COOLING FAN SYSTEM Cooling Fan Circuit

DESCRIPTION

The ECM turns on or off the fan relays 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 on or off the fan relays in order to control the speed of the cooling fan motors in two steps.

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 INTELLIGENT TESTER (CONTROL THE ELECTRIC COOLING FAN)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

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

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

    B

    INSPECT ECM (FANL AND FANH VOLTAGE) Click here

    C

    INSPECT FAN NO. 1 RELAY Click here

    A

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

  2. INSPECT ECM (FANL AND FANH VOLTAGE)


    1. A003RZJE50
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

    2. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A50-22 (FANH) - Body ground Power switch on (IG) 11 to 14 V
      A50-21 (FANL) - Body ground Power switch on (IG) 11 to 14 V

    4. Reconnect the ECM connector.


    NG

    CHECK FUSE (ECU-IG NO. 1 FUSE VOLTAGE) Click here

    OK

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


    1. A003U8QE01
      Text in Illustration
      *1 Engine Room Relay Block

      Remove the FAN NO. 1 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 NO. 1 relay) - Body ground Always 11 to 14 V

    3. Reinstall the FAN NO. 1 relay.


    NG

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

    OK

  4. INSPECT ENGINE ROOM RELAY BLOCK (FAN NO. 3 RELAY VOLTAGE)


    1. A003S03E01
      Text in Illustration
      *1 Engine Room Relay Block

      Remove the FAN NO. 3 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
      5 (FAN NO. 3 relay) - Body ground Always 11 to 14 V

    3. Reinstall the FAN NO. 3 relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - FAN NO. 3 RELAY)

    OK

  5. INSPECT FAN NO. 1 RELAY


    1. A003U7SE50

      Remove the FAN NO. 1 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 Battery voltage is not applied between terminals 1 and 2 10 kΩ or higher
      Battery voltage is applied between terminals 1 and 2 Below 1 Ω

    3. Reinstall the FAN NO. 1 relay.


    NG

    REPLACE FAN NO. 1 RELAY

    OK

  6. INSPECT FAN NO. 2 RELAY


    1. A003UIEE01

      Remove the FAN NO. 2 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 - 4 Battery voltage is not applied between terminals 1 and 2 Below 1 Ω
      Battery voltage is applied between terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage is not applied between terminals 1 and 2 10 kΩ or higher
      Battery voltage is applied between terminals 1 and 2 Below 1 Ω

    3. Reinstall the FAN NO. 2 relay.


    NG

    REPLACE FAN NO. 2 RELAY

    OK

  7. INSPECT FAN NO. 3 RELAY


    1. A003U7SE50

      Remove the FAN NO. 3 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 Battery voltage is not applied between terminals 1 and 2 10 kΩ or higher
      Battery voltage is applied between terminals 1 and 2 Below 1 Ω

    3. Reinstall the FAN NO. 3 relay.


    NG

    REPLACE FAN NO. 3 RELAY

    OK

  8. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - BODY GROUND)


    1. Remove the FAN NO. 2 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
      5 (FAN NO. 2 relay) - Body ground Always Below 1 Ω

    3. Reinstall the FAN NO. 2 relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM RELAY BLOCK - 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 cooling fan motor connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A58-1 - Body ground Always Below 1 Ω

    3. Reconnect the cooling fan motor connector.


    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)


    1. Disconnect the cooling fan motor connector.

    2. Remove the FAN NO. 1 relay and FAN NO. 2 relay from the 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
      A58-2 - 5 (FAN NO. 1 relay) Always Below 1 Ω
      A58-2 - 4 (FAN NO. 2 relay) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A58-2 or 5 (FAN NO. 1 relay) - Body ground Always 10 kΩ or higher
      A58-2 or 4 (FAN NO. 2 relay) - Body ground Always 10 kΩ or higher

    4. Reconnect the cooling fan motor connector.

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


    NG

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

    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)


