2006 Lexus GS430 Scheduled Maintenance Guide / LEXUS 2006 GS430/GS300 FROM JAN. 2005 PROD. OWNER'S MANUAL (OM30649U)

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Antilock brake system
The antilock brake system is designed to automatically
help prevent lockup of the wheels during a sudden
braking or braking on slippery road surfaces. This assists
in providing directional stability and steering
performance of the vehicle under these circumstances.
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. This will result in reduced braking performance.
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).
Depressing the brake pedal on slippery road surfaces such as
on a manhole cover, a steel plate at a construction site, joints
in a bridge, etc. on a rainy day tends to activate the anti −lock
brake system.
You may hear a click or motor sound in the engine
compartment for a few seconds when the engine is started or
just after the vehicle begins to move. This means that the
anti−lock brake system is in the self− check mode, and does not
indicate a malfunction. When the antilock brake system is activated, the
following conditions may occur. They do not indicate a
malfunction of the system:

You may hear the anti− lock brake system operating and feel
the brake pedal pulsating and the vibrations of the vehicle
body and steering wheel. You may also hear the motor
sound in the engine compartment even after the vehicle is
stopped.
 At the end of the anti−lock brake system activation, the
brake pedal may move a little forward.

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CAUTION
Do not overestimate the antilock brake system:
Although the antilock brake system assists in
providing vehicle control, it is still important to drive
with all due care and maintain a moderate speed and
safe distance from the vehicle in front of you, because
there are limits to the vehicle stability and effectiveness
of steering wheel operation even with the antilock
brake system on.
If tire grip performance exceeds its capability, or if
hydroplaning occurs during high speed driving in the
rain, the antilock brake system does not provide
vehicle control.
Antilock brake system is not designed to shorten the
stopping distance: Always drive at a moderate speed
and maintain a safe distance from the vehicle in front of
you. Compared with vehicles without 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 over the steps such as the joints on the road.
 Driving on roads where the road surface is pitted or
has other differences in surface height.
Install all 4 tires of specified size at appropriate
pressure: The antilock brake system detects vehicle
speeds using the speed sensors for respective wheels’
turning speeds. The use of tires other than specified
may fail to detect the accurate turning speed resulting
in a longer stopping distance.

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430“ABS” warning light
G31080
 1
U.S.A. 2Canada
GS430—The light comes on when the engine switch is
selected in “IG −ON” mode. If the anti −lock brake system and
the brake assist system work properly, the light turns off in a
few seconds after the engine is started.
GS300—The light comes on for a few seconds when the
engine switch is selected in “IG −ON” mode. It indicates the
anti− lock brake system and the brake assist system work
properly.
If either system malfunctions, the light comes on again.
When the “ABS” warning light is on, the anti− lock brake system
and the brake assist system do not operate, but the brake
system still operates conventionally. If either of the following conditions occur, this indicates a
malfunction
somewhere in the components monitored by
the warning light system. Contact your Lexus dealer as
soon as possible to service the vehicle.
 The light does not come on when engine switch is selected
in “IG− ON” mode.
 The light remains on after the engine is started (GS430), or
remains on after the engine switch is selected in “IG −ON”
mode (GS300).
 The light comes on while you are driving.
A warning light turning on briefly during operation does not
indicate a problem.
CAUTION
If the “ABS” warning light remains on together with the
brake system warning light (red), immediately stop your
vehicle at a safe place and contact your Lexus dealer.
In this case, not only the antilock brake system will fail
but also the vehicle will become extremely unstable
during braking.
GS430 only—Either of the following conditions may
occur, but does not indicate a malfunction:
 The light may stay on for about 60 seconds after the engine
is started. It is normal if it turns off after a while.
 Depressing the brake pedal repeatedly may turn on the
light. It is normal if it turns off after a few seconds.

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Drumindisc 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.
Brake assist system
When you slam the brakes on, the brake assist system
judges as an emergency stop and provides more powerful
braking for a driver who cannot hold down the brake pedal
firmly.
When you slam the brakes on, more powerful braking will be
applied. At this time, you may hear a sound in the engine
compartment and feel the vibrations of the brake pedal. This
does not indicate a malfunction.
The brake assist 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).
The brake assist system may not work for about 60 seconds
after the engine is started.
For an explanation of this system’s warning light, see “ABS”
warning light on page 78 or 430.
BRAKE PAD WEAR LIMIT
INDICATORS
G31006
The brake pad wear limit indicators on your disc brakes
give a warning noise when the brake pads are worn to the
extent that replacement is required.
If you hear a squealing or scraping noise while driving, have
the brake pads checked and replaced by your Lexus dealer as
soon as possible. Expensive rotor damage can result if the
pads are not replaced when needed.
GS430 front brake only—
The high brake performance is achieved by proper wear of
brake pads and discs. As a result, the brake discs may wear
earlier than the ones on the conventional brake system.
When brake pads are replaced, brake disc thickness is
required to be measured.
It is dangerous to continue driving when brake pads and discs
have exceeded the wear limit.

