COOLING FAN SYSTEM ON-VEHICLE INSPECTION


  1. INSPECT COOLING FAN SYSTEM


    1. Put the vehicle in the following state:


      1. The ignition switch is off.

      2. The coolant temperature is less than 74°C (165°F).

      3. The battery voltage is between 11 and 14 V.

      4. The A/C switch is off.

    2. Turn the ignition switch to ON (engine off) and wait for approximately 10 seconds. Check that the fans do not operate.

    3. Start the engine. Check that the fans do not operate with the engine idling.

      Tech Tips


      • Make sure that the radiator coolant temperature is less than 74°C (165°F), and that the A/C switch is off.

      Check that the fans operate when the A/C switch is turned on (The temperature is set to MAX COOL and the magnet clutch is operating).

    4. Check that the fans operate when the coolant sensor connector is disconnected.

    5. After the engine has warmed up, the fan operates as shown in the illustration.


      1. A003G2NE02
        A003AMHE02

        Tech Tips


        • No. 1 cooling fan motor:

          The coolant temperature at which the fans start to operate is approximately 76°C (169°F).

        • No. 2 cooling fan motor:

          The coolant temperature at which the fans start to operate is approximately 77°C (171°F).

        • This system can also be checked using the GTS.

        • Enter the following menus: Powertrain / Engine and ECT / Data List / Initial Engine Coolant Temp.

  2. INSPECT NO. 1 COOLING FAN MOTOR

    Tech Tips

    Terminals of ECM

    Click here


    1. Check the input voltage.


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

      2. Turn the ignition switch to ON.

      3. A003CSAE05
        Text in Illustration
        *a

        Front view of wire harness

        (to No. 1 Cooling Fan connector)

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

        Standard Voltage
        Tester Connection Switch Condition Specified Condition
        B90-3 (+B1) - Body ground Ignition switch ON 11 to 14 V

      4. If the terminal voltage is not within the specification, inspect the power source system (fusible link, fuse, wire harness and relay).

    2. Inspect the wire harness.


      1. Disconnect the ECM and No. 1 cooling fan motor connectors.

      2. A003CSAE11
        Text in Illustration
        *a

        Front view of wire harness

        (to No. 1 Cooling Fan connector)

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

        Standard Resistance
        Tester Connection Specified Condition
        B97-60 (RFC) - B90-2 (SI) Below 1Ω

        Tech Tips

        If the fan does not operate, there may be a short circuit. If the fan remains operating, there may be an open circuit.

      3. Inspect the ECM power source circuit and ground circuit.

    3. Inspect the input signal.

      Note


      • Be sure to perform the inspection with the radiator coolant temperature less than 74°C (165°F).


      1. Set the oscilloscope.

      2. A003DVOE02

        Using the oscilloscope, check the waveform between No. 1 cooling fan motor terminals E1 and SI.

        Standard
        Condition Input Signal

        Engine stopped

        IG switch ON

        Waveform 1

        (Duty ratio 0%)

        Engine idling

        A/C OFF

        Waveform 1

        (0%)

        Engine idling

        A/C ON

        Waveform 2

        (45 to 70%)
        Engine idling and ECT sensor connector disconnected

        Waveform 3

        (70%)

        Tech Tips

        If the input signal is abnormal, there is a malfunction in the ECM or cooling fan motor.

  3. INSPECT NO. 2 COOLING FAN MOTOR

    Tech Tips

    Terminals of ECM

    Click here


    1. Check the input voltage.


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

      2. Turn the ignition switch to ON.

      3. A003CSAE09
        Text in Illustration
        *a

        Front view of wire harness

        (to No. 2 Cooling Fan connector)

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

        Standard Voltage
        Tester Connection Switch Condition Specified Condition
        B91-3 (+B2) - Body ground Ignition switch ON 11 to 14 V

      4. If the terminal voltage is not within the specification, inspect the power source system (fusible link, fuse, wire harness and relay).

    2. Inspect the wire harness.


      1. Disconnect the ECM and No. 2 cooling fan motor connectors.

      2. A003CSAE10
        Text in Illustration
        *a

        Front view of wire harness

        (to No. 2 Cooling Fan connector)

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

        Standard Resistance
        Tester Connection Specified Condition
        B97-58 (RFC2) - B91-2 (SI2) Below 1Ω

        Tech Tips

        If the fan does not operate, there may be a short circuit. If the fan remains operating, there may be an open circuit.

      3. Inspect the ECM power source circuit and ground circuit.

    3. Inspect the input signal.

      Note


      • Be sure to perform the inspection with the radiator coolant temperature less than 74°C (165°F).


      1. Set the oscilloscope.

      2. A003DVOE02

        Using the oscilloscope, check the waveform between No. 2 cooling fan motor terminals E2 and SI2.

        Standard
        Condition Input Signal

        Engine stopped

        IG switch ON

        Waveform 1

        (Duty ratio 0%)

        Engine idling

        A/C OFF

        Waveform 1

        (0%)

        Engine idling

        A/C ON

        Waveform 2

        (40 to 60%)
        Engine idling and ECT sensor connector disconnected

        Waveform 3

        (70%)

        Tech Tips

        If the input signal is abnormal, there is a malfunction in the ECM or cooling fan motor.