Lexus GS430 User Manual page 183

Seat belt pretensioners
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Both front seats and the two outboard rear seats are
equipped with seat belt pretensioners and are designed to
be activated in response to a severe frontal impact.
When the sensor detects a severe frontal impact, the seat belts
are quickly drawn back by the retractor so that the belts snugly
restrain the occupants.
The front passenger seat belt pretensioner will not activate if
there is no passenger sitting in the front passenger seat.
However, the front passenger seat belt pretensioner may
activate if luggage is put in the seat, or the seat belt is buckled
up regardless of the presence of the occupant in the seat.
The outboard rear seat belt pretensioners are activated even
with no passengers in the outboard rear seats.
The seat belt pretensioners and SRS airbags may not operate
together in all collisions.
OCCUPANT RESTRAINT SYSTEMS
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" 1 Front airbag sensors
2 Occupant detection sensor
3 Front passenger's seat belt buckle switch
4 Front seat belt pretensioner assembly
5 SRS warning light
6 Rear seat belt pretensioner assembly
7 Airbag sensor assembly
The seat belt pretensioner system consists mainly of the
above components, and their locations are shown in the
illustration.
The seat belt pretensioners are controlled by the airbag sensor
assembly. The airbag sensor assembly consists of a safing
sensor and airbag sensor.
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