Toyota Lexusc Owner's Handbook Manual page 502

(b) Setting the desired speed
With automatic transmission (standard type) —
The transmission must be in "D" before you set the cruise
control speed in the conventional cruise control mode.
With automatic transmission (multi-mode type) —
The transmission must be in "D", "5" (fifth range) or "4" (fourth
range) before you set the cruise control speed in the
conventional cruise control mode.
Bring your vehicle to the desired speed, push the lever down
in the "- SET" direction and release it. This sets the vehicle at
that speed and the display shows the preset speed. You can
now take your foot off the accelerator pedal.
If you need to accelerate — for example, when passing —
depress the accelerator pedal enough for the vehicle to exceed
the preset speed. When you release the accelerator pedal, the
vehicle will return to the speed set prior to acceleration.
STARTING AND DRIVING
You cannot set a desired speed if the master warning light
comes on, the alarm sounds and the display indicates the
warning code "E3". If this code appears on the display, see "(g)
Conventional cruise control mode failure warning" on page
485.
(c) Cancelling the preset speed
You can cancel the preset speed by doing any of the following:
a. Pulling the lever in the "CANCEL" direction.
b. Depressing the brake pedal.
c. Pressing the "ON-OFF" button.
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 slip indicator light blinks and an alarm sounds. (This
occurs when the vehicle is about to skid.)
If cancelled by a. or b., the preset speed data is cleared and you
must set the speed from the beginning.
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.
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