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Supplemental Restraint System: Precaution

CAUTION:
  • LEXUS LS430 is equipped with SRS, which consists of a driver airbag, front passenger airbag, driver knee airbag, front passenger knee airbag, side airbag and curtain shield airbag. Failure to carry out service operations in the correct sequence could cause the SRS to unexpectedly deploy during servicing, possibly leading to a serious accident. Further, if a mistake is made in servicing the SRS, it is possible that the SRS may fail to operate when required. Before performing servicing (including removal or installation of parts, inspection or replacement), be sure to read the following items carefully, then follow the correct procedures indicated in the repair manual.
  • Wait at least 90 seconds after the ignition switch is turned to the "LOCK" position and the negative (-) terminal cable is disconnected from the battery.

    (The SRS is equipped with a back-up power source, so that if work is started within 90 seconds after disconnecting the negative (-) terminal cable of the battery, the SRS may be deployed.)

  • Do not expose the horn button assy, front passenger airbag assy, instrument panel airbag assy lower No. 1, instrument panel airbag assy lower No.2, airbag sensor assy center, airbag sensor front, front seat airbag assy, side airbag sensor assy, curtain shield airbag assy, airbag sensor rear or seat position airbag sensor directly to hot air or flames.
NOTE:
  • Malfunction symptoms of the SRS are difficult to confirm, so DTCs are the most important source of information when troubleshooting. When troubleshooting the SRS, always inspect DTCs before disconnecting the battery.
  • Even in the case of a minor collision when the SRS does not deploy, the horn button assy, front passenger airbag assy, instrument panel airbag assy lower No. 1, instrument panel airbag assy lower No.2, airbag sensor assy center, airbag sensor front, front seat airbag assy, side airbag sensor assy, curtain shield airbag assy, airbag sensor rear and seat position airbag sensor should be inspected (see ON-VEHICLE INSPECTION  ).
  • Before repair work, remove the airbag sensor if any kind of shock is likely to occur to the airbag sensor during the operation.
  • Never use SRS parts from another vehicle. When replacing the parts, replace them with new ones.
  • Never disassemble or repair the horn button assy, front passenger airbag assy, instrument panel airbag assy lower No. 1, instrument panel airbag assy lower No.2, airbag sensor assy center, airbag sensor front, front seat airbag assy, side airbag sensor assy, curtain shield airbag assy, airbag sensor rear or seat position airbag sensor in order to reuse it.
  • If the horn button assy, front passenger airbag assy, instrument panel airbag assy lower No. 1, instrument panel airbag assy lower No.2, airbag sensor assy center, airbag sensor front, front seat airbag assy, side airbag sensor assy, curtain shield airbag assy, airbag sensor rear or seat position airbag sensor has been dropped, or if there are any cracks, dents or other defects in the case, bracket or connector, replace it with a new one.
  • Use a volt/ohmmeter with high impedance (10 kΩ/V minimum) for troubleshooting the electrical circuits.
  • Information labels are attached to the periphery of the SRS components. Follow the instructions in the caution.
  • After work on the SRS is completed, perform the SRS warning light check (see DIAGNOSIS SYSTEM ).
  • When the negative (-) terminal cable is disconnected from the battery, the memory of the clock and audio system will be canceled. So before starting work, make a record of the contents memorized orized in the audio memory system. When work is finished, reset the audio system as it was before and adjust the clock. Never use a back-up power supply from outside the vehicle to avoid erasing the memory in each memory system.
  • If the vehicle is equipped with a mobile communication system, refer to the precaution in the INTRODUCTION section (see PRECAUTION ).
  1. SRS CONNECTORS 

    HINT:

    SRS connectors are located as shown in the following illustration.

