE ECM Click here

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


    1. Disconnect the cooling fan ECU connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A19-19 (RFC) - B4-2 (SI) Always Below 1 Ω
      A19-19 (RFC) or B4-2 (SI) - Body ground Always 10 kΩ or higher

    4. Reconnect the cooling fan ECU connector.

    5. Reconnect the ECM connector.


    NG

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

    OK

  4. INSPECT COOLING FAN MOTOR


    1. Inspect the cooling fan motor and No. 2 cooling fan motor Click here.

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

    B

    REPLACE COOLING FAN MOTOR Click here

    C

    REPLACE NO. 2 COOLING FAN MOTOR Click here

    A

  5. CHECK COOLING FAN ECU (POWER SOURCE)


    1. A01FESGE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Cooling Fan ECU)

      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
      B4-3 (+B1) - B4-1 (E1) Engine switch on (IG) 11 to 14 V

    4. Reconnect the cooling fan ECU connector.


    NG

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

    OK

    REPLACE COOLING FAN ECU

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


    1. Disconnect the cooling fan ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B4-1 (E1) - Body ground Always Below 1 Ω

    3. Reconnect the cooling fan ECU connector.


    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.


    NG

    REPLACE FAN NO. 1 RELAY

    OK

  8. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - FAN NO. 1 RELAY)


    1. Disconnect the 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
      Tester Connection Condition Specified Condition
      B4-3 (+B1) - Relay block FAN NO. 1 relay terminal (3) Always Below 1 Ω
      B4-3 (+B1) or Relay block FAN NO. 1 relay terminal (3) - Body ground Always 10 kΩ or higher

    4. Reinstall the FAN NO. 1 relay.

    5. Reconnect the cooling fan ECU connector.


    NG

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

    OK

  9. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY - BODY GROUND)


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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Relay block FAN NO. 1 relay terminal (2) - Body ground Always Below 1 Ω

    3. Reinstall the FAN NO. 1 relay.


    NG

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

    OK

  10. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY - BATTERY)


    1. A01FHLRE01
      Text in Illustration
      *1 Engine Room No. 2 Relay Block
      *2 Relay Block FAN NO. 1 Relay Terminals

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      Relay block FAN NO. 1 relay terminal (5) - Body ground Always 11 to 14 V

    3. Reinstall the FAN NO. 1 relay.


    NG

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

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY - LH-IG1 RELAY1)

  11. INSPECT COOLING FAN MOTOR


    1. Disconnect the cooling fan motor connector.

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Cooling fan motor connector terminal (1) - Body ground Always 10 kΩ or higher
      No. 2 cooling fan motor connector terminal (1) - Body ground Always 10 kΩ or higher
      Result
      Result Proceed to
      OK A
      NG (Cooling fan motor) B
      NG (No. 2 cooling fan motor) C

    4. Reconnect the cooling fan motor connector.

    5. Reconnect the No. 2 cooling fan motor connector.


    B

    REPLACE COOLING FAN MOTOR Click here

    C

    REPLACE NO. 2 COOLING FAN MOTOR Click here

    A

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


    1. 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
      A19-19 (RFC) - B4-2 (SI) Always Below 1 Ω
      A19-19 (RFC) or B4-2 (SI) - Body ground Always 10 kΩ or higher

    4. Reconnect the cooling fan ECU connector.

    5. Reconnect the ECM connector.


    NG

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

    OK

  13. REPLACE COOLING FAN ECU


    1. Replace the cooling fan ECU.


    NEXT

  14. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Check the cooling fan operation.

      OK
      Malfunction has been repaired successfully.

    NG

    REPLACE ECM Click here

    OK

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