AIRBAG SYSTEM DETAILS


  1. FUNCTION OF MAIN COMPONENTS


    1. The SRS airbag system mainly consists of the parts listed in the table below.

      Component Outline
      Airbag Sensor Assembly

      • Detects the deceleration of the vehicle during a collision, determines whether ignition is necessary based on the signals from each airbag sensor, and transmits deployment signals to each airbag and seat belt pretensioner.

      • Provides initial check and diagnosis function.
      Airbag Assembly Mainly consists of an inflator and a bag. Upon receiving a deployment signal from the airbag sensor assembly, the inflator generates gas to deploy the bag.
      Airbag Sensor Detects the deceleration of the vehicle during a collision, and transmits the signal to the airbag sensor assembly, from which the airbag sensor assembly determines whether ignition is necessary.
      Front Passenger Side Seat Belt Buckle Switch Detects whether the front passenger seat belt is fastened or not based on the on/off status of the front passenger side seat belt buckle switch, and transmits on/off signals to the airbag sensor assembly.
      Airbag Cut-off Switch Transmits on/off signals to the airbag sensor assembly to manually turn on or off the deployment of the front passenger side airbags.
      SRS Warning Light Provided in the combination meter assembly and comes on when the SRS airbag system malfunctions.

  2. OPERATING CONDITION


    1. Ignition Condition


      1. G sensors used for the airbag system are installed on various parts on the vehicle and calculate the deceleration rate of each part during a collision.

      2. Depending on the situation, the airbag sensor assembly sends a deployment signal to each airbag based on the information from each sensor.

      3. Frontal collision signals are produced based on the information from the airbag sensor assembly and front airbag sensors. Frontal collision signals are used to deploy the airbags except the side airbags and curtain shield airbags.

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      4. The side airbags are deployed based on signals from the door side airbag sensors and airbag sensor assembly.

        Tech Tips

        The side curtain shield airbag is deployed at the same time.

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      5. The curtain shield airbag is deployed based on signals from the door side airbag sensors and airbag sensor assembly or the side airbag sensor assembly and airbag sensor assembly.

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      6. Rear collision signals are produced based on the information from the airbag sensor assembly and rear airbag sensors. Rear collision signals are used to deploy the airbags except the airbags for front or side collisions.

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  3. SYSTEM CONTROL


    1. Airbag for Frontal Collision


      1. For frontal collisions, there are 4 airbags and 2 seat belt pretensioners: a steering pad, front passenger airbag assembly, driver side knee airbag assembly, front passenger seat cushion airbag assembly, front seat outer belt assembly LH, and front seat outer belt assembly RH. The deployment of the airbags and the activation of the pretensioners occur simultaneously.

      2. The airbag sensor assembly determines whether the front passenger seat cushion airbag assembly should be deployed based on the signals received from the front passenger side seat belt buckle switch.

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    2. Airbag for Side/Side Rear Collision


      1. For severe side collisions there are 2 airbags: front seat side airbag assembly and curtain shield airbag assembly. These airbags deploy simultaneously. For severe side rear collisions only the curtain shield airbag assembly will deploy.

      2. For a side collision, if the door side airbag sensor detects an impact, it informs the airbag sensor assembly, and the airbag sensor assembly causes the front seat side and curtain shield airbag assemblies to be deployed simultaneously.

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      3. For a side rear collision, if the side airbag sensor assembly detects an impact, it informs the airbag sensor assembly via the door side airbag sensor, and the airbag sensor assembly causes the curtain shield airbag assembly to be deployed.

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    3. Airbag for Rear Collision


      1. For rear collisions, there is the rear window curtain shield airbag assembly. If the rear airbag sensor detects a rear impact, it informs the airbag sensor assembly about it via the door side airbag sensor and side airbag sensor assembly, and the airbag sensor assembly causes the rear window curtain shield airbag to be deployed.

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    4. Primary Check Illumination Control


      1. After the ignition switch is turned ON, the airbag sensor assembly illuminates the SRS warning light in the combination meter assembly for approximately 6 seconds and conducts the primary check. During the primary check, the ignition of airbags is prohibited and a diagnosis of the airbag sensor assembly is performed. If trouble is detected during the primary check, the SRS warning light remains on even after the 6 seconds have elapsed. See the illustration below.

      2. After the ignition switch is turned ON, the airbag sensor assembly operates the AIRBAG ON/OFF indicator lights as shown below to check for an open in the airbag cut-off switch indicator circuit.

