System Description

SYSTEM DIAGRAM 

Courtesy of NISSAN NORTH AMERICA, INC.

INPUT SIGNAL AND OUTLET SIGNAL 

Major signal transmission between each unit via communication lines is shown in the following table:

DESCRIPTION 

Supplemental Restraint System (SRS) activates the air bag module and seat belt pre-tensioner when it detects a frontal collision or a side collision that is more than the specified limit. Together with other safety devices, it reduces the impact that occupant receives when vehicle collision occurs. Air bag diagnosis sensor unit supplies power supply to air bag module and pre-tensioner seat belt when deceleration that is more than the specified limit is detected by G sensor in air bag diagnosis sensor unit, crash zone sensor, satellite sensor, or front door satellite sensor. Air bag module is composed of electric igniter (squib), filter, pyrotechnic material, and gas generating material. When air bag module receives a signal from air bag diagnosis sensor unit, air bag module ignites pyrotechnic material using electric igniter (squib) so that gas generating material generates high temperature nitrogen gas. The gas through filter activates air bag. At the same time, pre-tensioner seat belt receives power supply from air bag diagnosis sensor unit, gas generator is activated, and then gas is generated. Balls in pipe are moved according to generated gas pressure and strike pinion gear on ELR shaft. ELR shaft rotates and retracts seat belt.

AIR BAG DIAGNOSIS SENSOR UNIT FUNCTIONS 

Air bag diagnosis sensor unit has the following functions:

• Detects a collision and supplies the energy for deploying air bag and seat belt pre-tensioner.
• Detects and records electrical malfunction in air bag system and seat belt pre-tensioner system, and illuminated air bag warning lamp.
• Detects and records the deployment of air bag and seat belt pre-tensioner and turns ON the air bag warning lamp.
• Indicates the malfunction record via CONSULT.
• Suppresses the deployment of passenger air bag when passenger seat is empty or occupied by child or child-seat.
• When passenger seat is occupied by child or child seat, turns ON passenger air bag OFF indicator.
• When judges that passenger seat is occupied by a adult or a child and passenger seat belt is not fasten, turns ON seat belt warning lamp. Further information for the seat belt warning system.

COLLISION MODES 

The operation of SRS is different depending on the collision modes applications. For example, the driver air bag module, passenger air bag module, and seat belt pre-tensioner are activated in a frontal collision or side collision.

SRS configurations that are activated for the following collision modes:

x: Apply, -: Not apply