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 the 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. The cooling fan speed is determined based on engine coolant temperature, air conditioner operating conditions, engine speed, and vehicle speed.

INSPECTION PROCEDURE

PROCEDURE


  1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE COOLING FAN)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch on (IG).

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

    4. Check the operation of the cooling fan while operating it using the intelligent tester.

      OK
      The cooling fan rotates.

    NG

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

    OK

    REPLACE ECM Click here

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


    1. Disconnect the D31 connector from the ECM.

      A017F4EE02

    2. Disconnect the cooling fan ECU connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      D31-14 (RFC) - A9-2 (SI) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT NO. 1 COOLING FAN MOTOR


    1. A017G4XE01

      Disconnect the No. 1 cooling fan motor connector.

    2. Connect the battery positive terminal to terminal 2 of the cooling fan connector, and connect the battery negative terminal to terminal 1 of the No. 1 cooling fan motor connector.

      OK
      The No. 1 cooling fan rotates.

    NG

    REPLACE NO. 1 COOLING FAN MOTOR Click here

    OK

  4. INSPECT NO. 2 COOLING FAN MOTOR


    1. A017GA3E01

      Disconnect the No. 2 cooling fan motor connector.

    2. Connect the battery positive terminal to terminal 2 of the cooling fan connector, and connect the battery negative terminal to terminal 1 of the No. 2 cooling fan motor connector.

      OK
      The No. 2 cooling fan rotates.

    NG

    REPLACE NO. 2 COOLING FAN MOTOR Click here

    OK

  5. CHECK COOLING FAN ECU (POWER SOURCE)


    1. A017CQIE03

      Disconnect the cooling fan ECU connector.

    2. Turn the ignition switch on (IG).

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      A9-3 (+B1) - A9-1 (E1) Ignition switch on (IG) 11 to 14 V

    NG

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

    OK

    REPLACE COOLING FAN ECU Click here

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


    1. A017CQIE04

      Disconnect the cooling fan ECU connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      A9-1 (E1) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. INSPECT FAN MAIN RELAY


    1. A017CIR

      Remove the FAN MAIN relay from the engine room relay block and junction 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
      3 - 5 Apply battery voltage between terminals 1 and 2 Below 1 Ω

    NG

    REPLACE FAN MAIN RELAY

    OK

  8. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - FAN MAIN RELAY)


    1. A017D5KE02

      Disconnect the cooling fan ECU connector.

    2. Remove the FAN MAIN relay from the engine room relay block and junction block.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      A9-3 (+B1) - 5 (FAN MAIN relay) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (FAN MAIN RELAY - BODY GROUND)


    1. A017ENWE02

      Remove the FAN MAIN relay from the engine room relay block and junction block.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      2 (FAN MAIN relay) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK HARNESS AND CONNECTOR (FAN MAIN RELAY - FAN MAIN FUSE)


    1. A017CGAE02

      Remove the FAN MAIN relay from the engine room relay block and junction block.

    2. Remove the fusible link block assembly from the engine room relay block and junction block.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      3 (FAN MAIN relay) - 1 (FAN MAIN fuse) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  11. INSPECT FUSIBLE LINK BLOCK ASSEMBLY (FAN MAIN FUSE)


    1. A017C5IE05

      Remove the fusible link block assembly from the engine room relay block and junction block.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      1 - 2 (FAN MAIN fuse) Always Below 1 Ω

    NG

    REPLACE FUSIBLE LINK BLOCK ASSEMBLY

    OK

  12. CHECK FUSE (EFI MAIN)


    1. A017EOCE01

      Remove the EFI MAIN fuse from the engine room relay block and junction block.


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

        Standard resistance
        Tester Connection Condition Specified Condition
        EFI MAIN fuse Always Below 1 Ω

    NG

    REPLACE FUSE

    OK

  13. CHECK HARNESS AND CONNECTOR (EFI MAIN FUSE - ENGINE ROOM JUNCTION BLOCK ASSEMBLY)


    1. Remove the EFI MAIN fuse from the engine room relay block and junction block.

    2. A017D9S

      Remove the engine room junction block assembly from the engine room relay block and junction block.

    3. A017G6BE01

      Disconnect the 2E connector from the engine room junction block assembly.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      2 (EFI MAIN fuse) - 2E-12 Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  14. CHECK HARNESS AND CONNECTOR (FAN MAIN RELAY - ENGINE ROOM JUNCTION BLOCK ASSEMBLY)


    1. Remove the FAN MAIN relay from the engine room relay block and junction block.

    2. A017D9S

      Remove the engine room junction block assembly from the engine room relay block and junction block.

    3. A017EL1E02

      Disconnect the 2E connector from the engine room junction block assembly.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      1 (FAN MAIN reray) - 2E-7 Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  15. CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY - BODY GROUND)


    1. A017BEA

      Remove the engine room junction block assembly from the engine room relay block and junction block.

    2. A017CUOE01

      Disconnect the 2D and 2E connectors from the engine room junction block assembly.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      2D-8 - Body ground Always Below 1 Ω
      2E-10 - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the D31 connector from the ECM.

    2. A017D9S

      Remove the engine room junction block assembly from the engine room relay block and junction block.

    3. Disconnect the 2E connector from the engine room junction block assembly.

      A017G61E01

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

      Standard resistance
      Tester Connection Condition Specified Condition
      D31-8 (MREL) - 2E-9 Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  17. INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (EFI RELAY)


    1. A017C13

      Remove the engine room junction block assembly from the engine room relay block and junction block.

    2. A017B8HE01

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

      Standard resistance
      Tester Connection Condition Specified Condition
      2E-12 - 2E-7 Battery voltage is not applied between terminals 2E-9 and 2E-10 10 kΩ or higher
      2E-12 - 2E-7 Apply battery voltage between terminals 2E-9 and 2E-10 Below 1 Ω

      Note

      While using the battery for the inspection, do not bring the positive and negative tester probes too close to each other as a short circuit may occur.


    NG

    REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY Click here

    OK

    REPLACE ECM Click here