    Fig 1: Identifying SRS Connectors Location
    G03000038Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    CONNECTOR REFERENCE

    No. Connector Type Application
    (1) Terminal Twin-Lock Mechanism Connectors 2, 4, 6, 8, 10, 12, 13, 14, 17, 21, 23, 25
    (2) Activation Prevention Mechanism Connectors 2, 4, 18, 20, 22, 24, 26, 28, 30, 32, 34
    (3) Half Connection Prevention Mechanism Connectors 6, 8, 10, 13, 17, 21, 23, 25
    (4) Connector Lock Mechanism (1) Connectors 19, 27, 31, 33
    (5) Connector Lock Mechanism (2) Connectors 2, 4
    (6) Improper Connection Prevention Lock Mechanism Connectors 1, 3
    1. All connectors in the SRS are colored yellow to distinguish them from other connectors, except the seat position airbag sensor connector. Some connectors have special functions, and are specially designed for the SRS. These connectors use durable gold-plated terminals, and are placed in the locations shown on the previous page to ensure high reliability.
      1. Terminal twin-lock mechanism:

        Each connector has a two-piece component consisting of a housing and a spacer. This design enables the terminal to be locked securely by two locking devices (the retainer and the lance) to prevent terminals from coming out.

      2. Activation prevention mechanism:

        Each connector contains a short spring plate. When the connector is disconnected, the short spring plate automatically connects the positive (+) terminal and the negative (-) terminal of the squib.

        Fig 2: Identifying Terminal Twin-Lock Mechanism
        G03000039Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        Fig 3: Identifying Activation Prevention Mechanism
        G03000040Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      3. Half connection prevention mechanism:

        If the connector is not completely connected, the connector is disconnected due to the spring operation so that no continuity exists.

        Fig 4: Identifying Half Connection Prevention Mechanism
        G03000041Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      4. Connector lock mechanism (1):

        Locking the connector lock button connects the connector securely.

        Fig 5: Identifying Connector Lock Mechanism (1)
        G03000042Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      5. Connector lock mechanism (2):

        Both the primary lock with holder claws and the secondary lock with retainer claws prevent the connectors from becoming disconnected.

        Fig 6: Identifying Connector Lock Mechanism (2)
        G03000043Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      6. Improper connection prevention lock mechanism:

        When connecting the holder, the lever is pushed into the end by rotating around the A axis to lock the holder securely.

      Fig 7: Identifying Improper Connection Prevention Lock Mechanism
      G03000044Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. When the vehicle is involved in a frontal collision in the hatched area (Fig 8) and the shock is larger than the predetermined level, the SRS is activated automatically. The safing sensor is designed to go on at a smaller deceleration rate than the airbag sensor. As illustrated in Fig 8 below, when both the safing sensor and deceleration sensor go on simultaneously, current flows to the squib and ignition occurs. When a deceleration force acts on the sensors, 4 squibs in the driver airbag, front passenger airbag, driver knee airbag and front passenger knee airbag ignite and generate gas. The gas discharging into the driver airbag, front passenger airbag, driver knee airbag and front passenger knee airbag rapidly increases the pressure inside the bags, breaking the horn button assy, instrument panel, instrument panel airbag assy lower No. 1 and instrument panel airbag assy lower No.2. The deployment of the bags then ends, and the bags deflate as the gas is discharged through discharge holes at the bag's rear or side.
      Fig 8: Identifying Hatched Area Of Vehicle
      G03000045Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. DISCONNECTION OF CONNECTORS FOR HORN BUTTON ASSY, INSTRUMENT PANEL AIR-BAG ASSY LOWER No. 1 AND INSTRUMENT PANEL AIRBAG ASSY LOWER No.2 
    1. Release the lock button (yellow part) of the connector using a screwdriver.
    2. Insert the screwdriver tip between the connector and the base, and then raise the connector.
    Fig 9: Disconnection Procedure Of Connectors For Horn Button Assy
    G03000046Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. CONNECTION OF CONNECTORS FOR HORN BUTTON ASSY, INSTRUMENT PANEL AIRBAG ASSY LOWER No. 1 AND INSTRUMENT PANEL AIRBAG ASSY LOWER No.2 
    1. Connect the connector.
    2. Push down securely on the lock button (yellow part) of the connector. (When locking, a click sound can be heard.)
    Fig 10: Connection Procedure Of Connectors For Horn Button Assy
    G03000047Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. DISCONNECTION OF CONNECTOR FOR FRONT SEAT AIRBAG ASSY 
    1. Place a finger on the slider.
    2. Slide the slider to release lock.
    3. Disconnect the connector.
    Fig 11: Disconnection Procedure Of Connector For Front Seat Airbag Assy
    G03000048Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  5. CONNECTION OF CONNECTOR FOR FRONT SEAT AIRBAG ASSY 
    1. Connect the connector as shown in the illustration. (When locking, make sure that the slider returns to its original position and a click sound can be heard.)

