1998 Lexus LS400 lexus LS400 1998 Engine / LEXUS 1998 LS400 OWNER'S MANUAL (OM50498U)

STARTING AND DRIVING
170If the vehicle speed falls below about 40 km/h (25 mph), the preset
speed will be automatically cancelled.
If the vehicle speed drops 16 km/h (10 mph) below the preset speed,
the preset speed will also automatically be cancelled.
If the preset speed automatically cancels out for other than these
reasons, have your vehicle checked by your Lexus dealer at the
earliest opportunity.
Resetting to a faster speed
Press the control lever upward in the ”RES/ACC” 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
”RES/ACC” 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 ”SET/COAST” direction.
Resetting to a slower speed
Press the control lever downward in the ”SET/COAST” 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 ”SET/COAST” 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 ”SET/COAST”
direction.
Even if you downshift the transmission from the ”D” position to ”4”
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.
Resuming the preset speed
If the preset speed is cancelled by pulling the control lever or by
depressing the brake pedal, pushing the lever up in the ”RES/ACC”
direction will restore the speed set prior to cancellation. However,
once the vehicle speed falls below about 40 km/h (25 mph), the
preset speed will not be resumed.

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171
Cruise control failure warning
If the ”CRUISE” indicator light in the instrument cluster flashes
when using the cruise control, push the main switch to turn the
system off and then push it again to turn it on.
If any of the following conditions then occurs, there is some trouble
in the cruise control system.
The indicator light does not come on.
The indicator light flashes again.
The indicator light goes out after it comes on.
If this is the case, contact your Lexus dealer and have your Lexus
inspected.
ELECTRONICALLY MODULATED
AIR SUSPENSION
(U.S.A. ONLY)
This electronically modulated air suspension adjusts the
damping effect on the shock absorbers and the vehicle height.
This adjustment is automatically made in response to the driving
conditions to provide good riding comfort and stability in all
driving conditions.
(a) Vehicle height adjustment
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This system maintains a stable vehicle height, regardless of
occupants and luggage weight. You can select one of the
following modes using a selector switch.

STARTING AND DRIVING
172”NORMAL” mode For driving on roads with a normal surface.
”HIGH” mode For driving on rough roads which are unsurfaced
or continually bumpy.
The damping effect is set slightly firmer in ”HIGH” mode. So you
may feel the vibration of the vehicle compared to in ”NORMAL”
mode. However, this does not mean a malfunction in the system. We
recommend you use a ”NORMAL” mode in normal driving.
To change the mode, push the selector switch.
”NORMAL” mode
The vehicle height remains at normal height at all driving speeds.
”HIGH” mode
The vehicle height switches between the following two vehicle
heights according to the driving conditions:
Vehicle height
Driving condition
NormalMedium and high speed driving
HighLow speed driving
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The indicator light shows ”HIGH” mode is selected.
When you turn the ignition key to the ”ON” position, the indicator
light will come on for 2 seconds in any mode.
NOTICE
For vehicles equipped with the height control switch, be sure to
turn the ignition switch off before jacking. If this is not done, the
vehicle height adjustment function will operate, which may
cause body damage.
(b) Malfunction warning
If the ”HI” indicator light blinks, there is a malfunction in this
system. Have the system checked by your Lexus dealer at the first
opportunity.

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173
TRACTION CONTROL SYSTEM
The traction control system automatically helps control the
spinning of the rear wheels which may occur when accelerating
on slippery road surfaces, thus assisting driver to control the
driving power of the rear wheels.
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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.
When the traction control system is operating, you may feel
vibration 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 174.
CAUTION
Under certain slippery road conditions, full traction of the
vehicle and power to the rear wheels cannot be maintained,
even though the traction control system is in operation. Do not
drive the vehicle under any speed or maneuvering conditions
which will cause the vehicle to lose traction. In situations
where the road surface is covered with ice or snow, your
vehicle should be fitted with snow tires or tire chains. Always
drive at an appropriate and cautious pace.

