GRILLE SHUTTER SYSTEM DETAILS


  1. FUNCTION OF MAIN COMPONENTS


    1. The grille shutter system comprises the following parts and functions:

      Component Function
      Skid Control ECU Assembly Outputs the vehicle speed signal to the air conditioning amplifier assembly.
      Front Speed Sensor RH Outputs the wheel speed signal to the skid control ECU assembly.
      Front Speed Sensor LH
      Rear Speed Sensor RH
      Rear Speed Sensor LH
      Grille Shutter (Radiator Shutter Sub-assembly) Opens and closes at the lower grille portion in accordance with vehicle conditions.
      Swing Grille Actuator Assembly

      • Incorporates the grille shutter ECU and operates the grille shutter in accordance with vehicle conditions.

      • Outputs a failure signal during a system malfunction.
      Thermistor Assembly Outputs an outer temperature signal to the air conditioning amplifier assembly.
      Air Conditioning Pressure Sensor Outputs a refrigerant pressure signal to the air conditioning amplifier assembly.
      ECM Outputs an engine coolant temperature signal to the air conditioning amplifier assembly.
      Engine Coolant Temperature Sensor Detects the temperature of the engine coolant and outputs the information to the ECM.
      Air Conditioning Amplifier Assembly

      • Outputs the vehicle information input from each sensor and from each ECU through CAN communication to the grille shutter ECU through LIN communication.

      • Relays a failure signal from the grille shutter ECU and sends the signal to the combination meter assembly.
      Combination Meter Assembly Displays a caution on the multi-information display when a failure signal is input from the air conditioning amplifier assembly.

  2. SYSTEM CONTROL


    1. This system has the following functions:

      Function Outline
      Closing Operation Closes the grille shutter for both quick warm-up and air resistance reduction when the grille shutter closing conditions are met.
      Opening Operation Opens the grille shutter to ensure cooling performance when the grille shutter opening conditions are met.
      Operation while Power Switch Off Opens the grille shutter approx. 5 seconds after the power switch is turned off while the grille shutter is closed.
      Operation when Malfunction Occurs Operates the grille shutter in accordance with the conditions when the occurrence of a malfunction is detected in the shutter.
      Actuator Protection Operation Stops the operation of the grille shutter to protect the swing grille actuator assembly when an operation malfunction is detected in the shutter.

    2. Closing Operation


      1. While the engine coolant temperature is less than 30.5°C (86.9°F), the grille shutter ECU closes the grille shutter when it judges that doing so will be beneficial for fuel efficiency when compared to the potential deterioration in fuel efficiency that is caused when the air conditioning is turned on or off.

      2. While the engine coolant temperature is between 30.5°C (86.9°F) and 92°C (197.6°F) and the driving speed is approximately between 80 km/h (50 mph) and 141 km/h (87 mph), the grille shutter ECU closes the grille shutter when it judges that doing so will be beneficial for fuel efficiency when compared to the potential deterioration in fuel efficiency that is caused when the air conditioning is turned on or off.

    3. Opening Operation


      1. While the outside temperature is 35°C (95°F) or less, the engine coolant temperature is 80°C (176.0°F) or more and the driving speed is less than approximately 80 km/h (50 mph), or while the engine coolant temperature is 80°C (176.0°F) or more and the driving speed is approximately 141 km/h (87 mph) or more, or when the grille shutter ECU judges that doing so will be beneficial for fuel efficiency when compared to the potential deterioration in fuel efficiency that is caused when the air conditioning is turned on, the grille shutter ECU opens the grille shutter.

      2. While the engine coolant temperature is 94°C (201.2°F) or more, or the engine coolant temperature is 30.5°C (86.9°F) or more and the driving speed is less than approximately 80 km/h (50 mph), or while the engine coolant temperature is 30.5°C (86.9°F) or more and the driving speed is approximately 141 km/h (87 mph) or more, or when the outer temperature has become greater than 35°C (95.0°F), or when the grille shutter ECU judges that doing so will be beneficial for fuel efficiency when compared to the potential deterioration in fuel efficiency that is caused when the air conditioning is turned on, the grille shutter ECU opens the grille shutter.

    4. Operation when Malfunction Occurs


      1. The grille shutter ECU operates the grille shutter in accordance with each condition when the following malfunctions occur in the shutter:


        • When the grille shutter ECU detects that the grille shutter is stuck, it opens the shutter.

        • When a malfunction has been detected between the time the power switch was turned on (IG) to the time it was turned off, or when the grille sensor has not been operated even once, the grille shutter ECU closes and then opens the grille shutter.

        • When the engine coolant temperature increases abnormally, the grille shutter ECU closes and then opens the grille shutter.

    5. Actuator Protection Operation


      1. When the following conditions occur while the grille shutter is operating, the grille shutter ECU stops grille shutter operation in accordance with each condition, thus protecting the actuator:


        • The grille shutter ECU stops grille shutter operation if the radiator shutter does not rotate even though a certain time has elapsed.

        • The grille shutter ECU stops grille shutter operation if it detects that the radiator shutter has rotated enough to make the grille shutter open and closed.

        • The grille shutter ECU stops grille shutter operation if it cannot detect a sufficient amount of rotation to make the shutter open and closed even though a certain amount of time has elapsed.

  3. CONSTRUCTION


    1. The grille shutter (radiator shutter sub-assembly) consists of 4 shutters to open and close the lower grille portion, a swing grille actuator assembly to drive the shutter, a frame and others.

    2. The grille shutter ECU, motor, pulse sensor and gear are installed in the swing grille actuator assembly.

      A01FPNWE01
      Text in Illustration
      *1 Shutter *2 Swing Grille Actuator Assembly
      *3 Frame *4 Motor
      *5 Gear *6 Pulse Sensor
      *7 Grille Shutter ECU - -
      *a Swing Grill Actuator Assembly Cross-section - -

  4. FAIL-SAFE


    1. The grille shutter ECU or the air conditioning amplifier assembly detects the following malfunctions, performs fail-safe, sends a failure signal to the combination meter assembly and displays "Grille Shutter Inoperable" on the multi-information display.

      Trouble Area Condition
      Grille Shutter Malfunction

      When the grille shutter enters the following states, the motor is stopped and caution message is displayed:


      • The motor does not stop even after a certain time has elapsed since the grille shutter started operating.

      • The grille shutter does not operate.

      • There is only a small amount of grille shutter rotation.
      Motor Malfunction

      When the grille shutter enters the following state, the motor is stopped and caution message is displayed:


      • The grille shutter does not operate.
      Pulse Sensor Malfunction

      When the grille shutter enters the following state, the motor is stopped and caution message is displayed:


      • Motor rotation cannot be detected.
      LIN Communication Malfunction

      When the grille shutter enters the following state, operation is performed only while the power switch is off and a warning message is displayed:


      • The air conditioning amplifier assembly cannot communicate with the grille shutter ECU.
      Power Source Malfunction

      When the grille shutter enters the following state, caution message is displayed:


      • The air conditioning amplifier assembly detects an abnormal voltage in the grille shutter power source.