      HINT:

      When connecting, the slider will slide. Be sure not to touch the slider while connecting, as it may result in an insecure fit.

    Fig 12: Connection Procedure Of Connector For Front Seat Airbag Assy
    G03000049Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  6. DISCONNECTION OF CONNECTOR FOR AIRBAG SENSOR ASSY CENTER 
    1. Pull the lever by pushing part A as shown in the illustration and remove the holder (with connectors).
      Fig 13: Disconnection Procedure Of Connector For Airbag Sensor Assy Center
      G03000050Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      Perform the following procedures when replacing the holder.

    2. Remove the holder.
      1. Using a screwdriver, unlock the retainer.
        Fig 14: Unlocking Retainer
        G03000051Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. Release the lance fittings and remove the holder.
      Fig 15: Removing Holder
      G03000052Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Install the holder.
      1. Install the connectors to the holder. (When locking, a click sound can be heard.)

    HINT:

    The retainer is locked when the holder is connected.

    Fig 16: Installing Holder
    G03000053Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  7. CONNECTION OF CONNECTOR FOR AIRBAG SENSOR ASSY CENTER 
    1. Firmly insert the holder (with connectors) until it can not be pushed any further.
    2. Push the lever to connect the holder (with connectors). (When locking, a click sound can be heard.)

      HINT:

      The holder slides when connected. Holding the holder when connecting may result in an insecure connection.

      Fig 17: Connection Procedure Of Connector For Airbag Sensor Assy Center
      G03000054Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  8. DISCONNECTION OF CONNECTORS FOR AIRBAG SENSOR FRONT, SIDE AIRBAG SENSOR AND AIRBAG SENSOR REAR 
    1. While holding both outer flank sides, slide the outer in the direction shown by the arrow.
    2. When the connector lock is released, the connectors are disconnected.

    HINT:

    Be sure to hold both outer flank sides. Holding the top and bottom sides will make disconnection difficult.

    Fig 18: Sliding Outer
    G03000055Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    Fig 19: Disconnection Procedure Of Connectors For Airbag Sensor Front
    G03000056Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  9. CONNECTION OF CONNECTORS FOR AIRBAG SENSOR FRONT, SIDE AIRBAG SENSOR AND AIRBAG SENSOR REAR 
    1. Connect the connector as shown in the illustration. (When locking, make sure that the outer returns to its original position and a click sound can be heard.)

    HINT:

    When connecting, the outer will slide. Be sure not to hold the outer while connecting, as it may result in an insecure fit.

    Fig 20: Connection Procedure Of Connectors For Airbag Sensor Front
    G03000057Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  10. DISCONNECTION OF CONNECTORS FOR FRONT PASSENGER AIRBAG ASSY AND CURTAIN SHIELD AIRBAG ASSY 
    1. Place a finger on the slider.
    2. Slide the slider to release lock.
    3. Disconnect the connector.
    Fig 21: Disconnection Procedure Of Connectors For Front Passenger Airbag Assy And Curtain Shield Airbag Assy
    G03000058Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  11. CONNECTION OF CONNECTORS FOR FRONT PASSENGER AIRBAG ASSY AND CURTAIN SHIELD AIRBAG ASSY 
    1. Connect the connector as shown in the illustration. (When locking, make sure that the slider returns to its original position and a click sound can be heard.)

      HINT:

      When connecting, the slider will slide. Be sure not to touch the slider while connecting, as it may result in an insecure fit.

      Fig 22: Connecting Of Connectors For Front Passenger Airbag Assy And Curtain Shield Airbag Assy
      G03000059Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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