AIRBAG SYSTEM

FUNCTION OF MAIN COMPONENTS

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

Components		Function
Driver Airbag (Horn Button Assembly)		Used as supplements to the seat belts to help reduce impact to the occupants.
Front Passenger Airbag (Instrument Panel Passenger Airbag without Door Assembly)
Driver Knee Airbag (Lower No. 1 Instrument Panel Airbag Assembly)
Front Passenger Knee Airbag (Lower No. 2 Instrument Panel Airbag Assembly)
Driver Side Airbag (Front Seat Airbag Assembly LH)
Front Passenger Side Airbag (Front Seat Airbag Assembly RH)
Rear Outer Passenger Side Airbag LH (Rear Seat Airbag Assembly LH)
Rear Outer Passenger Side Airbag RH (Rear Seat Airbag Assembly RH)
Curtain Shield Airbag Assembly LH
Curtain Shield Airbag Assembly RH
Rear Seat Cushion Airbag Assembly LH*1		Used as a supplement to the seat belt to help suppress the occupant's forward movement.
Rear Seat Cushion Airbag Assembly RH*1
Front Seat Outer Belt Assembly LH Seat Belt Pretensioner		Used to help reduce impact to the occupants.
Front Seat Outer Belt Assembly RH Seat Belt Pretensioner
Rear No. 1 Seat Outer Belt Assembly LH Seat Belt Pretensioner
Rear No. 1 Seat Outer Belt Assembly RH Seat Belt Pretensioner
Spiral Cable with Sensor Sub-assembly		Transmits ignition signals from the airbag ECU assembly to the SRS driver airbag.
Seat Position Airbag Sensor		Detects the slide position of the driver seat.
Front Airbag Sensor LH		Based on the deceleration of the vehicle during a frontal collision, distortion is created in the sensor and is converted into an electrical signal.
Front Airbag Sensor RH
Door Side Airbag Sensor LH		Detects deformation of the front doors during a side collision using the pressure sensor and sends signals for the airbag ECU assembly to determine if deployment of SRS components is necessary.
Door Side Airbag Sensor RH
Side Airbag Sensor Assembly LH		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 RH
No. 2 Side Airbag Sensor Assembly LH
No. 2 Side Airbag Sensor Assembly RH
Rear Airbag Sensor LH
Rear Airbag Sensor RH
Yawrate Sensor		Sends yawrate sensor signals to the airbag ECU assembly via CAN communication.
Steering Sensor		Sends steering angle signals to the airbag ECU assembly via CAN communication.
Front Occupant Classification Sensor*2		The output values of this sensor, which vary in accordance with the distortion that acts on the brackets, are output to the occupant detection ECU.
Rear Occupant Classification Sensor*2
Airbag Cut Off Switch Cylinder Sub-assembly*3		Suspends the SRS front passenger airbag operation.
Driver Seat Belt Buckle Switch (Front Seat Inner Belt Assembly LH)		Detects if the driver seat belt is fastened.
Front Passenger Seat Belt Buckle Switch (Front Seat Inner Belt Assembly RH)		Detects if the front passenger seat belt is fastened.
Rear Outer Passenger Seat Belt Buckle Switch LH (Rear Seat Belt Assembly Inner LH)		Detects if the rear outer passenger seat belt LH is fastened.
Rear Outer Passenger Seat Belt Buckle Switch RH (Rear Seat Belt Assembly Inner)		Detects if the rear outer passenger seat belt RH is fastened.
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 SRS driver airbag, SRS front passenger airbag, SRS driver knee airbag, SRS front passenger knee airbag, SRS rear seat cushion airbags*1, SRS curtain shield airbag assemblies and front and rear seat belt pretensioners should be deployed. The airbag ECU assembly also diagnoses system malfunctions. In the event of a side or rear side collision, the airbag ECU assembly receives signals from the door side airbag sensor, side airbag sensor assembly, No. 2 side airbag sensor assembly or rear airbag sensor. 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 SRS driver, front passenger and rear outer passengers side airbags, SRS curtain shield airbag assemblies and seat belt pretensioners should be deployed. The airbag ECU assembly also diagnoses system malfunctions.
Occupant Detection ECU*2		Judges whether the front passenger seat is occupied based on signals from the 2 occupant classification sensors and the front passenger seat belt buckle switch.
Pedestrian Detection ECU Assembly		Sends the operation status of the pop up hood system to the airbag ECU assembly via CAN communication.
ECM		Sends shift position signals, engine speed signals and the operation status of the engine control system to the airbag ECU assembly via CAN communication.
Skid Control ECU Assembly*4		Sends vehicle speed signals, brake pedal operation signals and the operation status of the brake control system to the airbag ECU assembly via CAN communication.
Brake Actuator Assembly*5 Skid Control ECU
Combination Meter Assembly	SRS Warning Indicator	Turns on to alert the driver when the airbag ECU assembly detects a malfunction in the SRS airbag system.
	Multi-information Display	Displays a warning message to inform the driver of a malfunction in the SRS airbag system.
	Master Warning Indicator	Turns on to alert the driver when the airbag ECU assembly detects a malfunction in the SRS airbag system.
	Buzzer	Sounds to warn the driver of a malfunction in the SRS airbag system.
Telltale Lamp Assembly2, 3	AIRBAG ON Indicator Light	Turns on to inform the driver when the occupant detection ECU has put the SRS front passenger airbag and SRS front passenger knee airbag into an active state.
Telltale Lamp Assembly2, 3	AIRBAG OFF Indicator Light	Turns on to inform the driver when the occupant detection ECU has put the SRS front passenger airbag and SRS front passenger knee airbag into an inactive state. Turns on to alert the driver when the airbag ECU assembly detects a malfunction in the occupant classification system.
Central Gateway ECU (Network Gateway ECU)		Relays the signal between the CAN communication lines.
DLC3		The Global TechStream (GTS) can be connected to read the Diagnostic Trouble Codes (DTCs) of malfunctions.

