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 76°C (169°F).

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

      4. w/ Air Conditioning System:

        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 76°C (169°F), and that the A/C switch is off (w/ Air Conditioning System).

    4. w/ Air Conditioning System:

      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).

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

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

      A003ETIE03

      Tech Tips

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

      Tech Tips


      • This system can also be checked using the GTS.

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

  2. INSPECT NO. 1 COOLING FAN MOTOR

    Tech Tips

    Terminals of ECM Click here


    1. A003CSAE01

      Check the input voltage.


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

      2. Turn the ignition switch to ON.

        Measure the voltage at the +B1 terminal of the disconnected harness side connector.

        Standard voltage
        11 to 14 V

      3. 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. Measure the resistance between ECM terminal RFC and cooling fan motor terminal SI.

        Standard resistance
        Below 1 Ω

        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 76°C (169°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

        (40 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 (w/ Air Conditioning System)

    Tech Tips

    Terminals of ECM Click here


    1. A003CSAE02

      Check the input voltage.


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

      2. Turn the ignition switch to ON.

        Measure the voltage at the +B2 terminal of the disconnected harness side connector.

        Standard voltage
        11 to 14 V

      3. 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. Measure the resistance between ECM terminal RFC2 and cooling fan motor terminal SI2.

        Standard resistance
        Below 1 Ω

        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 76°C (169°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 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.