Lexus GS430 User Manual page 444

The hill−start assist control system will operate for 5
seconds maximally when all of the following conditions
apply.
D When the selector lever is in "D" or "S" position
D When the brake pedal is not depressed
The system is designed to operate when the vehicle is starting
on an uphill slope; therefore, if the selector lever is in "P" or "N",
it will not operate. It will not operate either if the vehicle starts
to move in reverse on a slope with the selector lever in "R".
When the hill−start assist control system is operating, you may
hear a sound. This indicates the hill−start assist control is
operating normally and does not indicate a malfunction.
G31038
"Slip indicator light
When the hill−start assist control system is operating, the slip
indicator light flashes. At the same time, the stop lights and
high mounted stoplight are lit.
STARTING AND DRIVING
GS430—The slip indicator light comes on when the engine
switch is selected in "IG−ON" mode. The light goes off when
the engine is started.
GS300—The slip indicator light comes on for a few seconds
when the engine switch is selected in "IG−ON" mode.
If the indicator light does not come on when the engine switch
is selected in "IG−ON" mode, contact your Lexus dealer.
Keep the following in mind when driving:
D The hill−start assist control system operates for 5 seconds
maximally. If both the brake and accelerator pedals remain
undepressed for longer than 5 seconds, the buzzer will
sound at more frequent intervals and the system will
gradually stop operating.
D The hill−start assist control system is not designed for
stopping the vehicle on an uphill slope. When stopping the
vehicle, be sure to depress the brake pedal.
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