OCCUPANT CLASSIFICATION SYSTEM DETAILS


  1. FUNCTION OF MAIN COMPONENTS


    1. The main components 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 2 occupant detection sensors and front passenger seat belt buckle switch.
      Occupant Detection Sensor (Rear LH or RH) The sensors are strain gauge type sensors that send signals to the occupant detection ECU in accordance with the weight of the occupant.
      Front Passenger Seat Belt Buckle Switch (Front Seat Inner Belt Assembly RH) The front passenger seat belt buckle switch detects if the front passenger seat belt is fastened.
      Combination Meter Assembly SRS Warning Light The SRS warning light turns on to alert the driver when the airbag sensor assembly detects a malfunction in the airbag system.
      Air Conditioning Control Assembly AIRBAG ON/OFF Indicator Lights

      • The AIRBAG ON/OFF indicator lights inform the driver whether the occupant detection ECU puts the instrument panel passenger airbag without door assembly, lower No. 2 instrument panel airbag assembly and front passenger outer belt assembly RH into an active state or inactive state.

      • If a malfunction occurs in the occupant detection system, the AIRBAG OFF indicator light and SRS warning light come on.

  2. OPERATING CONDITION


    1. The front passenger SRS items and indicator lights operate as follows according to the occupant detection:

      Items Occupant Classification
      Adult Child Child Seat Unoccupied Malfunction
      Front Passenger SRS Components Front Airbag ○ X X X X
      Knee Airbag ○ X X X X
      Side Airbag ○ ○ ○ ○ ○
      Curtain Shield Airbag ○ ○ ○ ○ ○
      Seat Belt Pretensioner ○ ○ ○ X ○
      AIRBAG ON/OFF Indicator Lights ON Indicator Light ON OFF OFF OFF OFF
      OFF Indicator Light OFF ON ON OFF ON

      • ○: Deploys

      • X: Does not deploy

  3. SYSTEM CONTROL


    1. Unoccupied Judgment


      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 18 kg (39.7 lb), and disables the instrument panel passenger airbag without door assembly and lower No. 2 instrument panel airbag assembly.

      3. The occupant detection ECU contains criteria value "A" to judge whether the seat is occupied by a child or a child seat in accordance with the signals from the 2 occupant detection sensors and front seat inner belt assembly, and criteria value "B" to judge whether the occupant is an adult or child (with child seat).

      4. The occupant detection ECU makes an unoccupied judgment when the judgment value is lower than criteria value "A" and the front passenger seat belt buckle switch is off.

      5. If the ignition switch is turned to ON this state, the system performs an initial check, and does not illuminate the AIRBAG ON/OFF indicator lights. Then, the system prohibits the deployment of the instrument panel passenger airbag without door assembly, lower No. 2 instrument panel airbag assembly and front seat outer belt assembly RH, and does not blink the seat belt warning light.

        A01HWC2E01

    2. Child Seat or Child Judgment


      1. If the judgment value is lower than criteria value "B" and the front seat inner belt assembly RH (front passenger seat belt buckle switch) is ON, the occupant detection ECU judges that a child seat is installed.

      2. If the judgment value is higher than criteria value "A", but lower than criteria value "B", and the front seat inner belt assembly RH (front passenger seat belt buckle switch) is OFF, the occupant detection ECU judges that the seat is being occupied by a child.

      3. When the ignition switch is turned to ON under these conditions, the system performs an initial check and illuminates the AIRBAG OFF indicator light to indicate that the instrument panel passenger airbag without door assembly and lower No. 2 instrument panel airbag assembly have been deactivated.

        A01HWQUE01

    3. Adult Judgment


      1. After the occupant detection ECU judges that a child seat is installed, the AIRBAG OFF indicator light does not go off unless the front seat inner belt assembly RH (front passenger seat belt buckle switch) is turned OFF.

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

      3. If the ignition switch is turned to ON in this state, the system performs an initial check and illuminates the AIRBAG ON indicator light, indicating that the instrument panel passenger airbag without door assembly, lower No. 2 instrument panel airbag assembly, front seat side airbag assembly RH and front passenger outer belt assembly RH are active.

        A01HWH9E01

      4. After the occupant detection ECU judges that the occupant is an adult, and if the judgment value is determined as criteria value "A" or less according to occupant load movement and the front passenger seat belt buckle switch (front seat inner belt assembly RH) is off, the ECU continues adult judgment for approximately 20 seconds before switching to the unoccupied judgment.

    4. Initial Check


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

        A01HWQTE13

  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 warning light and AIRBAG OFF indicator light.

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

    3. The 5-digit DTCs can be read after connecting the Techstream to the DLC3. For details, refer to the Repair Manual.