AIRBAG SYSTEM CONTROL AIRBAG CONTROL

  1. FUNCTION OF MAIN COMPONENTS

    1. The main components of the SRS 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 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 front airbag sensor and the safing sensor, the airbag sensor assembly determines whether the driver airbag, front passenger airbag, curtain shield airbags* and front seat belt pretensioners should be deployed. The airbag sensor assembly also diagnoses 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 side No. 2 airbag sensor assembly*. 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 airbags, curtain shield airbags* and front seat belt pretensioners should be deployed. The airbag sensor assembly also diagnoses system malfunctions.

      • The airbag sensor assembly sends an airbag deployment signal to the ECM through the Controller Area Network (CAN) to operate fuel pump control.

      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

      Front Seat Airbag Assembly LH/RH

      Front Side Airbag Squib LH/RH

      Curtain Shield Airbag Assembly LH/RH*

      Curtain Shield Squib LH/RH

      Front Airbag Sensor

      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.

      Side No. 2 Airbag Sensor Assembly LH/RH*

      Front Seat Outer Belt Assembly LH/RH

      Front Pretensioner Squib LH/RH

      Used to help reduce impact to the occupants.

      Airbag Cut Off Switch Cylinder Sub-assembly

      Suspends the instrument panel passenger airbag without door assembly operation.

      Telltale Light Assembly

      • AIRBAG OFF Indicator Light

      • AIRBAG ON Indicator Light

      Informs the occupants of the airbag cut off switch cylinder sub-assembly status.

      Combination Meter Assembly

      SRS Warning Light

      Turns on to alert the driver when the airbag sensor assembly detects a malfunction in the airbag system.

      *: Models with curtain shield airbags

  2. SYSTEM CONTROL

    1. Airbag for Frontal Collision

      1. There are 4 airbags which deploy in the event of a frontal collision: the horn button assembly, instrument panel passenger airbag without door assembly and curtain shield airbag assemblies*. In addition, the front seat belt pretensioners contained in the front seat outer belt assemblies LH and RH are also activated.

        *: Models with curtain shield airbags

        Y148949E01

      2. 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.

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

      4. Frontal collision signals are produced based on the information from the airbag sensor assembly and front airbag sensor. Frontal collision signals are used to activate the front seat outer belt assemblies and to deploy all airbags except the front side airbags.

        Figure 1. Frontal Collision
        Y148950E01

    2. Airbag for Side/Rear Side Collision (Models with Front Side Airbags or Curtain Shield Airbags)

      1. There are 2 airbags which deploy in the event of a severe side collision: the front 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.

      2. For a side collision, if the side airbag sensor assembly detects an impact, it informs the airbag sensor assembly, and the airbag sensor assembly causes the front seat airbag assembly and curtain shield airbag assembly* to deploy simultaneously with the pretensioner (front seat outer belt assembly LH or RH).

        *: Models with curtain shield airbags

        Y148951E01

      3. The front seat airbag assemblies are deployed and the front seat belt pretensioner in the front seat outer belt assembly LH or RH is activated based on signals from the side airbag sensor assemblies, and the airbag sensor assembly.

        Figure 2. Side Collision
        Y148952E01

      4. For a rear side collision, if the side No. 2 airbag sensor assembly detects an impact, it informs the airbag sensor assembly via the side airbag sensor assembly and airbag sensor assembly causes the curtain shield airbag assembly to deploy.*

        *: Models with curtain shield airbags

        Y148953E01

      5. The curtain shield airbag assemblies are deployed based on signals from the side No. 2 airbag sensor assemblies or side airbag sensor assemblies, and the airbag sensor assembly.*

        *: Models with curtain shield airbags

        Figure 3. Side or Rear Side Collision
        Y148954E01

    3. Primary Check Illumination Control

      1. After the ignition switch is turned to 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 a malfunction is detected during the primary check, the SRS warning light remains on even after the 6 seconds have elapsed.

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

        Y104914E21

  3. DIAGNOSIS

    1. If the airbag sensor assembly detects a malfunction in the SRS airbag system, the airbag sensor assembly stores 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.