Lexus 2004 LS430 Owner's Manual page 396

STARTING AND DRIVING
CAUTION
D Do not rely solely on the pre-collision safety system
to avoid accidents. Your safe and attentive driving
practices are still the best way to avoid accidents and
you are always responsible for the operation of the
vehicle and the safety of your passengers. When
driving, always pay attention to the surrounding
conditions and the course you are driving.
D The pre-collision sensor's collision detection
performance is limited. The sensor is able to detect
a forward object within 10 degrees on either left or
right side. If it is out of the range, or if there is no or
weak millimeter wave reflection, the sensor could not
detect the object and the system does not work
properly.
D Even if the pre-collision safety is operative in an
unavoidable collision, unless the seat belts are worn
and the brake pedal is depressed, the pre-collision
seat belts and pre-collision brake assist system will
not work.
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NOTICE
Even if there is no object with which your vehicle may
collide, the pre-collision safety system may be
activated as follows:
D The pre-collision seat belts work to quickly draw
back the front seat belts by the retractors
(pre-collision seat belts).
D The pre-collision brake assist system works to apply
more powerful braking than normal braking.