Lexus GS430 User Manual page 461

If any of the following conditions occur, this indicates a
malfunction somewhere in the components monitored by
the warning light system. Contact your Lexus dealer as
soon as possible to service the vehicle.
D The light does not come on when engine switch is selected
in "IG−ON" mode.
D The light remains on after the engine is started (GS430), or
remains on a few seconds after the engine switch is
selected in "IG−ON" mode (GS300).
D The light comes on while you are driving.
A warning light turning on briefly during operation does not
indicate a problem.
CAUTION
If the "ABS" warning light remains on together with the
brake system warning light (red), immediately stop your
vehicle at a safe place and contact your Lexus dealer.
In this case, not only the anti−lock brake system will fail
but also the vehicle will become extremely unstable
during braking.
GS430 only—Either of the following conditions may
occur, but does not indicate a malfunction:
D The light may stay on for about 60 seconds after the engine
is started. It is normal if it turns off after a while.
D Depressing the brake pedal repeatedly may turn on the
light. It is normal if it turns off after a few seconds.
STARTING AND DRIVING
Drum−in−disc type parking brake system
Your vehicle has a drum−in−disc type parking brake system.
This type of brake system needs bedding−down of the brake
shoes periodically or whenever the parking brake shoes
and/or drums are replaced.
Have your Lexus dealer perform the bedding−down.
Brake assist system
When you slam the brakes on, the brake assist system
judges as an emergency stop and provides more powerful
braking for a driver who cannot hold down the brake pedal
firmly.
When you slam the brakes on, more powerful braking will be
applied. At this time, you may hear a sound in the engine
compartment and feel the vibrations of the brake pedal. This
does not indicate a malfunction.
The brake assist system becomes operative after the vehicle
has accelerated to a speed in excess of approximately 10 km/h
(6 mph). It stops operating when the vehicle decelerates to a
speed below approximately 5 km/h (3 mph).
The brake assist system may not work for about 60 seconds
after the engine is started.
For an explanation of this system's warning light, see "ABS"
warning light on page 80 or 436.
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