COOLING FAN SYSTEM Cooling Fan Circuit

DESCRIPTION

The ECM turns the fan relays on or off using signals calculated from the engine coolant temperature, air conditioning switch (on/off), air conditioning refrigerant pressure, engine speed, and vehicle speed signals.

The ECM switches the circuit of the cooling fan motors between series and parallel by turning the fan relays on or off in order to control the speed of the cooling fan motors in two 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. PERFORM ACTIVE TEST USING GTS (CONTROL THE ELECTRIC COOLING FAN)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

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

    5. Check the operation of the cooling fans while operating them using the GTS.

      OK
      GTS Operation Specified Condition
      ON Fans operate
      OFF Fans do not operate

    OK

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

    NG

  2. INSPECT ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY (FAN NO. 1 RELAY, FAN NO. 2 RELAY AND FAN NO. 3 RELAY VOLTAGE)


    1. A005F1ME02
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 FAN No. 1 Relay
      *3 FAN No. 2 Relay
      *4 FAN No. 3 Relay

      Remove the FAN No. 1 relay, FAN No. 2 relay and FAN No. 3 relay from the engine room relay block and junction block assembly.

    2. Turn the power 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 Power switch on (IG) 11 to 14 V
      1 (FAN No. 2 relay) - Body ground Power switch on (IG) 11 to 14 V
      1 (FAN No. 3 relay) - Body ground Power switch on (IG) 11 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY - NO. 2 INTEGRATION RELAY) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY - ECM)


    1. Remove the FAN No. 1 relay, FAN No. 2 relay and FAN No. 3 relay from the engine room relay block and junction block assembly.

    2. Disconnect the A57 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (FAN No. 1 relay) - A57-22 (FANH) Always Below 1 Ω
      2 (FAN No. 2 relay) - A57-22 (FANH) Always Below 1 Ω
      2 (FAN No. 3 relay) - A57-21 (FANL) Always Below 1 Ω
      2 (FAN No. 1 relay) or A57-22 (FANH) - Body ground Always 10 kΩ or higher
      2 (FAN No. 2 relay) or A57-22 (FANH) - Body ground Always 10 kΩ or higher
      2 (FAN No. 3 relay) or A57-21 (FANL) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY - ECM)

    OK

  4. INSPECT ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY (FAN NO. 1 RELAY AND FAN NO. 3 RELAY VOLTAGE)


    1. A005CQ2E01
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 FAN No. 1 Relay
      *3 FAN No. 3 Relay

      Remove the FAN No. 1 relay and FAN No. 3 relay from the engine room relay block and junction block assembly.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3 (FAN No. 1 relay) - Body ground Power switch off 11 to 14 V
      5 (FAN No. 3 relay) - Body ground Power switch off 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (AUXILIARY BATTERY - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)

    OK

  5. INSPECT FAN NO. 1 RELAY


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


    NG

    REPLACE FAN NO. 1 RELAY

    OK

  6. INSPECT FAN NO. 2 RELAY


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


    NG

    REPLACE FAN NO. 2 RELAY

    OK

  7. INSPECT FAN NO. 3 RELAY


    1. Inspect the FAN No. 3 relay Click here.


    NG

    REPLACE FAN NO. 3 RELAY

    OK

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


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

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

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 2 RELAY - BODY GROUND)

    OK

  9. INSPECT COOLING FAN MOTOR


    1. Inspect the cooling fan motor Click here.


    NG

    REPLACE COOLING FAN MOTOR Click here

    OK

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


    1. Disconnect the A5 cooling fan motor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A5-1 - Body ground Always Below 1 Ω

    NG

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

    OK

  11. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)


    1. Disconnect the A5 cooling fan motor connector.

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A5-2 - 5 (FAN No. 1 relay) Always Below 1 Ω
      A5-2 - 4 (FAN No. 2 relay) Always Below 1 Ω
      A5-2 or 5 (FAN No. 1 relay) - Body ground Always 10 kΩ or higher
      A5-2 or 4 (FAN No. 2 relay) - Body ground Always 10 kΩ or higher

      Tech Tips

      Make sure that there are no short circuits to the auxiliary battery.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)

    OK

  12. INSPECT NO. 2 COOLING FAN MOTOR


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


    NG

    REPLACE NO. 2 COOLING FAN MOTOR Click here

    OK

  13. CHECK HARNESS AND CONNECTOR (NO. 2 COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)


    1. Disconnect the A6 No. 2 cooling fan motor connector.

    2. Remove the FAN No. 2 relay and FAN No. 3 relay from the engine room relay block and junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A6-1 - 3 (FAN No. 2 relay) Always Below 1 Ω
      A6-2 - 3 (FAN No. 3 relay) Always Below 1 Ω
      A6-1 or 3 (FAN No. 2 relay) - Body ground Always 10 kΩ or higher
      A6-2 or 3 (FAN No. 3 relay) - Body ground Always 10 kΩ or higher

      Tech Tips

      Make sure that there are no short circuits to the auxiliary battery.


    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 2 COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)

  14. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY - NO. 2 INTEGRATION RELAY)


    1. Remove the FAN No. 1 relay, FAN No. 2 relay and FAN No. 3 relay from the engine room relay block and junction block assembly.

    2. Disconnect the 1B No. 2 integration relay connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (FAN No. 1 relay) - 1B-4 Always Below 1 Ω
      1 (FAN No. 2 relay) - 1B-4 Always Below 1 Ω
      1 (FAN No. 3 relay) - 1B-4 Always Below 1 Ω
      1 (FAN No. 1 relay) or 1B-4 - Body ground Always 10 kΩ or higher
      1 (FAN No. 2 relay) or 1B-4 - Body ground Always 10 kΩ or higher
      1 (FAN No. 3 relay) or 1B-4 - Body ground Always 10 kΩ or higher

    OK

    CHECK ECM POWER SOURCE CIRCUIT Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY - NO. 2 INTEGRATION RELAY)