Lexus 2003 LS Owner's Manual page 287

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 "CHECK
CRUISE SYSTEM". If this messages appears on the display,
see "Conventional cruise control mode failure warning" on
page 275.
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. When
you turn the main switch on again, the warning message
comes back on the display. If no warning message appears on
the display, 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 in the "CANCEL" direction.
b. Depressing the brake pedal.
c. Turning off the main switch.
If cancelled by a. or b., the multi–information displays shows
nothing and the conventional cruise control enters the ready
mode.
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.
STARTING AND DRIVING
In the following cases, the preset speed automatically
cancels out:
a. The vehicle speed falls below about 40km/h (25 mph).
b. If the vehicle speed drops 16 km/h (10 mph) below the
preset speed, the preset speed will also automatically be
cancelled.
c. The control lever is pressed downward in the "SET/COAST"
direction and held at less than about 45 km/h (28 mph). (45
km/h (28 mph) is designated as a lower preset speed limit .)
d. The slip indicator light blinks and a warning tone sounds.
(This occurs when the vehicle is about to skid.)
If the vehicle speed falls below about 40 km/h (25 mph), the
preset speed data is cleared and you must set the speed from
the beginning.
If cancelled by the above cases, the multi–information displays
shows nothing and the conventional cruise control enters the
ready mode.
If the preset speed automatically cancels out for other than the
above reasons, do not operate the cruise control. Although it
is no problem to continue driving, have your vehicle checked
by your Lexus dealer at the earliest opportunity.
273