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  4. FUNCTION


    1. Airbag Cut-off Switch


      1. The deployment of the front passenger airbag assembly and front passenger seat cushion airbag assembly can be prohibited by operating the airbag cut-off switch located on the lower portion of the instrument panel on the driver side. When the airbag cut-off switch is turned to OFF, these airbags will not be deployed even if a collision occurs.

      2. Turn the airbag cut-off switch ON and OFF by inserting the key and turning it.

      3. The AIRBAG ON/OFF indicator lights, which inform the driver of the airbag cut-off switch status, have been provided in the telltale light assembly on the upper portion of the instrument panel.

      4. The table below shows whether the airbags for the front passenger are enabled or disabled and the AIRBAG ON/OFF indicator lights come on or go off depending on the airbag cut-off switch status.

        Item Airbag Cut-off Switch Condition
        ON OFF Failure
        Front Passenger Airbag Assembly ○ X X
        Front Passenger Seat Cushion Airbag Assembly ○ X X
        Front Seat Side Airbag Assembly ○ ○ ○
        Front Seat Outer Belt Assembly for Front Passenger ○ ○ ○
        Curtain Shield Airbag Assembly for Front Passenger ○ ○ ○
        AIRBAG ON Indicator Light ○ X X
        AIRBAG OFF Indicator Light X ○ ○

        • ○: Enabled (Light comes on)

        • X: Disabled (Light goes off)

  5. CONSTRUCTION


    1. Steering Pad and Front Passenger Airbag Assembly


      1. The steering pad and front passenger airbag assembly mainly consists of an inflator and a bag.

    2. Driver Side Knee Airbag Assembly


      1. The driver side knee airbag assembly consists of an airbag door, an inflator, and a bag.

    3. Front Passenger Seat Cushion Airbag Assembly


      1. The front passenger seat cushion airbag assembly consists of an inflator and a bag.

    4. Curtain Shield Airbag Assembly


      1. Curtain shield airbag assemblies that extend from the front pillar to the roof side rail are installed. Each curtain shield airbag assembly consists of an inflator, a bag, and a cover.

    5. Rear Window Curtain Shield Airbag Assembly


      1. The rear window curtain shield airbag assembly is located on the rear header panel. It consists of an inflator and a bag.

    6. Front Seat Side Airbag Assembly


      1. Front seat side airbag assemblies are installed in the seat backs of the driver seat and the front passenger seat. Each front seat side airbag assembly consists of an inflator, a bag, and a cover.

    7. Front Airbag Sensor


      1. A deceleration sensor is enclosed in the front airbag sensor. Based on the deceleration of the vehicle during a front collision, a distortion is created in the sensor and converted into an electrical signal. Accordingly, the extent of the initial collision can be detected in detail.

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    8. Door Side and Side Airbag Sensors


      1. A deceleration sensor is enclosed in the door side airbag sensor and side airbag sensor assembly. Based on the deceleration of the vehicle during a side or side rear collision, a distortion is created in the sensor and converted into an electrical signal.

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    9. Rear Airbag Sensor


      1. A deceleration sensor is enclosed in the rear airbag sensor. Based on the deceleration of the vehicle during a rear collision, a distortion is created in the sensor and converted into an electrical signal.

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    10. Seat Belt Buckle Switch


      1. The built-in seat belt buckle switch of the front seat inner belt assembly detects that the seat belt is fastened. The seat belt buckle switch on the front passenger side is a non-contact type switch. This switch contains a Hall IC and magnet. When the seat belt is removed or inserted, the ejector, which is provided inside the seat belt buckle switch, and the plate, which is installed to the ejector, move. The movement of the plate changes the magnetic flux density of the magnet. The Hall IC detects changes in the magnetic flux density. These changes indicate that the seat belt is either fastened or unfastened, and the Hall IC outputs a signal to the airbag sensor assembly.

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        Tech Tips

        For the front seat belt warning, refer to the Meter/Gauge System Click here.

  6. DIAGNOSIS


    1. If the airbag sensor assembly detects a malfunction in the SRS airbag system, the airbag sensor assembly stores the malfunction data in memory, in addition to illuminating the SRS warning light.

    2. There are 2 types of DTC (Diagnostic Trouble Code) for the SRS airbag system: 5-digit and 2-digit.

    3. The 5-digit DTC can be read by connecting an intelligent tester II to DLC3.

    4. The 2-digit DTC can be read by connecting the SST (09843-18040) to the TC and CG terminals of the DLC3 and reading the blinking of the SRS warning light.

    5. If the SRS airbag deploys, the airbag sensor assembly will turn on the SRS warning light. However, different from the ordinary diagnosis function, a DTC will not be stored. The SRS warning light cannot be turned off. It is necessary to replace the airbag sensor assembly with a new one.

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