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

    2. Remove the FAN NO. 2 relay and FAN NO. 3 relay from the 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
      A59-1 - 3 (FAN NO. 2 relay) Always Below 1 Ω
      A59-2 - 3 (FAN NO. 3 relay) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A59-1 or 3 (FAN NO. 2 relay) - Body ground Always 10 kΩ or higher
      A59-2 or 3 (FAN NO. 3 relay) - Body ground Always 10 kΩ or higher

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

    5. Reinstall the FAN NO. 2 relay and FAN NO. 3 relay.


    NG

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

    OK

  14. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY - FAN NO. 2 RELAY)


    1. Remove the FAN NO. 1 relay and FAN NO. 2 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
      1 (FAN NO. 1 relay) - 1 (FAN NO. 2 relay) Always Below 1 Ω
      2 (FAN NO. 1 relay) - 2 (FAN NO. 2 relay) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      1 (FAN NO. 1 relay) or 1 (FAN NO. 2 relay) - Body ground Always 10 kΩ or higher
      2 (FAN NO. 1 relay) or 2 (FAN NO. 2 relay) - Body ground Always 10 kΩ or higher

    3. Reinstall the FAN NO. 1 relay and FAN NO. 2 relay.


    NG

    REPLACE ENGINE ROOM RELAY BLOCK

    OK

    REPLACE ECM Click here

  15. CHECK FUSE (ECU-IG NO. 1 FUSE VOLTAGE)


    1. A003T3JE02
      Text in Illustration
      *1 Instrument Panel Junction Block Assembly

      Remove the ECU-IG NO. 1 fuse from the instrument panel 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 Switch Condition Specified Condition
      1 (ECU-IG NO. 1 fuse) - Body ground Power switch on (IG) 11 to 14 V

    4. Reinstall the ECU-IG NO. 1 fuse.


    NG

    INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (IG1 NO. 1 RELAY) Click here

    OK

  16. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. Disconnect the instrument panel junction block assembly connector.

      A003TNOE02

    2. Remove the ECU-IG NO. 1 fuse from the instrument panel junction block assembly.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      2C-30 - 2 (ECU-IG NO. 1) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      2C-30 or 2 (ECU-IG NO. 1) - Body ground Always 10 kΩ or higher
      Text in Illustration
      *1 Instrument Panel Junction Block Assembly *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

    4. Reconnect the ECU-IG NO. 1 fuse.

    5. Reconnect the instrument panel junction block assembly connector.


    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

    OK

  17. INSPECT FAN NO. 1 RELAY


    1. A003U7SE50

      Remove the FAN NO. 1 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 Battery voltage is not applied between terminals 1 and 2 10 kΩ or higher
      Battery voltage is applied between terminals 1 and 2 Below 1 Ω

    3. Reinstall the FAN NO. 1 relay.


    NG

    REPLACE FAN NO. 1 RELAY

    OK

  18. INSPECT FAN NO. 2 RELAY


    1. A003UIEE01

      Remove the FAN NO. 2 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 - 4 Battery voltage is not applied between terminals 1 and 2 Below 1 Ω
      Battery voltage is applied between terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage is not applied between terminals 1 and 2 10 kΩ or higher
      Battery voltage is applied between terminals 1 and 2 Below 1 Ω

    3. Reinstall the FAN NO. 2 relay.


    NG

    REPLACE FAN NO. 2 RELAY

    OK

  19. INSPECT FAN NO. 3 RELAY


    1. A003U7SE50

      Remove the FAN NO. 3 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 Battery voltage is not applied between terminals 1 and 2 10 kΩ or higher
      Battery voltage is applied between terminals 1 and 2 Below 1 Ω

    3. Reinstall the FAN NO. 3 relay.


    NG

    REPLACE FAN NO. 3 RELAY

    OK

  20. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - ECM)


    1. Remove the FAN NO. 1 relay, FAN NO. 2 relay and FAN NO. 3 relay from the engine room 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
      2 (FAN NO. 1 relay) - A50-22 (FANH) Always Below 1 Ω
      2 (FAN NO. 2 relay) - A50-22 (FANH) Always Below 1 Ω
      2 (FAN NO. 3 relay) - A50-21 (FANL) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      2 (FAN NO. 1 relay) or A50-22 (FANH) - Body ground Always 10 kΩ or higher
      2 (FAN NO. 2 relay) or A50-22 (FANH) - Body ground Always 10 kΩ or higher
      2 (FAN NO. 3 relay) or A50-21 (FANL) - Body ground Always 10 kΩ or higher

