OCCUPANT CLASSIFICATION SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


    1. The main components in the occupant classification system have the following functions:

      Component Function
      Occupant Detection ECU The occupant detection ECU judges whether the front passenger seat is occupied based on signals from the 4 occupant detection sensors and the front seat inner belt assembly RH.
      Occupant Detection Sensor The output values of this sensor, which vary in accordance with the distortion that acts on the brackets, are output to the occupant detection ECU.
      Front Seat Inner Belt Assembly RH The front seat inner belt assembly RH detects whether or not the front passenger seat belt is fastened.
      Combination Meter Assembly SRS Airbag Warning Light The SRS airbag warning light turns on to alert the driver when the airbag sensor assembly detects a malfunction in the occupant classification system.
      Telltale Light Assembly AIRBAG ON Indicator Light The AIRBAG ON indicator light informs the driver whether the occupant detection ECU puts the instrument panel passenger airbag without door assembly and front seat outside belt assembly RH into an active state.
      AIRBAG OFF Indicator Light

      • The AIRBAG OFF indicator light informs the driver whether the occupant detection ECU puts the instrument panel passenger airbag without door assembly and front seat outside belt assembly RH into an inactive state.

      • If a malfunction occurs in the occupant classification system, the AIRBAG OFF indicator light comes on.
      Airbag Sensor Assembly If the airbag sensor assembly detects a malfunction in the occupant detection ECU, the airbag sensor assembly illuminates the SRS airbag warning light and AIRBAG OFF indicator light.

  2. OPERATING CONDITION


    1. The front passenger SRS components and AIRBAG ON/OFF indicator light operate as follows according to the occupant classification.

      Item Occupant Classification
      Adult Child Child Seat Unoccupied Malfunction
      SRS Front Passenger Airbag (Instrument Panel Passenger Airbag without Door Assembly) ○ - - - -
      SRS Front Side Airbag RH (Front Seat Airbag Assembly RH) ○ ○ ○ ○ ○
      Front Seat Outer Belt Assembly RH ○ ○ ○ - ○
      AIRBAG ON Indicator Light On Off Off Off Off
      AIRBAG OFF Indicator Light Off On On Off On
      SRS Airbag Warning Light Off Off Off Off On

      Tech Tips

      ○ : Enabled

      - : Disabled

  3. SYSTEM CONTROL


    1. In the occupant classification system, the occupant detection ECU calculates the weight of the occupant based on signals from the occupant detection sensors.

    2. This system recognizes the occupant as a child if it detects a weight of less than criteria value "B", and disables the SRS front passenger airbag (instrument panel passenger airbag without door assembly).

    3. The occupant detection ECU uses criteria value "A" to judge whether the seat is occupied by a child in accordance with the signals from the 4 occupant detection sensors and front seat inner belt assembly RH, and criteria value "B" to judge whether the occupant is an adult or child (with child seat).

    4. The occupant detection ECU judges that the seat is unoccupied when the judgment value is lower than criteria value "A" and the front seat inner belt assembly RH is off.

    5. If the ignition switch is turned to ON under the following conditions, the system performs an initial check. Then, the system prohibits the deployment of the SRS front passenger airbag (instrument panel passenger airbag without door assembly) and front seat outside belt assembly (pretensioner squib).

      A01T0IRE01

    6. If the judgment value is lower than criteria value "B" and the front seat inner belt assembly RH is on, the occupant detection ECU judges that a child seat is installed.

    7. If the judgment value is higher than criteria value "A", but lower than criteria value "B", and the front seat inner belt assembly RH is off, the occupant detection ECU judges that the seat is being occupied by a child.

    8. When the ignition switch is turned to ON under the following conditions, the system performs an initial check and illuminates the AIRBAG OFF indicator light to indicate that the SRS front passenger airbag (instrument panel passenger airbag without door assembly) has been deactivated.

      A01T0N4E01

    9. When the judgment value is higher than criteria value "B", the occupant detection ECU judges that the seat is occupied by an adult.

    10. If the ignition switch is turned to ON in the following state, the system performs an initial check and illuminates the AIRBAG ON indicator light, indicating that the SRS front passenger airbag (instrument panel passenger airbag without door assembly), SRS front side airbag RH (front seat airbag assembly RH) and front seat outside belt assembly RH are active.

      A01T0MKE01

    11. After the ignition switch is turned to ON, the occupant detection ECU illuminates the AIRBAG ON/OFF indicator lights via the airbag sensor assembly based on the timing chart below in order to check the indicator light circuits:

      A01T0EBE06

  4. DIAGNOSIS


    1. If the occupant detection ECU detects a malfunction in the occupant classification system, the occupant detection ECU stores the malfunction data in memory. If the airbag sensor assembly detects a malfunction in the occupant detection ECU, the airbag sensor assembly illuminates the SRS airbag warning light and AIRBAG OFF indicator light.

    2. The occupant detection ECU outputs 5-digit Diagnostic Trouble Codes (DTCs) to the Global TechStream (GTS).

    3. The 5-digit DTCs can be read after connecting the Global TechStream (GTS) to the DLC3. For details, refer to the Repair Manual.