*1: Models with rear seat cushion airbag

*2: Models for Korea

*3: Models with airbag cut off switch cylinder

*4: Models with electronically controlled brake system

*5: Models with vacuum brake booster

OPERATING CONDITION
1. Frontal Collision
  1. Deceleration sensors used for the SRS airbag system are installed on various parts on the vehicle and calculate the deceleration (or acceleration) rate of each part during a collision.
  2. Depending on the situation, the airbag ECU assembly sends a deployment signal to each SRS airbag based on the information from each sensor.
  3. 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 SRS airbags and activate the seat belt pretensioners as indicated in the table below.
  4. If the severity of the collision is particularly high, the SRS curtain shield airbag assemblies LH and RH are deployed.
2. Side Collision
  1. The SRS side airbag, SRS rear outer passenger side airbag and SRS curtain shield airbag assembly on the side of the collision are deployed and the front and rear seat belt pretensioners on the side of the collision are activated based on signals from the door side airbag sensor, side airbag sensor assembly, No. 2 side airbag sensor assembly and airbag ECU assembly.
  2. If the severity of the collision is particularly high, the SRS curtain shield airbag assembly on the side opposite the collision is deployed* and the front and rear seat belt pretensioners on the side opposite the collision are activated.
    
    *: Models for Korea
3. Rear Side Collision
  1. The SRS rear outer passenger side airbag and SRS curtain shield airbag assembly on the side of the collision are deployed and the rear seat belt pretensioner on the side of the collision is activated based on signals from the rear airbag sensor, No. 2 side airbag sensor assembly and airbag ECU assembly.
  2. If the severity of the collision is particularly high, SRS curtain shield airbag assembly on the side opposite the collision is deployed* and rear seat belt pretensioner on the side opposite the collision is activated.
    
    *: Models for Korea
4. Roll Over (Models for Korea)
  1. The SRS curtain shield airbag assemblies LH and RH are deployed and the front and rear seat belt pretensioners are activated based on signals that show the vehicle's roll angle and rotation speed.

SYSTEM CONTROL

Frontal Collision

There are 4 or 6* SRS airbags which deploy in the event of a frontal collision: the SRS driver airbag, SRS front passenger airbag, SRS driver knee airbag, SRS front passenger knee airbag, SRS rear seat cushion airbag LH* and SRS rear seat cushion airbag RH*. These SRS airbags deploy simultaneously. The SRS driver airbag and SRS front passenger airbag use dual-stage control. In addition, the seat belt pretensioners contained in the front seat outer belt assemblies LH and RH and the rear No. 1 seat outer belt assemblies LH and RH are also activated.
The airbag ECU assembly detects the information in the table below from various sources in order to activate the dual-stage control.
For a frontal collision, if a front airbag sensor detects an impact, it informs the airbag ECU assembly. The airbag ECU assembly causes the SRS driver airbag, SRS front passenger airbag, SRS driver knee airbag, SRS front passenger knee airbag, SRS rear seat cushion airbag LH* and SRS rear seat cushion airbag RH* to deploy. Additionally, the airbag ECU assembly activates the front and rear seat belt pretensioners.

