COOLING FAN SYSTEM Cooling Fan Circuit

DESCRIPTION

The ECM monitors engine coolant temperature, the air conditioning switch, the air conditioning refrigerant pressure and engine speed. It also sends the FANL and FANH signals to the engine room junction block assembly to operate the cooling fan motor and No. 2 cooling fan motor.

The ECM switches the cooling fan motor and No. 2 cooling fan motor circuits from a series (low speed rotation) to parallel (high speed rotation) connection by changing the FANH signal, thereby controlling the 2 levels of fan speed.

Input signal FANL OFF ON ON
FANH OFF OFF ON
Condition Cooling fan motor OFF ON (Series connection (Low speed rotation)) ON (Parallel connection (High speed rotation))
No. 2 cooling fan motor OFF ON (Series connection (Low speed rotation)) ON (Parallel connection (High speed rotation))
A01VZRIE01

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 inspection procedure.

PROCEDURE


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

    Tech Tips

    If cooling fan speed does not change, proceed to the next step.


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

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

    5. Check the operation of the cooling fans using the GTS.

      OK
      Tester Operation Fan Operation
      HIGH Cooling fans operates
      LOW Cooling fans operates
      OFF Cooling fans stops

    OK

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

    NG

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


    1. Disconnect the A75 ECM connector.

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

    3. Disconnect the engine room junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A75-17 (FANL) - 1F-17 (FANL) Always Below 1 Ω
      A75-4 (FANH) - 1F-9 (FANH) Always Below 1 Ω
      A75-17 (FANL) or 1F-17 (FANL) - Body ground Always 10 kΩ or higher
      A75-4 (FANH) or 1F-9 (FANH) - Body ground Always 10 kΩ or higher

    NG

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

    OK

  3. INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (SIGNAL READING CHECK)


    1. Using a voltmeter, check the signal reading of the engine room junction block assembly Click here.

      OK
      Output signal reading is normal.

    NG

    INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (RESULTS OF SIGNAL READING CHECK) Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY POWER SOURCE)


    1. A01VZ9PE05
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *a ALT
      *b BATT

      Remove the engine room junction block assembly 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
      (BATT) - Body ground Always 11 to 14 V
      (ALT) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY POWER SOURCE)

    OK

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


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

    2. Disconnect the 1F and 1G engine room junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1F-3 (GND1) - Body ground Always Below 1 Ω
      1G-4 (GND2) - Body ground Always Below 1 Ω

      Tech Tips

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


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY - BODY GROUND)

    OK

  6. CHECK HARNESS AND CONNECTOR (FAN RELAY POWER SOURCE)


    1. A01W5N9E02
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 FAN Relay

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

    2. Turn the engine 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 relay) - Body ground Engine switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN RELAY POWER SOURCE)

    OK

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


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

    2. Disconnect the 1F engine room junction block assembly connector.

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1F-15 (IGN) - 1 (FAN relay) Always Below 1 Ω
      1F-15 (IGN) or 1 (FAN relay) - Body ground Always 10 kΩ or higher

      Tech Tips

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


    NG

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

    OK

  8. INSPECT FAN RELAY


    1. Inspect the FAN relay Click here.


    NG

    REPLACE FAN RELAY

    OK

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


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

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

    3. Disconnect the 1F engine room junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (FAN relay) - 1F-8 (FN2S) Always Below 1 Ω
      2 (FAN relay) or 1F-8 (FN2S) - Body ground Always 10 kΩ or higher

      Tech Tips

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


    NG

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

    OK

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


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

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

    3. Disconnect the 1M engine room junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      4 (FAN relay) - 1M-2 (FAN2) Always Below 1 Ω
      4 (FAN relay) or 1M-2 (FAN2) - Body ground Always 10 kΩ or higher

      Tech Tips

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


    NG

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

    OK

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


    1. Remove the FAN 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 relay) - Body ground Always Below 1 Ω

      Tech Tips

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


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN RELAY - BODY GROUND)

    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 (FAN RELAY - NO. 2 COOLING FAN MOTOR)


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

    2. Disconnect the A8 No. 2 cooling fan motor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 (FAN relay) - A8-1 Always Below 1 Ω
      3 (FAN relay) or A8-1 - Body ground Always 10 kΩ or higher

      Tech Tips

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


    NG

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

    OK

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


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

    2. Disconnect the 1M engine room junction block assembly connector.

    3. Disconnect the A8 No. 2 cooling fan motor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A8-2 - 1M-3 (CFAN) Always Below 1 Ω
      A8-2 or 1M-3 (CFAN) - Body ground Always 10 kΩ or higher

      Tech Tips

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


    NG

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

    OK

  15. INSPECT COOLING FAN MOTOR


    1. Inspect the cooling fan motor Click here.


    NG

    REPLACE COOLING FAN MOTOR Click here

    OK

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


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

    2. Disconnect the 1M engine room junction block assembly connector.

    3. Disconnect the A7 cooling fan motor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1M-1 (RFAN) - A7-2 Always Below 1 Ω
      1M-1 (RFAN) or A7-2 - Body ground Always 10 kΩ or higher

      Tech Tips

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


    NG

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

    OK

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


    1. Disconnect the A7 cooling fan motor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A7-1 - Body ground Always Below 1 Ω

      Tech Tips

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


    OK

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

    NG

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