COOLING FAN SYSTEM Cooling Fan Circuit

TECHNICAL DESCRIPTION

To control the cooling fans, the ECM turns on or off the cooling fan relays based on the engine coolant temperature, air conditioning switch, refrigerant pressure, engine speed and vehicle speed signals.

The ECM turns on or off the fan relays to switch the cooling fan motor circuit between the series circuit and parallel circuit, controlling the cooling fan motor speed in 2 steps.

WIRING DIAGRAM

Refer to System Diagram Click here.

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. CHECK FAN NO. 1 RELAY


    1. A005JJDE01

      Remove the FAN No. 1 relay from the engine room main relay block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      FAN No. 1 relay terminal 3 - Body ground Always 11 to 14V
      Text in Illustration
      *1 Engine Room Main Relay Block
      *2 FAN No. 1 Relay

    3. Reinstall the FAN No. 1 relay.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  2. CHECK ENGINE ROOM MAIN RELAY BLOCK


    1. A005II7E03

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

    2. Turn the Ignition switch to ON.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      FAN No. 1 relay terminal 1 - Body ground Ignition switch ON 11 to 14V
      FAN No. 2 relay terminal 2 - Body ground Ignition switch ON 11 to 14V
      Text in Illustration
      *1 Engine Room Main Relay Block
      *2 FAN No. 1 Relay
      *3 FAN No. 2 Relay

    4. Reinstall the FAN No. 1 relay and FAN No. 2 relay.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  3. INSPECT FAN NO. 1 RELAY


    1. Inspect the FAN No. 1 relay Click here.


    NG

    REPLACE FAN NO. 1 RELAY

    OK

  4. INSPECT FAN NO. 2 RELAY


    1. Inspect the FAN No. 2 relay Click here.


    NG

    REPLACE FAN NO. 2 RELAY

    OK

  5. INSPECT COOLING FAN RESISTOR


    1. Inspect the cooling fan resistor Click here.


    NG

    REPLACE COOLING FAN RESISTOR

    OK

  6. CHECK WIRE HARNESS AND CONNECTOR (FAN NO. 2 RELAY - BODY GROUND)


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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      FAN No. 2 relay terminal 5 - Body ground Always Below 1 Ω

    3. Reinstall the FAN No. 2 relay.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  7. CHECK WIRE HARNESS AND CONNECTOR (COOLING FAN RESISTOR - BODY GROUND)


    1. Disconnect the cooling fan resistor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A22-1 (-) - Body ground Always Below 1 Ω

    3. Connect the cooling fan resistor connector.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  8. CHECK WIRE HARNESS AND CONNECTOR (FAN NO. 2 RELAY - COOLING FAN RESISTOR)


    1. Disconnect the cooling fan resistor connector.

    2. Remove the FAN No. 2 relay from the engine room main 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
      FAN No. 2 relay terminal 4 - A22-2 (+) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A22-2 (+) or FAN No. 2 relay terminal 4 - Body ground Always 10 kΩ or higher

    4. Reinstall the FAN No. 2 relay.

    5. Reconnect the cooling fan resistor connector.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  9. CHECK COOLING FAN MOTOR


    1. Inspect the cooling fan motor Click here.


    NG

    REPLACE COOLING FAN MOTOR Click here

    OK

  10. CHECK WIRE HARNESS AND CONNECTOR (COOLING FAN MOTOR - FAN NO. 1 RELAY)


    1. Disconnect the cooling fan motor connector.

    2. Remove the FAN No. 1relay from the engine room main 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
      A21-2 - FAN No. 1 relay terminal 5 Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A21-2 or FAN No. 1 relay terminal 5 - Body ground Always 10 kΩ or higher

    4. Reinstall the FAN No. 1 relay.

    5. Reconnect the cooling fan motor connector.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  11. CHECK WIRE HARNESS AND CONNECTOR (COOLING FAN MOTOR - FAN NO. 2 RELAY)


    1. Disconnect the cooling fan motor connector.

    2. Remove the FAN No. 2 relay from the engine room main 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
      A21-1 - FAN No. 2 relay terminal 3 Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A21-1 or FAN No. 2 relay terminal 3 - Body ground Always 10 kΩ or higher

    4. Reinstall the FAN No. 2 relay.

    5. Reconnect the cooling fan motor connector.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  12. CHECK WIRE HARNESS AND CONNECTOR (ENGINE ROOM MAIN RELAY BLOCK - ECM)


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

    2. Disconnect the 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
      A58-8 (FANH) - FAN No. 2 relay terminal 1 Always Below 1 Ω
      A58-7 (FANL) - FAN No. 1 relay terminal 2 Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A58-8 (FANH) or FAN No. 2 relay terminal 1 - Body ground Always 10 kΩ or higher
      A58-7 (FANL) or FAN No. 1 relay terminal 2 - Body ground Always 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reinstall the FAN No. 1 relay and FAN No. 2 relay.


    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR