1999 Lexus LS400 engine

STARTING AND DRIVING
297
CRUISE CONTROL
The cruise control allows you to cruise the vehicle
at a desired speed over 40 km/h (25 mph) with your
foot off the accelerator pedal.
Your cruising speed can be maintained although a slight
speed change may occur when driving up or down a
gradient, within the limits of engine performance. On
steeper hills, a great speed change will occur so it is
better to drive without the cruise control.
When the cruise control is on, the driving pattern of the
automatic transmission is fixed in the normal position,
regardless of the position of the selector switch.
CAUTION
To help maintain maximum control of your vehicle,
do not use the cruise control when driving in heavy
or varying traffic, or on slippery (rainy, icy or
snow±covered) or winding roads.
 Avoid vehicle speed increases when driving
downhill. If the vehicle speed is too fast in relation to
the cruise control set speed, cancel the cruise
control then downshift the transmission to use
engine braking to slow down.

STARTING AND DRIVING
300
Resetting to a faster speed
Press the control lever upward in the ºRES/ACCº
direction and hold it. Release the lever when the desired
speed is attained. While the lever is held upward, the
vehicle will gradually gain speed.
When the difference between the actual vehicle speed
and the set speed is less than 5 km/h (3 mph), the set
speed can be increased 1.6 km/h (1 mph) each time by
pressing the control lever upward in the ºRES/ACCº
direction quickly within 0.6 seconds.
However, a quicker way to reset is to accelerate the
vehicle and then press the control lever downward in the
ºSET/COASTº direction.
Resetting to a slower speed
Press the control lever downward in the ºSET/COASTº
direction and hold it. Release the lever when the desired
speed is attained. While the lever is held downward, the
vehicle speed will gradually decrease.
When the difference between the actual vehicle speed
and the set speed is less than 5 km/h (3 mph), the set
speed can be lowered 1.6 km/h (1 mph) each time by
pressing the control lever downward in the
ºSET/COASTº direction quickly within 0.6 seconds.
However, a quicker way to reset is to depress the brake
pedal and then press the control lever downward in the
ºSET/COASTº direction.
Even if you downshift the transmission from the ºDº
position to º4º with the cruise control on, engine braking
will not be applied because the cruise control is not
cancelled. To decrease the vehicle speed, reset to a
slower speed with the cruise control lever or depress the
brake pedal. If you use the brake pedal, cruise control
is cancelled.

STARTING AND DRIVING
305
31L052±1
When you turn the ignition switch on, this system
always turns on. Leave the system on during
ordinary driving so that it can operate when needed.
When traction control is applied, the slip indicator
light blinks.
You may hear a sound in the engine compartment for a
few seconds when the engine is started or just after the
vehicle is started. This means that the traction control
system is in the self ±check mode, and does not indicate
malfunction.
When the traction control system is operating, you may
feel vi bration of your vehicle, caused by operation of the
brakes. This indicates the system is functioning
properly. When getting the vehicle out of mud or new snow, etc.
the traction control system will help operate to prevent
the wheels from spinning.
To turn off the traction control system, see page 309.

STARTING AND DRIVING
307
VEHICLE SKID CONTROLSYSTEM
The vehicle skid control system helps to provide
comprehensive control of the systems such as an
anti±lock brake system, traction control, engine
control, electronically modulated air suspension,
etc. This system automatically controls the output
of the brakes or engine to help prevent the vehicle
from skidding when cornering on a slippery road
surface or abrupt steering wheel operation occurs.
31L052±1

STARTING AND DRIVING
308

Slip indicator light
If the vehicle is going to skid during driving, the slip
indicator light flashes and an alarm sounds.
The vehicle skid control activates when the vehicle
speed is about more than 15 km/h (9 mph).
Depressing the brake pedal repeatedly causes a small
noise from the engine compartment. This is a pump
pulsating sound of the brake system and it is not a
malfunction.
You may hear a sound in the engine compartment for a
few seconds when the engine is started or just after the
vehicle is started. This means that the vehicle skid
control is in the self±check mode and does not indicate
a malfunction.
31L017a

STARTING AND DRIVING
313
BRAKE SYSTEM
The tandem master cylinder brake system is a hydraulic
system with two separate sub±systems. If either
sub±system should fail, the other will still work.
However, the pedal will be harder to press, and your
stopping distance will be longer. Also, the brake system
warning light may come on.
CAUTION
Do not drive your vehicle with only a single brake
system. Have your brakes fixed immediately.
Brake booster
The brake booster uses engine vacuum to power±assist
the brakes. If the engine should quit while you are
driving, you can bring the vehicle to a stop with normal
pedal pressure. There is enough reserve vacuum for
one or two stops but no more!

STARTING AND DRIVING
314
CAUTION
Do not pump the brake pedal if the engine stalls.
Each push on the pedal uses up your vacuum
reserve.
 Even if the power assist is completely lost, the brakes
will still work. But you will have to push the pedal
hard ± much harder than normal. And your braking
distance will be longer.

STARTING AND DRIVING
315
Anti±lock brake system
The anti±lock brake system is designed to
automatically help prevent lock±up of the wheels
during a sudden brake or braking on slippery road
surfaces. This assists in providing directional
stability and steering performance of the vehicle
under these circumstances.
The anti±lock brake 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).
You may hear a sound in the engine compartment for a
few seconds when the engine is started or just after the
vehicle is started. This means that the anti±lock brake
system is in the self±check mode, and does not indicate
a malfunction.
Effective way to press the ABS brake pedal: When the
anti±lock brake system function is in action, you may feel the
brake pedal pulsating and hear a noise. In this situation, to
let the anti±lock brake system work for you, just hold the
brake pedal down more firmly. Do not pump the brake in a
panic stop. Pumping the brake pedal makes the stopping
distance longer.