COOLING FAN SYSTEM Cooling Fan Circuit

DESCRIPTION

To control the cooling fan, 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 control the cooling fan motor speed in 2 steps.

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.

  • Before replacing the ECM, refer to Service Bulletin.

PROCEDURE


  1. INSPECT NO. 1 ENGINE ROOM RELAY BLOCK (FAN NO. 1 RELAY)


    1. Remove the cooling fan relay (FAN NO. 1 relay) from the No. 1 engine room relay block.

    2. A0048QPC01
      *1 No. 1 Engine Room Relay Block
      *2 Cooling Fan Relay (FAN NO. 1 Relay)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3 (Cooling fan relay (FAN NO. 1 relay)) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. INSPECT NO. 1 ENGINE ROOM RELAY BLOCK (FAN NO. 1 RELAY AND FAN NO. 2 RELAY)


    1. Remove the cooling fan relay (FAN NO. 1 relay) and No. 2 cooling fan relay (FAN NO. 2 relay) from the No. 1 engine room relay block.

    2. Turn the Ignition switch to ON.

    3. A0048N8C01
      *1 No. 1 Engine Room Relay Block
      *2 Cooling Fan Relay (FAN NO. 1 Relay)
      *3 No. 2 Cooling Fan Relay (FAN NO. 2 Relay)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      1 (Cooling fan relay (FAN NO. 1 relay)) - Body ground Ignition switch ON 11 to 14 V
      1 (No. 2 cooling fan relay (FAN NO. 2 relay)) - Body ground Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT FAN NO. 1 RELAY


    1. Inspect the cooling fan relay (FAN NO. 1 relay).

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE COOLING FAN RELAY (FAN NO. 1 RELAY)

    OK

  4. INSPECT FAN NO. 2 RELAY


    1. Inspect the No. 2 cooling fan relay (FAN NO. 2 relay).

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 2 COOLING FAN RELAY (FAN NO. 2 RELAY)

    OK

  5. INSPECT COOLING FAN RESISTOR


    1. Inspect the cooling fan resistor.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE COOLING FAN RESISTOR Click here

    OK

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


    1. Remove the No. 2 cooling fan relay (FAN NO. 2 relay) from the No. 1 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
      5 (No. 2 cooling fan relay (FAN NO. 2 relay)) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the A22 cooling fan resistor connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A22-1 (-) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the A22 cooling fan resistor connector.

    2. Remove the No. 2 cooling fan relay (FAN NO. 2 relay) from the No. 1 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
      A22-2 (+) - 4 (No. 2 cooling fan relay (FAN NO. 2 relay)) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A22-2 (+) or 4 (No. 2 cooling fan relay (FAN NO. 2 relay)) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. 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

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


    1. Disconnect the A21 cooling fan motor connector.

    2. Remove the cooling fan relay (FAN NO. 1 relay) from the No. 1 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
      A21-2 - 5 (Cooling fan relay (FAN NO. 1 relay)) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A21-2 or 5 (Cooling fan relay (FAN NO. 1 relay)) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the A21 cooling fan motor connector.

    2. Remove the No. 2 cooling fan relay (FAN NO. 2 relay) from the No. 1 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
      A21-1 - 3 (No. 2 cooling fan relay (FAN NO. 2 relay)) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A21-1 or 3 (No. 2 cooling fan relay (FAN NO. 2 relay)) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  12. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK - ECM)


    1. Remove the cooling fan relay (FAN NO. 1 relay) and No. 2 cooling fan relay (FAN NO. 2 relay) from the No. 1 engine room relay block.

    2. Disconnect the A58 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
      2 (Cooling fan relay (FAN NO. 1 relay)) - A58-7 (FANL) Always Below 1 Ω
      2 (No. 2 cooling fan relay (FAN NO. 2 relay)) - A58-8 (FANH) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      2 (Cooling fan relay (FAN NO. 1 relay)) or A58-7 (FANL) - Body ground Always 10 kΩ or higher
      2 (No. 2 cooling fan relay (FAN NO. 2 relay)) or A58-8 (FANH) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR