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. By basing its control on the operating conditions, the ECM can control the fan speed optimally using the cooling fan ECU, achieving both high cooling performance and quietness.

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.

PROCEDURE


  1. PERFORM ACTIVE TEST USING GTS (CONTROL THE ELECTRIC COOLING FAN)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    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 fan while operating it using the GTS.


      Powertrain > Engine and ECT > Active Test
      Tester Display
      Control the Electric Cooling Fan
      OK
      Tester 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

    A

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

    C

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

    B

  2. 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

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. Disconnect the A41 cooling fan ECU connector.

    2. Turn the ignition switch to ON.

    3. A01TAKXC03
      *a

      Front view of wire harness connector

      (to Cooling fan ECU)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A41-1 (+B1) - A41-3 (E1) Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

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


    1. Disconnect the A50 ECM connector.

    2. Disconnect the A41 cooling fan ECU connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A50-45 (RFC) or A41-2 (SI) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

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

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


    1. Disconnect the A41 cooling fan ECU connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A41-3 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  6. INSPECT FAN NO. 1 RELAY


    1. Inspect the FAN NO. 1 relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FAN NO. 1 RELAY

    OK

  7. INSPECT ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY (FAN NO. 1 RELAY)


    1. A01TBPKC01
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 FAN NO. 1 Relay

      Remove the FAN NO. 1 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 Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

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


    1. Disconnect the A41 cooling fan ECU connector.

    2. Remove the FAN NO. 1 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 (Check for Open)
      Tester Connection Condition Specified Condition
      A41-1 (+B1) - 5 (FAN NO. 1 relay) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A41-1 (+B1) or 5 (FAN NO. 1 relay) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    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 engine room relay block and junction block assembly.

    2. 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) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  10. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)


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

    2. Disconnect the 3A instrument panel junction block assembly connector.

    3. 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) - 3A-37 Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      1 (FAN NO. 1 relay) or 3A-37 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    OK

  11. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. Disconnect the 3A, 3B, 3C and 3D instrument panel junction block assembly connectors.

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

      A01TBKVC01
      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      3B-1 - 3A-37 Battery voltage is applied between terminals 3D-24 and 3C-9 Below 1 Ω
      3B-1 - 3A-37 Battery voltage is not applied between terminals 3D-24 and 3C-9 10 kΩ or higher
      3B-1 - 3D-48 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

    OK

  12. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY POWER SOURCE)


    1. Disconnect the 3B instrument panel junction block assembly connector.

    2. A01T94CC05
      *a

      Front view of wire harness connector

      (to Instrument Panel Junction Block Assembly)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3B-1 - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

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


    1. Disconnect the 3C instrument panel junction block assembly connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      3C-9 - Body ground Always Below 1 Ω
      Result
      Result Proceed to
      OK (w/o entry and start system) A
      OK (w/ entry and start system) B
      NG C

    B

    CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)) Click here

    C

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

    A

  14. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - IGNITION OR STARTER SWITCH ASSEMBLY)


    1. Disconnect the 3D instrument panel junction block assembly connector.

    2. Disconnect the E4 ignition or starter switch assembly connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      3D-24 - E4-8 (IG1) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      3D-24 or E4-8 (IG1) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - IGNITION OR STARTER SWITCH ASSEMBLY)

    OK

  15. INSPECT IGNITION OR STARTER SWITCH ASSEMBLY


    1. Inspect the ignition or starter switch assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION OR STARTER SWITCH ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    NG

    REPLACE IGNITION OR STARTER SWITCH ASSEMBLY Click here

  16. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))


    1. Disconnect the 3D instrument panel junction block assembly connector.

    2. Disconnect the E35 certification ECU (smart key ECU assembly) connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      3D-24 - E35-6 (IG1D) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      3D-24 or E35-6 (IG1D) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    GO TO ENTRY AND START SYSTEM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))

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


    1. Disconnect the A50 ECM connector.

    2. Disconnect the A41 cooling fan 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
      A50-45 (RFC) - A41-2 (SI) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

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


    1. Disconnect the z5 cooling fan motor connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      z5-1 (-) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

    REPLACE COOLING FAN MOTOR Click here