AIRBAG SYSTEM

FUNCTION OF MAIN COMPONENTS

The main components in the airbag system have the following functions:

Components		Outline
Airbag ECU Assembly		In the event of a frontal collision, the airbag ECU assembly receives signals from either of the front airbag sensors. The airbag ECU assembly receives the signal via its judgment circuit and also receives another signal from the safing sensor built into the airbag ECU assembly. After receiving a signal from at least one of the front airbag sensors and the safing sensor, the airbag ECU assembly determines whether the driver airbag, front passenger airbag, driver knee airbag, front passenger seat cushion airbag, curtain shield airbags, side airbags, front seat belt pretensioners and rear seat belt pretensioners*1 should be deployed. The airbag ECU assembly also diagnosis system malfunctions. In the event of a side or rear side collision, the airbag ECU assembly receives signals from the door side airbag sensor or side airbag sensor assembly. The airbag ECU assembly receives the signal via its judgment circuit and also receives another signal from the safing sensor built into the airbag ECU assembly. After receiving a signal from at least one of the side sensors and the safing sensor, the airbag ECU assembly determines whether the front seat airbag assemblies, curtain shield airbag assemblies and seat belt pretensioner should be deployed. The airbag ECU assembly also diagnosis system malfunctions. The airbag ECU assembly sends an airbag deployment signal to the ECM through the Controller Area Network (CAN) to operate fuel pump control.
Horn Button Assembly		The airbags are used as supplements to the seat belts to help reduce impact to the occupants.
Instrument Panel Passenger Airbag without Door Assembly
No. 1 Instrument Panel Lower Airbag Assembly
Front Seat Airbag Assembly LH/RH
Front Seat Cushion Airbag Assembly RH
Curtain Shield Airbag Assembly 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.
Door Side Airbag Sensor 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 Airbag Sensor Assembly LH/RH
Front Seat Outer Belt Assembly LH/RH		The front seat outer belt assemblies are used to help reduce impact to the occupants.
Rear No. 1 Seat Outer Belt Assembly LH/RH*1		The rear No. 1 seat 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.
Hybrid Vehicle Control ECU		The hybrid vehicle control ECU receives an airbag deployment signal from the airbag ECU assembly during a frontal, side or rear side collision. In the event of a collision, the hybrid vehicle control ECU 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*2		The airbag cut off switch cylinder sub-assembly suspends the instrument panel passenger airbag without door assembly operation.
Air Conditioning Control Assembly AIRBAG ON/OFF Indicator Light2, 3		The AIRBAG ON/OFF indicator lights inform the occupants of the airbag cut off switch cylinder sub-assembly status.*2
		The AIRBAG ON/OFF indicator lights inform the driver whether the occupant detection ECU puts the instrument panel passenger airbag without door assembly, front seat cushon airbag assembly, front seat airbag assembly RH and front seat outer belt assembly RH into an active state or inactive state.*3
Combination Meter Assembly	SRS Airbag Warning Light	Turns on to alert the driver when the airbag ECU assembly detects a malfunction in the airbag system.
	Multi-information Display	Displays the warning message to inform the driver of a malfunction in the system.
	Master Warning Light	Turns on to alert the driver when the airbag ECU assembly detects a malfunction in the system.
	Multi Buzzer	Sounds to warn the driver of a malfunction in the system.

*1: Models with rear pretensioner squib
*2: Models with airbag cut off switch cylinder
*3: Destination package for Korea

SYSTEM CONTROL
1. Airbag for Frontal Collision
  1. There are 8 airbags which deploy in the event of a frontal collision: the horn button assembly, instrument panel passenger airbag without door assembly, No. 1 instrument panel lower airbag assembly, front seat cushion airbag assembly RH, front seat airbag assemblies 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, the front pretensioners contained in the front seat outer belt assemblies LH and RH, and rear pretensioners contained in the rear No. 1 seat outer belt assembly LH and RH* are also activated.
    
    *: Models with rear pretensioner squib
  2. The airbag ECU assembly detects the information indicated 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 ECU assembly. The airbag ECU assembly causes the horn button assembly, instrument panel passenger airbag without door assembly, No. 1 instrument panel lower airbag assembly, front seat cushion airbag assembly RH, front seat airbag assemblies and curtain shield airbag assemblies to deploy. Meanwhile, the airbag ECU assembly activates the seat belt pretensioners for the driver, front passenger and rear passengers.
  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 ECU 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 ECU assembly and front airbag sensors. Frontal collision signals are used to deploy the airbags and activate the pretensioners as indicated in the table below.
2. Airbag for Side/Rear Side Collision
  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 door side airbag sensor detects an impact, it informs the airbag ECU assembly, and the airbag ECU assembly causes the front seat airbag assembly and curtain shield airbag assembly to deploy simultaneously, and activates the front seat outer belt assembly and rear No. 1 seat belt assembly*.
    
    *: Models with rear pretensioner squib
  3. The front seat airbag assembly and curtain shield airbag assembly are deployed and the front pretensioner in the front seat outer belt assembly LH or RH and rear No. 1 seat outer belt assembly LH or RH* is activated based on signals from the door side airbag sensors and airbag ECU assembly.
    
    *: Models with rear pretensioner squib
  4. For a rear side collision, if the side airbag sensor assembly detects an impact, it informs the airbag ECU assembly and the airbag ECU assembly causes the curtain shield airbag assembly LH or RH and rear No. 1 seat outer belt assembly RH or LH* to be deployed.
    
    *: Models with rear pretensioner squib
  5. The curtain shield airbag assembly is deployed based on signals from the side airbag sensor assemblies or the door side airbag sensors and the airbag ECU assembly.
3. Airbag for Roll Over (Destination Package for Korea)
  1. If the vehicle is tilted and rolls over, the airbag ECU assembly activates the seat belt pretensioners for the driver and front passenger and left and right curtain shield airbags based on signals that show the vehicle's roll angle and rotation speed.
  2. If the vehicle rolls over in a side collision, the airbag ECU assembly causes the front seat airbag assembly and curtain shield airbag assembly to deploy based on signals from the side airbag sensor assembly and door side airbag sensor. Meanwhile, the airbag ECU assembly activates the seat belt pretensioners for the driver and front passenger and the curtain shield airbag on the opposite side of the collision, based on lateral deceleration and rotation speed signals.
4. Primary Check Illumination Control
  1. After the power switch is turned on (IG), the airbag ECU assembly illuminates the SRS airbag 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 ECU assembly is performed. If a malfunction is detected during the primary check, the SRS airbag warning light remains on even after the 6 seconds have elapsed.
  2. After the power switch is turned on (IG), the airbag ECU assembly operates the passenger AIRBAG ON/OFF indicator lights as shown below to check for an open in the indicator light circuits.
DIAGNOSIS
1. If the airbag ECU assembly detects a malfunction in the SRS airbag system, the airbag ECU assembly stores the malfunction data in memory in addition to illuminating the SRS airbag warning light.
2. The airbag ECU assembly outputs malfunction data and 5-digit Diagnostic Trouble Codes (DTCs) to the Global TechStream (GTS).
3. The 5-digit DTCs can be read after connecting the Global TechStream (GTS) to the DLC3. For details, refer to the Repair Manual.
4. If the SRS airbags deploy, the airbag ECU assembly will turn on the SRS warning light. However, unlike the ordinary diagnosis function, a DTC will not be stored. The SRS warning light cannot be manually turned off. It is necessary to replace the airbag ECU assembly with a new one.