AIR BAG SYSTEM [TWO-STEP DEPLOYMENT CONTROL SYSTEM (E)]

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Outline

• With the air bag system, the sophisticated airbag sensor (SAS) control module operates (deploys) the air bags according to the degree of impact during the collision to supplement the occupant protection function of the seat belts.

Warning

• The air bag system supplements the occupant protection function of the seat belts, however the intended effect of the air bag system cannot be obtained if the seat belts are not fastened correctly.

Function

• With the air bag system, the SAS control module calculates the degree of impact based on the collision detection signal from each of the following sensors, and operates (deploys) the required parts.

×: Collision detection

××: Operation (deployment)

—: No detection

Collision area	Sensor				Operation (deployment) part
Collision area	G sensor integrated into SAS control module	G sensor integrated into crash zone sensor	G sensor integrated into side air bag sensor	Pressure detection sensor integrated into pressure sensor	Driver-side air bag module	Passenger-side air bag module	Knee air bag module	Curtain air bag module (driver-side/passenger-side)	Side air bag module for front passenger (driver-side/passenger-side)	Far side air bag module (driver-side)	Side air bag module for rear passenger (driver-side/passenger-side)	Front pre-tensioner seat belt (driver-side/passenger-side)	Rear pre-tensioner seat belt (driver-side/passenger-side)
Collision from front of vehicle or frontal offset	×	—	—	—	—	—	—	—	—	—	—	—	—
	—	×	—	—	—	—	—	—	—	—	—	—	—
	×	×	—	—	××	××	××	××^{1, 2}	××^{1, 2}	—	—	××	××
Collision from side of vehicle	×	—	—	—	—	—	—	—	—	—	—	—	—
	—	—	×	—	—	—	—	—	—	—	—	—	—
	—	—	—	×	—	—	—	—	—	—	—	—	—
	×	—	×	—	—	—	—	××	××^*2	××	××^*2	××	××
	×	—	—	×	—	—	—	××	××^*2	××	××^*2	××	××
	×	—	×	×	—	—	—	××	××^*2	××	××^*2	××	××
Collision from rear of vehicle	×	—	—	—	—	—	—	—	—	—	—	—	—

*1 :Operates (deploys) by degree of impact during collision.

*2 :Operates (deploys) on the side the collision is detected.

With roll rate sensor

×: Collision detection

××: Operation (deployment)

—: No detection

Collision area	Sensor		Operation (deployment) part
Collision area	Roll rate sensor integrated into SAS control module	G sensor integrated into SAS control module	Driver-side air bag module	Passenger-side air bag module	Knee air bag module	Curtain air bag module (driver-side/passenger-side)	Side air bag module for front passenger (driver-side/passenger-side)	Far side air bag module (driver-side)	Side air bag module for rear passenger (driver-side/passenger-side)	Front pre-tensioner seat belt (driver-side/passenger-side)	Rear pre-tensioner seat belt (driver-side/passenger-side)
Vehicle is involved in rollover collision	×	—	—	—	—	—	—	—	—	—	—
	—	×	—	—	—	—	—	—	—	—	—
	×	×	—	—	—	××	—	—	—	××	××

Driver-side air bag deployment force switching function (two-step deployment)

• The driver-side air bag deployment force switching function switches the driver-side air bag deployment force by deploying inflators No.1 and 2 built into the driver-side air bag module simultaneously or only inflator No.1 according to the degree of impact from a frontal or frontal offset collision, the slide position of the driver's seat, and the front seat belt fastening status.

*1 :If the SAS control module deploys only inflator No.1, it deploys inflator No.2 soon afterwards to not leave it undeployed.

Collision impact

Driver's seat position

Front seat belt status

Driver-side air bag module

Air bag deployment force

Inflator No.1

Inflator No.2

Small

Position other than most forward position

Fastened

Deployment

—

Small

Large

Deployment

Deployment

Large

Small

Not fastened

Deployment

Deployment

Large

Large

Deployment

Deployment

Large

Small

Most forward position

Fastened

Deployment

—

Small

Large

Deployment

—

Small

Small

Not fastened

Deployment

—

Small

Large

Deployment

—

Small

Collision impact	Driver's seat position	Front seat belt status	Driver-side air bag module	Air bag deployment force
Small	Position other than most forward position	Fastened	Deployment	—	Small
Large	Deployment	Deployment	Large
Small	Not fastened	Deployment	Deployment	Large
Large	Deployment	Deployment	Large
Small	Most forward position	Fastened	Deployment	—	Small
Large	Deployment	—	Small
Small	Not fastened	Deployment	—	Small
Large	Deployment	—	Small

System conditions display function

• The SRS air bag system detects the condition of each part and sends a system condition signal from the SAS control module to the instrument cluster and indicator unit.

