AIRBAG SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


    1. The main components of the airbag system have the following functions:

      Component Function
      Airbag Sensor Assembly

      • In the event of a frontal collision, the airbag sensor assembly receives signals from either of the front airbag sensors. The airbag sensor assembly receives the signal via its judgment circuit and also receives another signal from the safing sensor built into the airbag sensor assembly. After receiving a signal from at least one of the front airbag sensors and the safing sensor, the airbag sensor assembly determines whether the driver airbag, front passenger airbag, driver knee airbag, front passenger knee airbag and curtain shield airbags should be deployed and the front seat belt pretensioners and rear seat belt pretensioners*1 should be activated. The airbag sensor assembly also diagnosis system malfunctions.

      • In the event of a side or rear side collision, the airbag sensor assembly receives signals from the side airbag sensor assembly or rear airbag sensor. The airbag sensor assembly receives the signal via its judgment circuit and also receives another signal from the safing sensor built into the airbag sensor assembly. After receiving a signal from at least one of the side sensors and the safing sensor, the airbag sensor assembly determines whether the front seat airbag assemblies, rear seat airbag assemblies*2 and curtain shield airbag assemblies should be deployed and the front seat belt pretensioner should be activated. The airbag sensor assembly also diagnosis system malfunctions.

      • If the vehicle collides with a pedestrian, the airbag sensor assembly judges if ignition is necessary based on the signal from the pedestrian protection sensors and sends the ignition signal to the pop up hood lifter assembly.

      • Sends the collision detection signal to the ECM through the Controller Area Network (CAN) to operate fuel pump control.

      • Sends the collision detection signal to the main body ECU (multiplex network body ECU) to operate the collision door lock release function.

      • Sends the collision detection signal to the hybrid vehicle control ECU assembly to shut down the hybrid system power supply.

      • Sends the airbag deployment signal to the telematics transceiver (data communication module) for the emergency call of automatic collision notification service.*6
      Horn Button Assembly Driver Side Squib Used as supplements to the seat belts to help reduce impact to the occupants.
      Instrument Panel Passenger Airbag without Door Assembly Front Passenger Side Squib
      Lower No. 1 Instrument Panel Airbag Assembly Driver Knee Airbag Squib
      Lower No. 2 Instrument Panel Airbag Assembly Front Passenger Knee Airbag Squib
      Front Seat Airbag Assembly LH/RH Front Side Airbag Squib LH/RH
      Rear Seat Airbag Assembly LH/RH*2 Rear Side Airbag Squib LH/RH
      Curtain Shield Airbag Assembly LH/RH Curtain Shield Squib LH/RH
      Front Airbag Sensor LH/RH Based on the deceleration of the vehicle during a frontal collision, distortion is created in the sensor and is converted into an electrical signal.
      Side Airbag Sensor Assembly LH/RH Based on the deceleration of the vehicle during a side or rear side collision, distortion is created in the sensor and is converted into an electrical signal.
      Rear Airbag Sensor LH/RH
      Front Seat Outer Belt Assembly LH/RH Front Pretensioner Squib LH/RH The front seat outer belt assemblies are used to help reduce impact to the occupants.
      Rear Seat 3 Point Type Outer Belt Assembly LH/RH*1 Rear Pretensioner Squib LH/RH The rear seat 3 point type outer belt assemblies are used to help reduce impact to the occupants.
      Seat Position Airbag Sensor The seat position airbag sensor detects the slide position of the driver seat.
      Driver Seat Belt Buckle Switch (Front Seat Inner Belt Assembly LH*3/RH*4) The driver seat belt buckle switch detects if the driver seat belt is fastened.
      Hybrid Vehicle Control ECU Assembly Receives the collision detection signal from the airbag sensor assembly during a collision and shuts down the hybrid system power supply by turning the System Main Relays (SMRs) off, in order to ensure safety.
      Airbag Cut Off Switch Cylinder Sub-assembly*5 The airbag cut off switch cylinder sub-assembly suspends the instrument panel passenger airbag without door assembly and lower No. 2 instrument panel airbag assembly operations.
      Air Conditioning Control Assembly*5 AIRBAG OFF Indicator Light The airbag ON/OFF indicator lights inform the occupants of the airbag cut off switch cylinder sub-assembly status.
      AIRBAG ON Indicator Light
      Skid Control ECU Assembly Sends the vehicle speed signal to the airbag sensor assembly.
      Pop Up Hood Sensor Assembly Pedestrian Protection Sensor (LH/RH) When the front bumper of the vehicle collides with a pedestrian, the pedestrian protection sensor detects changes in the pedestrian detection chamber pressure and sends signals to the airbag sensor assembly for the ignition judgment.
      Pop Up Hood Lifter Assembly LH/RH Consists of an inflator, cylinder and piston. On receiving the ignition signal from the airbag sensor assembly, the inflator is ignited, instantly pushing up the piston and raising the engine hood.
      ECM The fuel pump is stopped when an SRS airbag is deployed in a frontal collision, side collision or rear side collision.
      Main Body ECU (Multiplex Network Body ECU) Receives an airbag deployment signal from the airbag sensor assembly and operates the collision door lock release function.
      Combination Meter Assembly SRS Warning Light Turns on to alert the driver when the airbag sensor assembly detects a malfunction in the airbag system.
      Multi-information Display Displays a warning message to inform the driver of a malfunction in the system.
      Master Warning Light Turns on to alert the driver when the airbag sensor assembly detects a malfunction in the system.
      Buzzer Sounds to warn the driver of a malfunction in the system.
      Telematics Transceiver (Data Communication Module)*6 Receives an airbag deployment signal from the airbag sensor assembly, and automatically makes the emergency call of automatic collision notification service.

