Purpose
The pre-tensioner seat belt retracts and tightens the seat belt webbing to protect the front passengers during a collision.
Function
The pre-tensioner seat belts operate (deploy) based on the operation signal from the SAS control module to instantly retract and tighten the belt webbing, restraining the driver and front passenger.

Construction
The pre-tensioner seat belt is installed to the front seat belt retractor.
The pre-tensioner seat belt consists of the following parts shown in the figure:

Operation
Normal operation (pre-tensioner non-operation)
Normally, there is a gap between the locking base and the ring gear.
The ring gear rotates in conjunction with the withdrawal and retraction of the front seat belts, however, in the pre-tensioner part it is kept separated.

Pre-tensioner activation
1. The gas generator produces gas when it receives an operation signal from the SAS control module.
2. The ball in the cylinder is pressed by the gas pressure and the ring gear is removed from its securement.
3. The ring gear is engaged with the locking base and the force of the ball being pressed out is transmitted to the retraction shaft.
4. The front seat belt is retracted in conjunction with the rotation of the retraction shaft.

Fail-safe
Function not equipped.
Passenger Side Air Bag Module [Two Step Deployment Control System]
Pre Tensioner Seat Belt [Two Step Deployment Control System]Propeller Shaft On Vehicle Inspection
Joint Area Excessive Play Inspection
1. Shake the universal joint by hand and verify that there is no excessive play.
2. If there is any excessive play, replace the propeller shaft..
Propeller Shaft Runout Inspection
CAUTION:
Do not rotate the propeller shaft using engine force wh ...
Auto Light Sensor
Purpose
The auto light sensor detects the illumination level above and in front of
the vehicle and outputs it to the front body control module (FBCM).
Function
The auto-light sensor uses the upward illumination level sensor to detect
the illumination level above the vehicle ...
Crash Zone Sensor Removal/Installation [Standard Deployment Control System]
WARNING:
Handling the crash zone sensor improperly can accidentally deploy the air
bags and pre-tensioner seat belts, which may seriously injure you. Read the
air bag system service warnings and cautions before handling the crash zone
sensor..
1. Switch the ignition to off.
...