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Home >> Toyota >> 2006 >> Avalon XLS >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Supplemental Restraint System >> Airbag System >> Precaution

Airbag System: Precaution

CAUTION:
  • The vehicle is equipped with a Supplemental Restraint System (SRS). It consists of a driver airbag, front passenger airbag, driver side knee airbag, front seat 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 article.
  • Wait at least 90 seconds after the ignition switch is turned off and the negative (-) terminal cable is disconnected from the battery before starting the operation.

    (The SRS is equipped with a backup 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 steering pad, front passenger airbag assembly, driver side knee airbag assembly, center airbag sensor assembly, front airbag sensor, front side seat airbag assembly, side airbag sensor, curtain shield airbag assembly, rear airbag sensor, seat position airbag sensor or occupant classification ECU directly to hot air or flames.
  • Be sure to perform the initialization of the occupant classification ECU if any of the following conditions occur (See INITIALIZATION ). If the initialization is not performed, the SRS may not operate properly.
    • The occupant classification ECU is replaced.
    • Accessories (seatback tray, seat cover, etc.) are installed to the vehicle.
    • The passenger seat is removed from the vehicle, and then reinstalled or replaced.
    • The passenger airbag ON/OFF indicator ("OFF") comes on when the passenger seat is not occupied.
    • The vehicle is brought to the workshop for repair due to an accident or collision.
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 steering pad, front passenger airbag assembly, driver side knee airbag assembly, center airbag sensor assembly, front airbag sensor, front side seat airbag assembly, side airbag sensor, curtain shield airbag assembly, rear airbag sensor, seat position airbag sensor and occupant classification ECU should be inspected.
  • Before repair work, remove the airbag sensor if any kind of shock is likely to occur to the airbag sensor during the repair.
  • Never use SRS parts from another vehicle. When replacing parts, replace them with new ones.
  • Never disassemble or repair any of the following parts in order to reuse them. If any of these parts have been dropped, or a defect is found (e.g. cracks, dents or any other defects) in any of the housings, brackets or connectors, then replace the part with a new one.
    • Steering Pad
    • Front Passenger Airbag Assembly
    • Driver Side Knee Airbag Assembly
    • Front Side Seat Airbag Assembly
    • Curtain Shield Airbag Assembly
    • Center Airbag Sensor Assembly
    • Front Airbag Sensor
    • Side Airbag Sensor
    • Rear Airbag Sensor
    • Seat Position Airbag Sensor
    • Occupant Classification ECU
NOTE:
  • Use a volt/ohmmeter with high impedance (10 k/V minimum) for troubleshooting the electrical circuits.
  • Information labels are attached near 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 will be cleared. Because of this, be sure to make a record of the contents memorized in each system before starting work. When work is finished, adjust each system as it was before. Never attempt to avoid erasing vehicle system memories by using a backup power supply from outside the vehicle.
  • If the vehicle is equipped with a mobile communication system, refer to the PRECAUTION in the INTRODUCTION article.
  1. HANDLING PRECAUTIONS FOR AIRBAG SENSORS 

    HINT:

    In this article, the center airbag sensor assembly, front airbag sensor LH and RH, side airbag sensor LH and RH, rear airbag sensor LH and RH are collectively referred to as the airbag sensors.

    1. Before starting the following operations, wait at least 90 seconds after disconnecting the negative (-) cable of the battery:
      1. Replacement of the airbag sensors.
      2. Adjustment of the front/rear doors of the vehicle equipped with the side airbag and curtain shield airbag (fitting adjustment).
    2. When connecting or disconnecting the airbag sensor connectors, ensure that all of the sensors are installed in the vehicle.
    3. Do not use airbag sensors which have been dropped during the operation or transportation.
    4. Do not disassemble the airbag sensors.
  2. INSPECTION PROCEDURE FOR VEHICLE INVOLVED IN ACCIDENT 
    1. When the airbag has not deployed, confirm the DTC by checking the SRS warning light. If there is any malfunction in the SRS airbag system, perform troubleshooting.
    2. When any of the airbags have deployed, replace the airbag sensor and check the installation condition.
  3. EXPRESSIONS OF IGNITION SWITCH 

    The type of ignition switch used on this model differs according to the specifications of the vehicle.

