Lexus 2003 LS Owner's Manual page 274

STARTING AND DRIVING
You cannot set a desired speed if the master warning light
comes on, the warning tone sounds and the multi–information
display indicates a warning message such as "CRUISE NOT
AVAILABLE", "CLEAN RADAR SENSOR" or "CHECK
CRUISE SYSTEM". If any of the above messages appears on
the display, see "Vehicle–to–vehicle distance control mode
failure warning" on page 268.
If you turn off the main switch while the warning message is
displayed, the warning message turns off and the
multi–information display switches to another screen. If no
warning message appears on the display, when you turn the
main switch on again, the setting can be made.
You can change the dynamic laser cruise control screen to
another screen even while the warning message is displayed.
2 Cancelling the preset speed
You can cancel the preset speed by doing any of the following:
a. Pulling the control lever toward you, in the "CANCEL"
direction.
b. Depressing the brake pedal.
c. Pushing the main switch at the end of the cruise control
lever.
If cancelled by a. or b., the multi–information display shows
"RADAR READY" and the dynamic laser cruise control enters
the ready mode.
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If cancelled by c., the "CRUISE" indicator light goes off in the
instrument panel and the multi–information display shows
"CRUISE OFF". In this case, the preset speed data is cleared,
and you must set the speed from the beginning.
In the following cases, the preset speed automatically
cancels out. At this time, the multi–information display
shows "RADAR READY" and the dynamic laser cruise
control enters the ready mode.
a. The vehicle speed falls below about 40 km/h (25 mph). (40
km/h (25 mph) is designated as a cancel speed.)
b. The control lever is pressed downward in the "SET/COAST"
direction and held at less than 45 km/h (28 mph). (45 km/h (28
mph) is designated as a lower preset speed limit.)
CAUTION
In either a. or b., the warning tone reminds you that the
dynamic laser cruise control is cancelled and you must
apply the brakes to slow the vehicle.