• The dash-electrical supply unit detects the driver’s buckle condition and sends a system signal to the instrument cluster.

• The instrument cluster and indicator unit indicate the following warning lights based on the system condition signal.

Warning light

Reference

Air bag/seat belt pre-tensioner system warning light

(See INSTRUMENT CLUSTER [(E)].)

(See WARNING/INDICATION/ALARM [TWO-STEP DEPLOYMENT CONTROL SYSTEM (E)].)

Seat belt warning light

(See INSTRUMENT CLUSTER [(E)].)

(See INDICATOR UNIT [(E)].)

Passenger air bag deactivation (PAD) indicator

(See PASSENGER AIR BAG DEACTIVATION (PAD) SYSTEM [TWO-STEP DEPLOYMENT CONTROL SYSTEM (E)].)

(See INDICATOR UNIT [(E)].)

Warning light	Reference
Air bag/seat belt pre-tensioner system warning light	(See INSTRUMENT CLUSTER [(E)].) (See WARNING/INDICATION/ALARM [TWO-STEP DEPLOYMENT CONTROL SYSTEM (E)].)
Seat belt warning light	(See INSTRUMENT CLUSTER [(E)].) (See INDICATOR UNIT [(E)].)
Passenger air bag deactivation (PAD) indicator	(See PASSENGER AIR BAG DEACTIVATION (PAD) SYSTEM [TWO-STEP DEPLOYMENT CONTROL SYSTEM (E)].) (See INDICATOR UNIT [(E)].)

Structure/Construction

Structural view

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System wiring diagram

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Operation

Collision from front of vehicle or frontal offset

1. When an impact from a frontal or frontal offset collision (1) is received, the G sensor built into the crash zone sensor and the G sensor (2) built into the SAS control module detect the impact and convert the impact into an electrical signal at the signal processing circuit (3).

2. The SAS control module calculates (6) the degree of impact using the determination and safing circuit (5) based on the electric signal (4) from each G sensor.

3. If the calculated degree of impact exceeds the previously set threshold, the SAS control module outputs (8) an operation (deployment) signal to each air bag module or pre-tensioner seat belt at the output control circuit (7).

4. Each air bag module or pre-tensioner seat belt operates (deploys) (9) based on the operation (deployment) signal from the SAS control module.

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Collision from side of vehicle

1. When an impact (1) from a lateral collision is received, the following sensors (2) detect the impact and convert the impact or the pressure into an electrical signal at the signal processing circuit (3).

― G sensor integrated into side air bag sensor

― G sensor integrated into SAS control module

― Pressure detection sensor integrated into pressure sensor

2. The SAS control module calculates (6) the degree of impact using the determination and safing circuit (5) based on the electric signal (4) from each G sensor or the pressure detection sensor.

4. Each air bag module or pre-tensioner seat belt operates (deploys) (9) based on the operation (deployment) signal from the SAS control module.

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Vehicle is involved in rollover collision

1. The following sensors integrated into the SAS control module (1) detect the various movements (2) of the vehicle while it is moving and converts them to electric signals.

― Low-G sensor in the SAS control module detects acceleration of vehicle in lateral and longitudinal direction

― Roll rate sensor in the SAS control module detects acceleration of vehicle in roll angle direction

2. The SAS control module calculates (4) the roll value using the determination and safing circuit (3) based on the electric signal from each sensor.

3. If the calculated degree of the roll angle exceeds the previously set threshold, the SAS control module outputs (6) an operation (deployment) signal to the curtain air bag module and pre-tensioner seat belt at the output control circuit (5).

4. The curtain air bag module and pre-tensioner seat belts operate (deploy) (7) based on the operation (deployment) signal from the SAS control module.

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