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174
VEHICLE SKID CONTROL SYSTEM
The vehicle skid control system helps to provide comprehensive
control of the systems such as an antilock 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.
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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 slight clicking noise 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 selfcheck
mode and does not indicate a malfunction.
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You can turn off the vehicle skid control system by pushing the
”VSC OFF” switch. The ”VSC OFF” indicator comes on. At
this time, the traction control system also turns off. You cannot
turn off either one of them. Pushing the ”VSC OFF” switch a
second time turns the system back on and extinguishes the ”VSC
OFF” indicator light.
When you turn the ignition switch on, this system always turns on.

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175
Vehicle skid control failure warning
31L073
In the following cases, the warning message appears and the
reminder light next to the warning message and the ”VSC OFF”
indicator light come on. And the warning tone also sounds.
(a) After the removal of the battery terminals (See ”Initial
adjustment of vehicle skid control system” described below.)
(b) If the vehicle skid control system malfunctions
If the message appears for the cause of (b), have your vehicle
checked by Lexus dealer as soon as possible.
Although the message appears, there is no problem to continue your
normal driving.
Initial adjustment of vehicle skid control system
After the battery terminals are disconnected, an initial adjustment
should be made. At this time, the reminder light comes on and the
warning message appears in the multi information display.
Make an initial adjustment in the following ways:
1. Apply the parking brake and put the transmission in ”P”.
2. Connect the battery terminals.
3. Turn the ignition switch on. At this time, the ”VSC OFF”
indicator light comes on and then about 6 seconds later, the reminder
light comes on and the ”CHECK VSC” warning message appears in
the multi information display.
4. The warning message and the ”VSC OFF” indicator light go out
about 15 seconds after the ignition switch is turned on. If the vehicle
is shaken after the ignition switch is turned to ”ON”, it may take
longer to go out the warning message.
If the warning message does not go out about 1 minute after you turn
the ignition switch on, turn it off and then on again.
If the vehicle is on the moving object like a ship or turntable, an
accurate adjustment cannot be made. Move the vehicle on the
ground (or the part not causing vibrations to the vehicle) and make
an adjustment from step 1.

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176
CAUTION
Do not rely excessively on the vehicle skid control system.
Even if the vehicle skid control system is operating, it is not
that your vehicle is absolutely safe. Reckless driving will
result in an unexpected accident. Always keep safety
driving in mind. If the slip indicator light flashes, sounding
an alarm, special care should be taken while driving.
Only use tires of specified size. The size, manufacturer,
brand and tread pattern for all 4 tires should be the same.
If you use the tires other than specified, or different type or
size, the vehicle skid control system may not function
correctly. When replacing the tires or wheels, contact your
Lexus dealer.
BRAKE SYSTEM
The tandem master cylinder brake system is a hydraulic system with
two separate subsystems. If either subsystem 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 powerassist 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!
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.

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177
Antilock brake system
The antilock brake system is designed to automatically help
prevent lockup 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 antilock 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 antilock brake system is in the selfcheck mode, and
does not indicate a malfunction.
Effective way to press the ABS brake pedal: When the antilock
brake system function is in action, you may feel the brake pedal
pulsating and hear a noise. In this situation, to let the antilock brake
system work for you, just hold the brake pedal down more firmly.
Do not pump the brake. This will result in reduced braking
performance.
The brake pedal pulsation caused by the antilock brake system may
indicate hazardous road surface conditions. Although the antilock
brake system assists in providing vehicle control, it is still important
to drive with all due care, because the antilock brake system cannot
overcome the laws of physics that act on your vehicle:
Braking capability is dependent on tire friction with the road
surface.Even though the antilock brake system is operating, a driver
cannot maintain full control on certain slippery road surfaces,
when cornering at high speeds, or in violent maneuvers.
Avoid high speeds on wet roads. The antilock brake system
cannot eliminate the risk of hydroplaning and loss of tire friction.
Always maintain a safe distance from the vehicle in front of you.
Compared with vehicles not fitted with an antilock brake system,
your vehicle may require a longer stopping distance in the following
cases:
Driving on rough, gravel or snowcovered roads.
Driving with tire chains installed.
Driving on roads where the road surface is pitted or has other
differences in surface height.