    The expressions listed in the table below are used in this article.

    IGNITION SWITCH SPECIFICATION

    Switch Type Ignition Switch (position) Engine Switch (condition)
    Expression Ignition Switch off LOCK Off
    Ignition Switch on (IG) ON On (IG)
    Ignition Switch on (ACC) ACC On (ACC)
    Engine Start START Start
  4. SRS CONNECTORS 

    HINT:

    SRS connectors are located as shown in Fig 1.

    Fig 1: Supplemental Restraint System Communication Diagram
    G04378351Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    SRS CONNECTORS SPECIFICATION

    No. Connector Type Application
    (1) Terminal Twin-Lock Mechanism Connectors 6, 8, 10, 12, 15, 16, 17, 18, 19, 21, 22, 27, 28, 32
    (2) Activation Prevention Mechanism Connectors 20, 22, 24, 26, 28, 30, 32, 34
    (3) Half Connection Prevention Mechanism Connectors 6, 8, 10, 16, 19, 21, 27, 31
    (4) Connector Position Assurance Mechanism Connector 6
    (5) Connector Lock Mechanism (1) Connectors 23, 25, 29, 31, 33
    (6) Connector Lock Mechanism (2) Connectors 2, 4
    (7) Improper Connection Prevention Lock Mechanism Connectors 1, 3
    1. All connectors in the SRS, except the seat position airbag sensor connector and the occupant classification ECU connectors, are colored yellow to distinguish them from other connectors. These connectors have special functions, and are specially designed for the SRS. All SRS connectors use durable gold-plated terminals, and are placed in the locations shown in Fig 1 to ensure high reliability.
      Fig 2: Identifying Male And Female Connector
      G04378352Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Terminal twin-lock mechanism: All connectors with a terminal twin-lock mechanism have 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:
        Fig 3: Identifying Short Spring Plate
        G04378353Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        All connectors with an activation prevention mechanism contain a short spring plate. When these connectors are disconnected, the short spring plate creates a short circuit by automatically connecting the positive (+) and negative (-) terminals of the squib.

      3. Half connection prevention mechanism:
        Fig 4: Identifying Half Connection Prevention Mechanism
        G04378354Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

      4. Connector position assurance mechanism:
        Fig 5: Identifying Connector Position Assurance Mechanism
        G04378355Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Only when the housing lock (white part) is completely engaged, the CPA (yellow part) slides, which completes the connector engagement.

      5. Connector lock mechanism (1):
        Fig 6: Identifying Connector Lock Mechanism (1)
        G04378356Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Locking the connector lock button connects the connector securely.

      6. Connector lock mechanism (2):
        Fig 7: Identifying Connector Lock Mechanism (2)
        G04378357Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

      7. Improper connection prevention lock mechanism:
        Fig 8: Identifying Improper Connection Prevention Lock Mechanism
        G04378358Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

  5. DISCONNECTION OF CONNECTORS FOR STEERING PAD, FRONT PASSENGER AIRBAG ASSEMBLY (SQUIB SIDE), CURTAIN SHIELD AIRBAG ASSEMBLY AND DRIVER SIDE KNEE AIRBAG ASSEMBLY 
    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: Inserting Screwdriver Tip Between Connector And Base
      G04378359Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  6. CONNECTION OF CONNECTORS FOR STEERING PAD, FRONT PASSENGER AIRBAG ASSEMBLY (SQUIB SIDE), CURTAIN SHIELD AIRBAG ASSEMBLY AND DRIVER SIDE KNEE AIRBAG ASSEMBLY 
    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: Pushing Down Securely On Lock Button Of Connector
      G04378360Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  7. DISCONNECTION OF CONNECTOR FOR FRONT PASSENGER AIRBAG ASSEMBLY (INSTRUMENT PANEL WIRE SIDE) 
    1. Place a finger on the slider, slide the slider to release the lock, and then disconnect the connector.
      Fig 11: Sliding Slider To Release Lock
      G04378361Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  8. CONNECTION OF CONNECTOR FOR FRONT PASSENGER AIRBAG ASSEMBLY (INSTRUMENT PANEL WIRE SIDE) 
    1. Connect the connector as shown in Fig 12. (When locking, make sure that the slider returns to its original position and a click sound can be heard.)
      Fig 12: Connecting Connector
      G04378362Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

