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 4 occupant detection sensors and front passenger seat belt buckle switch.
      Occupant Detection Sensor (Front LH/RH, Rear LH/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, such as a malfunction in the occupant detection system.
      Accessory Meter Assembly AIRBAG ON/OFF Indicator Lights The AIRBAG ON indicator light informs the driver that the occupant detection ECU puts the instrument panel passenger airbag without door assembly and front seat outer belt assembly RH into an active state.

  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 ○ ○ ○ ○ ○
      Side Airbag ○ ○ ○ ○ ○
      Curtain Shield Airbag ○ ○ ○ ○ ○
      Seat Belt Pretensioner ○ ○ ○ ○ ○
      AIRBAG ON/OFF Indicator Lights ON Indicator Light ON ON ON ON ON
      OFF Indicator Light OFF OFF OFF OFF OFF

      Tech Tips

      ○: Deploys

  3. SYSTEM CONTROL


    1. Summary


      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. 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 4 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).

      3. This system recognizes the occupant as a child or child seat if it detects a weight of less than "B".

    2. Unoccupied Judgment


      1. 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.

      2. 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 and front seat side airbag assembly RH are active.

        A01F0SAE02

    3. 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. 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 and front seat side airbag assembly RH are active.

        A01F0UDE01

    4. Adult Judgment


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

      2. 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 and front seat side airbag assembly RH are active.

        A01F0R5E01

    5. Initial Check


      1. After the ignition switch is turned 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.

        A01F0QDE01

  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.

    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.