      *1: Models with rear pretensioners

      *2: Models with rear seat airbags

      *3: LHD models

      *4: RHD models

      *5: Models with airbag cut off switch cylinder

      *6: Models with manual (SOS) switch

  2. SYSTEM CONTROL


    1. Airbag for Frontal Collision


      1. There are 6 airbags which deploy in the event of a frontal collision: the horn button assembly, instrument panel passenger airbag without door assembly, lower No. 1 instrument panel airbag assembly, lower No. 2 instrument panel airbag assembly and curtain shield airbag assemblies. These airbags deploy simultaneously. The horn button assembly and instrument panel passenger airbag without door assembly use dual-stage control. In addition, each front pretensioner contained in a front seat outer belt assembly, and each rear pretensioner contained in a rear seat 3 point type outer belt assembly* are also activated.

        *: Models with rear pretensioners

      2. The airbag sensor assembly detects the information in the table below from various sources in order to activate the dual-stage control.

      3. For a frontal collision, if a front airbag sensor detects an impact, it informs the airbag sensor assembly. The airbag sensor assembly causes the horn button assembly, instrument panel passenger airbag without door assembly, lower No. 1 instrument panel airbag assembly, lower No. 2 instrument panel airbag assembly and curtain shield airbag assemblies to deploy. Additionally, the airbag sensor assembly activates the seat belt pretensioners for the driver, front passenger and rear passengers*.

        *: Models with rear pretensioners

        Airbag Information Source
        Driver Extent of Impact

        • Front Airbag Sensor LH or RH

        • Airbag Sensor Assembly
        Driver Seat Position Seat Position Airbag Sensor
        Seat Belt Condition Driver Seat Belt Buckle Switch (Front Seat Inner Belt Assembly LH*1/RH*2) (Non-contact Type)
        Front Passenger Extent of Impact

        • Front Airbag Sensor LH or RH

        • Airbag Sensor Assembly
        Rear Passenger Extent of Impact

        • Front Airbag Sensor LH or RH

        • Airbag Sensor Assembly

        *1: LHD models

        *2: RHD models

        B003XJFE01
        B003XMCE01

      4. Deceleration sensors used for the airbag system are installed on various parts on the vehicle and calculate the deceleration (or acceleration) rate of each part during a collision.

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

      6. 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 and activate the pretensioners as indicated in the table below. The side airbags and rear side airbags* are not deployed in a frontal collision.

        *: Models with rear seat airbags

        Figure 1. Frontal Collision

        B003XKRE02

    2. Airbag for Side/Rear Side Collision


      1. There are 3 airbags which deploy in the event of a severe side collision: the front seat airbag assembly, rear seat airbag assembly* and curtain shield airbag assembly. These airbags deploy simultaneously. Additionally, at the same time, the front seat outer belt assembly is also activated.

        *: Models with rear seat airbags

      2. For a side collision, if the side airbag sensor assembly detects an impact, it informs the airbag sensor assembly via the rear airbag sensor, and the airbag sensor assembly causes the front seat airbag assembly, rear seat airbag assembly* and curtain shield airbag assembly to deploy simultaneously, and activates the front seat outer belt assembly.

        *: Models with rear seat airbags

        B003XJNE01

      3. The front seat airbag assembly, rear seat airbag assembly* and curtain shield airbag assembly are deployed and the front pretensioner in the front seat outer belt assembly is activated based on signals from the side airbag sensor assemblies and airbag sensor assembly.

        *: Models with rear seat airbags

        Figure 2. Side Collision

        B003XM5E03

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

        *: Models with rear seat airbags

        B003XMSE01

      5. The rear seat airbag assembly* and curtain shield airbag assembly are deployed based on signals from the rear airbag sensors or the side airbag sensor assemblies and the airbag sensor assembly.

        *: Models with rear seat airbags

        Figure 3. Rear Side Collision

        B003XMKE01

    3. Pedestrian Collision


      1. The pop up hood operates when the pressure change is detected in the chamber of the pop up hood sensor assembly in case that the vehicle (front bumper) collides with a pedestrian.

      2. The pop up hood is designed to pop up in a collision with a pedestrian when driving at approximately 25 to 55 km/h (16 to 34 mph).

        Note

        The pop up hood pops up when the front bumper collides with a pedestrian or any obstacle.

      3. For a pedestrian collision, if a pedestrian protection sensor detects an impact, it informs the airbag sensor assembly and causes the pop up hood lifter assemblies to be deployed.

        B003XM2E01

      4. The pop up hood lifter assemblies are deployed based on signals from the pedestrian protection sensors, skid control ECU assembly, and airbag sensor assembly.

        B003XKPE01

    4. Primary Check Illumination Control


      1. After the power switch is turned on (IG), 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 a malfunction is detected during the primary check, the SRS warning light will remain on even after 6 seconds have elapsed.

      2. After the power switch is turned on (IG), the airbag sensor assembly operates the passenger airbag ON/OFF indicator lights as shown below to check for an open in the indicator light circuits.

        B003XNDE50

  3. 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. The airbag sensor assembly outputs malfunction data and 5-digit Diagnostic Trouble Codes (DTCs) to the Global TechStream (GTS).

    3. The 5-digit DTCs can be read by connecting the Global TechStream (GTS) to the DLC3. For details, refer to the Repair Manual.

    4. If the SRS airbags deploy, the airbag sensor assembly will turn on the SRS warning light. However, unlike an ordinary malfunction, a DTC will not be stored. The SRS warning light cannot be manually turned off. It is necessary to replace the airbag sensor assembly with a new one.