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

  9. DISCONNECTION OF CONNECTOR FOR FRONT SEAT SIDE AIRBAG ASSEMBLY 
    1. Place a finger on the slider, slide the slider to release the lock, and then disconnect the connector.
      Fig 13: Sliding Slider To Release Lock
      G04378363Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  10. CONNECTION OF CONNECTOR FOR FRONT SEAT SIDE AIRBAG ASSEMBLY 
    1. Connect the connector as shown in Fig 14. (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 14: Connecting Connector
      G04378364Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  11. DISCONNECTION OF CONNECTOR FOR CENTER AIRBAG SENSOR ASSEMBLY 
    1. Pull the lever by pushing part A as shown in Fig 15 and disconnect the holder (with connectors).
      Fig 15: Pulling Lever By Pushing Part A
      G04378365Courtesy 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 16: Unlocking Retainer With Screwdriver
        G04378366Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. Release the fitting lance and remove the holder.
        Fig 17: Releasing Fitting Lance And Removing Holder
        G04378367Courtesy 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.

  12. CONNECTION OF CONNECTOR FOR CENTER AIRBAG SENSOR ASSEMBLY 
    1. Firmly insert the holder (with connectors) into the airbag sensor assembly center until it cannot be pushed any further.
      Fig 18: Installing Connectors To Holder
      G04378368Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Push the lever to connect the holder (with connectors). (When locking, a click sound can be heard.)

      HINT:

      The holder slides in to the center airbag sensor assembly when it is being connected. Be sure not to hold the holder while connecting, as it may result in an insecure fit.

      Fig 19: Pushing Lever To Connect Holder
      G04378369Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  13. DISCONNECTION OF CONNECTOR FOR FRONT AIRBAG SENSOR 
    1. Push down the housing lock (white part) and slide the CPA (yellow part). (At this time, the connector cannot be disconnected yet).
    2. Push down the housing lock (white part) again and disconnect the connector.
      Fig 20: Pushing Down Housing Lock And Slide CPA
      G04378370Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      Do not push down the A part shown in Fig 21 when disconnecting.

    3. After disconnecting the connector, check that the position of the housing lock (white part) is as shown in Fig 21.
      Fig 21: Checking Position Of Housing Lock
      G04378371Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  14. CONNECTION OF CONNECTOR FOR FRONT AIRBAG SENSOR 
    1. Before connecting the connectors, check that the position of the housing lock (white part) is as shown in Fig 22.
      Fig 22: Checking Position Of Housing Lock
      G04378372Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Be sure to engage the connectors until they are locked. (When locking, make sure that a click sound can be heard.)

      HINT:

      When connecting them, the housing lock (white part) slides. Be sure not to hold the housing lock (white part) and A part, as it may result in an insecure fit.

      Fig 23: Checking Housing Lock
      G04378373Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  15. DISCONNECTION OF CONNECTORS FOR SIDE AIRBAG SENSOR AND REAR AIRBAG SENSOR 
    1. While holding both the sides of the outer connector locking sleeve, slide the outer in the direction shown in Fig 24 by the arrow.
      Fig 24: Sliding Outer Connector Locking Sleeve
      G04378374Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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 will make disconnection difficult.

      Fig 25: Identifying Connector Lock
      G04378375Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  16. CONNECTION OF CONNECTORS FOR SIDE AIRBAG SENSOR AND REAR AIRBAG SENSOR 
    1. Connect the connector as shown in tFig 26. (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 26: Connecting Connector
G04378376Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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