brake lexus LS400 1999 Electrical Components / LEXUS 1999 LS400 (OM50514U) Owner's Guide

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.

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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

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311
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
ºPº.
2. Connect the battery terminals.
3. Turn the ignition switch on. At this time, the ºVSC
OFFº indicator light comes on and then about 6 seconds
later, the reminder light comes on and the ºCHECK VSCº
warning message appears in the multi information
display.
4. The warning message and the ºVSC OFFº indicator
light go out about 15 seconds after the ignition switch is
turned on. If the vehicle is shaken after the ignition
switch is t urned to ºONº, 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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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!

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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.

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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.

STARTING AND DRIVING
316The brake pedal pulsation caused by the anti±lock brake
system may indicate hazardous road surface
conditions. Although the anti±lock brake system assists
in providing vehicle control, it is still important to drive
with all due care, because the anti±lock 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 anti±lock 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 anti±lock 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
anti±lock brake system, your vehicle may require a
longer stopping distance in the following cases:
 Driving on rough, gravel or snow±covered roads.
 Driving with tire chains installed.
 Driving on roads where the road surface is pitted or
has other differences in surface height.

STARTING AND DRIVING
318This light comes on when the ignition key is turned
to the ºONº position. After about a few seconds, the
light will go off.
If either of the following conditions occurs, this indicates
a malfunction somewhere in the parts monitored by the
warning light system. Contact your Lexus dealer as
soon as possible to service the vehicle.

The light does not come on as described above, or
remains on.
 The light comes on while driving.
Even if the anti±lock brake system should fail, the brake
system will still operate conventionally. But when the
ºABSº warning light is on (and the brake system warning
light is off), anti±lock brake system is not assisting brake
performance so that the wheels could lock up during a
sudden brake or braking on slippery road surfaces.
Have your vehicle checked by your Lexus dealer as
soon as possible.
Drum±in±disc type parking brake system
Your vehicle has a drum±in±disc type parking brake
system. This type of brake system needs
bedding±down of the brake shoes periodically or
whenever the parking brake shoes and/or drums are
replaced.
Have your Lexus dealer perform the bedding±down.

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Brake pad wear limit warning message
31L082
When your brake pads are worn enough to require
replacement, the brake pad wear warning message
in the multi information display appears.
If the warning message in the multi information display
appears while driving, have the brake pads checked and
replaced by your nearest Lexus dealer immediately.
Continuous driving without replacing the brake pads will
cause expensive rotor damage and increasing brake
pedal effort to get the same stopping distance.TYPES OF TIRES
Determine what kind of tires your vehicle is originally
equipped with.