1999 Lexus LS400 lexus LS400 1999 Electrical Components / LEXUS 1999 LS400 OWNER'S MANUAL (OM50514U)

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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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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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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.

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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.

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ºABSº warning light
31L019-2

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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.

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1. Summer tires
Summer tires are high±speed capability tires best suited
to highway driving under dry conditions.
Since summer tires do not have the same traction
performance as snow tires, summer tires are
inadequate for driving on snow±covered or icy roads.
For driving on snow±covered or icy roads, we
recommend using snow tires. If installing snow tires, be
sure to replace all four tires.
2. All season tires
All season tires are designed to provide better traction
in snow and to be adequate for driving in most winter
conditions, as well as for use all year round.
All season tires, however, do not have adequate traction
performance compared with snow tires in heavy or loose
snow. A lso, all season tires fall short in acceleration and
handling performance compared with summer tires in
highway driving.