If the severity of the collision is particularly high, the SRS curtain shield airbag assemblies LH and RH are deployed.

*: Models with rear seat cushion airbag

Airbag	Information	Source
Driver	Extent of Impact	Front Airbag Sensor LH or RH Airbag ECU Assembly
	Driver Seat Position	Seat Position Airbag Sensor
	Seat Belt Condition	Driver Seat Belt Buckle Switch (Non-contact Type)
Front Passenger	Extent of Impact	Front Airbag Sensor LH or RH Airbag ECU Assembly
	Occupant Detection*1	2 Occupant Classification Sensors (Connected to the airbag ECU assembly through the occupant detection ECU.)
	Airbag Cut Off Switch Cylinder Status*2	Airbag Cut Off Switch Cylinder Sub-assembly
	Seat Belt Condition	Front Passenger Seat Belt Buckle Switch (Non-contact Type)(Connected to the airbag ECU assembly through the occupant detection ECU.*1)

*1: Models for Korea

*2: Models with airbag cut off switch cylinder

Side Collision
1. There are 3 SRS airbags which deploy in the event of a side collision: the SRS side airbag, SRS rear outer passenger side airbag and SRS curtain shield airbag assembly on the side of the collision. These SRS airbags deploy simultaneously. Additionally, at the same time, the front and rear seat belt pretensioners on the side of the collision are also activated.
2. For a side collision, if the door side airbag sensor, side airbag sensor assembly and No. 2 side airbag sensor assembly detect an impact, it informs the airbag ECU assembly. The airbag ECU assembly causes the SRS side airbag, SRS rear outer passenger side airbag and SRS curtain shield airbag assembly on the side of the collision to deploy simultaneously, and activates the front and rear seat belt pretensioners on the side of the collision.
3. If the severity of the collision is particularly high, the SRS curtain shield airbag assembly on the side opposite the collision is deployed* and the front and rear seat belt pretensioners on the side opposite the collision are activated.
  - *: Models for Korea
Rear Side Collision
1. The SRS rear outer passenger side airbag and SRS curtain shield airbag assembly on the side of the collision deploy in the event of a rear side collision. Additionally, at the same time, the rear seat belt pretensioner on the side of the collision is also activated.
2. For a rear side collision, if the rear airbag sensor or No. 2 side airbag sensor assembly detects an impact, it informs the airbag ECU assembly and the airbag ECU assembly causes the SRS rear outer passenger side airbag and SRS curtain shield airbag assembly on the side of the collision to deploy simultaneously, and activates the rear seat belt pretensioner on the side of the collision.
3. If the severity of the collision is particularly high, the SRS curtain shield airbag assembly on the side opposite the collision is deployed* and the rear seat belt pretensioner on the side opposite the collision is activated.
  - *: Models for Korea
Roll Over (Models for Korea)
1. If the vehicle is tilted and rolls over, the airbag ECU assembly activates the SRS curtain shield airbag assemblies LH and RH and seat belt pretensioners for the driver, front passenger and rear passengers 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 SRS side airbag, SRS rear outer passenger side airbag and SRS curtain shield airbag assembly on the side of the collision to deploy simultaneously, and activates the front and rear seat belt pretensioners on the side of the collision based on signals from the door side airbag sensor, side airbag sensor assembly and No. 2 side airbag sensor assembly. Meanwhile, the airbag ECU assembly activates the SRS curtain shield airbag assembly on the side opposite the collision and the front and rear seat belt pretensioners on the side opposite the collision, based on lateral deceleration and rotation speed signals.
Primary Check Illumination Control
1. After the engine switch is turned on (IG), the airbag ECU assembly illuminates the SRS warning indicator in the combination meter assembly for approximately 6 seconds and conducts the primary check. During the primary check, the ignition of SRS airbags is prohibited and a diagnosis of the airbag ECU assembly is performed. If a malfunction is detected during the primary check, the SRS warning indicator will remain on even after 6 seconds have elapsed.
2. After the engine switch is turned on (IG), the airbag ECU assembly operates the front passenger airbag ON/OFF indicator lights as shown below to check for an open in the indicator light circuits.
  
  Figure 1. Except Models for Korea
  
  Figure 2. Models for Korea

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 warning indicator.
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 by 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 indicator. However, unlike an ordinary malfunction, a DTC will not be stored. The SRS warning indicator cannot be manually turned off. It is necessary to replace the airbag ECU assembly with a new one.