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 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 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.


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

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

      OK
      Tester Operation Fan Operation
      ON Cooling fans operate
      OFF Cooling fans stop
      Result
      Result
      OK
      NG

    OK

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

    NG

  2. CHECK HARNESS AND CONNECTOR (FANH AND FANL VOLTAGE)


    1. Disconnect the A142 ECM connector.

    2. Turn the power switch on (IG).

    3. A00YOQTC06
      *a

      Front view of wire harness connector

      (to ECM)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A142-8 (FANH) - Body ground Power switch on (IG) 11 to 14 V
      A142-7 (FANL) - Body ground Power switch on (IG) 11 to 14 V

    4. Reconnect the A142 ECM connector.

      Result
      Result
      OK
      NG

    NG

    INSPECT FAN NO. 1 RELAY Click here

    OK

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


    1. A00YNW1C01
      *1 No. 1 Engine Room Relay Block and No. 1 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 No. 1 engine room relay block and No. 1 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
      3 (FAN NO. 3 relay) - Body ground Always 11 to 14 V

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

      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT FAN NO. 1 RELAY


    1. Inspect the FAN NO. 1 relay.

      Click here

      Result
      Result
      OK
      NG

    NG

    REPLACE FAN NO. 1 RELAY

    OK

  5. INSPECT FAN NO. 2 RELAY


    1. Inspect the FAN NO. 2 relay.

      Click here

      Result
      Result
      OK
      NG

    NG

    REPLACE FAN NO. 2 RELAY

    OK

  6. INSPECT FAN NO. 3 RELAY


    1. Inspect the FAN NO. 3 relay.

      Click here

      Result
      Result
      OK
      NG

    NG

    REPLACE FAN NO. 3 RELAY

    OK

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


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

    3. Reinstall the FAN NO. 2 relay.

      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. INSPECT COOLING FAN MOTOR


    1. Inspect the cooling fan motor.

      Result
      Result
      OK
      NG

    NG

    REPLACE COOLING FAN MOTOR

    OK

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


    1. Disconnect the A112 cooling fan motor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A112-1 - Body ground Always Below 1 Ω

    3. Reconnect the A112 cooling fan motor connector.

      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR - NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY)


    1. Disconnect the A112 cooling fan motor connector.

    2. Remove the FAN NO. 1 relay and FAN NO. 2 relay from the No. 1 engine room relay block and No. 1 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
      A112-2 - 5 (FAN NO. 1 relay) Always Below 1 Ω
      A112-2 - 4 (FAN NO. 2 relay) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A112-2 or 5 (FAN NO. 1 relay) - Body ground Always 10 kΩ or higher
      A112-2 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.

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

    5. Reconnect the A112 cooling fan motor connector.

      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  11. INSPECT NO. 2 COOLING FAN MOTOR


    1. Inspect the No. 2 cooling fan motor.

      Result
      Result
      OK
      NG

    NG

    REPLACE NO. 2 COOLING FAN MOTOR

    OK

  12. CHECK HARNESS AND CONNECTOR (NO. 2 COOLING FAN MOTOR - NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY)


    1. Disconnect the A113 No. 2 cooling fan motor connector.

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

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

      Tech Tips

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A113-1 - 3 (FAN NO. 2 relay) Always Below 1 Ω
      A113-2 - 5 (FAN NO. 3 relay) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A113-1 or 3 (FAN NO. 2 relay) - Body ground Always 10 kΩ or higher
      A113-2 or 5 (FAN NO. 3 relay) - Body ground Always 10 kΩ or higher

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

    5. Reconnect the A113 No. 2 cooling fan motor connector.

      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  13. 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 No. 1 engine room relay block and No. 1 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
      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

      Tech Tips

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

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

      Result
      Result
      OK
      NG

    OK

    REPLACE ECM

    NG

    REPLACE NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY

  14. INSPECT FAN NO. 1 RELAY


    1. Inspect the FAN NO. 1 relay.

      Click here

      Result
      Result
      OK
      NG

    NG

    REPLACE FAN NO. 1 RELAY

    OK

  15. INSPECT FAN NO. 2 RELAY


    1. Inspect the FAN NO. 2 relay.

      Click here

      Result
      Result
      OK
      NG

    NG

    REPLACE FAN NO. 2 RELAY

    OK

  16. INSPECT FAN NO. 3 RELAY


    1. Inspect the FAN NO. 3 relay.

      Click here

      Result
      Result
      OK
      NG

    NG

    REPLACE FAN NO. 3 RELAY

    OK

  17. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - ECM)


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

    2. Disconnect the A142 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) - A142-8 (FANH) Always Below 1 Ω
      2 (FAN NO. 2 relay) - A142-8 (FANH) Always Below 1 Ω
      2 (FAN NO. 3 relay) - A142-7 (FANL) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      2 (FAN NO. 1 relay) or A142-8 (FANH) - Body ground Always 10 kΩ or higher
      2 (FAN NO. 2 relay) or A142-8 (FANH) - Body ground Always 10 kΩ or higher
      2 (FAN NO. 3 relay) or A142-7 (FANL) - Body ground Always 10 kΩ or higher

      Tech Tips

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

    4. Reconnect the A142 ECM connector.

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

      Result
      Result
      OK
      NG

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - ECM)