    4. Reinstall the FAN NO. 1 relay, FAN NO. 2 relay and FAN NO. 3 relay.

    5. Reconnect the ECM connector.


    NG

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

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK - ENGINE ROOM RELAY BLOCK)

  21. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (IG1 NO. 1 RELAY)


    1. Disconnect the instrument panel junction block assembly connectors.

      A003URWE02

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2E-1 (for LHD) - 2C-30 Battery voltage is not applied between terminals 2B-25 - 2B-6 10 kΩ or higher
      Battery voltage is applied between terminals 2B-25 - 2B-6 Below 1 Ω
      2F-1 (for RHD) - 2C-30 Battery voltage is not applied between terminals 2B-25 - 2B-6 10 kΩ or higher
      Battery voltage is applied between terminals 2B-25 - 2B-6 Below 1 Ω
      Text in Illustration
      *A for LHD *B for RHD
      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      		 - -

    3. Reconnect the instrument panel junction block assembly connectors.


    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (IG1 NO. 1 RELAY)

    OK

  22. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (IG1 NO. 1 RELAY VOLTAGE)


    1. A003RZ6E01
      Text in Illustration
      *A for LHD
      *B for RHD
      *1 Instrument Panel Junction Block Assembly
      *a

      Front view of wire harness connector

      (to Instrument Panel Junction Block Assembly)

      Disconnect the instrument panel junction block assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      2E-1 (for LHD) - Body ground Always 11 to 14 V
      2F-1 (for RHD) - Body ground Always 11 to 14 V

    3. Reconnect the instrument panel junction block assembly connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    OK

  23. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BODY GROUND)


    1. Disconnect the instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2B-6 - Body ground Always Below 1 Ω

    3. Reconnect the instrument panel junction block assembly connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BODY GROUND)

    OK

  24. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL J/B ASSEMBLY - POWER MANAGEMENT CONTROL ECU)


    1. Disconnect the instrument panel junction block assembly connector.

    2. Disconnect the power management control 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
      E112-2 (IG1D) - 2B-25 Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      E112-2 (IG1D) or 2B-25 - Body ground Always 10 kΩ or higher

    4. Reconnect the instrument panel junction block assembly connector.

    5. Reconnect the power management control ECU connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INSTRUMENT PANEL J/B ASSEMBLY - POWER MANAGEMENT CONTROL ECU)

    OK

    CHECK ENTRY AND START SYSTEM Click here

  25. INSPECT FAN NO. 1 RELAY


    1. A003U7SE50

      Remove the FAN NO. 1 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 Battery voltage is not applied between terminals 1 and 2 10 kΩ or higher
      Battery voltage is applied between terminals 1 and 2 Below 1 Ω

    3. Reinstall the FAN NO. 1 relay.


    NG

    REPLACE FAN NO. 1 RELAY

    OK

  26. INSPECT FAN NO. 3 RELAY


    1. A003U7SE50

      Remove the FAN NO. 3 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 Battery voltage is not applied between terminals 1 and 2 10 kΩ or higher
      Battery voltage is applied between terminals 1 and 2 Below 1 Ω

    3. Reinstall the FAN NO. 3 relay.


    NG

    REPLACE FAN NO. 3 RELAY

    OK

  27. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - ECM)


    1. Remove the FAN NO. 1 relay, FAN NO. 2 relay and FAN NO. 3 relay from the engine room relay block.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      2 (FAN NO. 1 relay) or 2 (FAN NO. 2 relay) or A50-22 (FANH) - Body ground Always 10 kΩ or higher
      2 (FAN NO. 3 relay) or A50-21 (FANL) - Body ground Always 10 kΩ or higher

    4. Reinstall the FAN NO. 1 relay, FAN NO. 2 relay and FAN NO. 3 relay.

    5. Reconnect the ECM connector.


    NG

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

    OK

    REPLACE ECM Click here