Lexus 2004 LS430 Owner's Manual page 199

The SRS front passenger airbag will not activate if there is no
passenger sitting in the front passenger seat. However, the
front passenger airbag may deploy if luggage is put in the seat,
or the seat belt is buckled up, regardless of the presence of an
occupant in the seat.
Always wear your seat belt properly.
Your vehicle is equipped with a crash sensing and diagnostic
module, which will record the use of the seat belt restraint
system by the driver and front passenger when the SRS front
airbags are inflated.
OCCUPANT RESTRAINT SYSTEMS
CAUTION
D The SRS front airbag system is designed only as a
supplement to the primary protection of the driver
and front passenger seat belt systems. The driver
and front passenger can be killed or seriously injured
by the inflating airbags if they do not wear the
available seat belts properly. During sudden braking
just before a collision, an unrestrained driver or front
passenger can move forward into direct contact with
or close proximity to the airbag which may then
deploy during the collision. To ensure maximum
protection in an accident, the driver and all
passengers in the vehicle must wear their seat belts
properly. Wearing a seat belt properly during an
accident reduces the chances of death or serious
injury or being thrown out of the vehicle.
instructions and precautions concerning the seat
belt system, see "Seat belts" on page 167.
For
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