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ELECTRIC POWER STEERINGSYSTEM
The electric power steering system, using an electric
motor, assists the turning of the steering wheel.
In the following cases, you may feel the steering becomes
heavy. However, the electric power steering system
warning light does not come on. (Because it is not a
malfunction.)
When maneuvering or turning frequently over a long time, the
power steering effect will be reduced to prevent the system
from overheating. A void turning the steering wheel, or stop the
vehicle and select the engine switch in “ACC” or “OFF” mode.
The system will become cool in about 10 minutes.
NOTICE
Frequent maneuvering and turning over a long time may
cause damage to the system in which the mechanism
prevents overheating of the electric power steering
system.
When the battery is discharged, check the battery’s condition.
If necessary, recharge or replace the battery. For details, see
“Checking battery condition” on page 571.
G31040
 Electric power steering system warning light
The light comes on when the engine switch is selected in
“IG−ON” mode. If the electric power steering system works
properly, the light turns off after a few seconds. If the system
has malfunctions, the light comes on again.
If the following conditions occur, this indicates a
malfunction somewhere in the components monitored by
the warning light system. Contact your Lexus dealer as
soon as possible to service the vehicle.
 The light does not come on when the engine switch is
selected in “IG −ON” mode or remains on.
 The light stays on while you are driving.

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CAUTION
If the electric power steering system warning light
comes on, take your vehicle to your Lexus dealer as
soon as possible. In this case, more effort is required
for the steering wheel to turn than usual. Drive your
vehicle while firmly gripping the steering wheel.
TIRE PRESSURE WARNINGSYSTEM
G31003
Low tire pressure warning light
The light warns you that the tire inflation pressure is low.
The low tire pressure warning light comes on when the engine
switch is selected in “IG−ON” mode and goes off after a few
seconds. This means the low tire pressure warning light is
operating properly. If the tire inflation pressure becomes low,
the light comes on again. At this time, the master warning light
comes on and the message “LOW TIRE” appears on the
multi−information display.

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434If the low tire pressure warning light does not go off or comes
on during driving, it indicates that tire inflation pressure is low.
Make
sure there is no flat tire. If the light comes on again even
after tire inflation pressure adjustment, you may have a flat tire.
If there is not adequate air pressure in the tires, the light will not
go off.
The light may turn on due to natural causes such as natural air
leaks or tire inflation pressure changes caused by
temperature. In this case, adjusting the tire inflation pressure
will turn off the light.
The tire pressure warning syst em is not a substitute for
checking tire inflation pressure.
For details about adjusting the tire inflation pressure, see
“Checking tire inflation pressure” on page 539.
If the low tire pressure warning light comes on, the action you
must take is different depending on the type of tires used. Vehicles with runflat tires:
Stop your vehicle at a safe place as soon as possible and
check that the tire inflation pressure
is as specified on the tire
and loading information label. If the low tire pressure warning
light comes on even after tire inflation pressure adjustment, it
is probable that you have a flat tire. If you cannot verify the tire
inflation pressure soon, go to the nearest Lexus dealer or
authorized tire dealer at the moderate speed and do not ever
exceed 90 km/h (55 mph) and have all your vehicle’s tires
checked and adjusted. And whether there is a flat tire or not
should be also checked at this time. If any tire must be
replaced, see “If you have a flat tire” on page 468.
If your vehicle is equipped with spare tire, the spare is not
equipped with the tire pressure sensor. So, the low tire
pressure warning light remains on even if the spare tire is
mounted.
The light goes off a few minutes after air is put into the deflated
tire.

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CAUTION
If the low tire pressure warning light comes on, take
your vehicle to the nearest Lexus dealer or authorized
tire dealer or gas station as soon as possible, observing
the following instructions:
 Decelerate as soon as possible to the most
appropriate speed that conditions permit. Do not
drive over 90 km/h (55 mph).
 Avoid abrupt steering wheel maneuvering and
braking. If the vehicle tires deteriorate, you could
lose control of the steering wheel or the brakes,
causing death or serious injury.
 The warning system may not activate immediately if
bursts or sudden air leakage should occur.
When the tyre pressure warning system warning light is
lit, one or more of your tyres is significantly
underinflated. You should stop and check your tyres
as soon as possible, and inflate them to the proper
pressure as indicated on the vehicle’s tyre information
placard. Driving on a significantly underinflated tire
causes the tyre to overheat and can lead to tyre failure.
Underinflation also reduces fuel efficiency and tyre
tread life, and may affect the vehicle’s handling and
stopping ability. Each tyre, including the spare, should
be checked monthly when cold and set to the
recommended inflation pressure as specified in the
vehicle placard and owner’s manual.
NOTICE
 Do not use liquid sealants for a flat tire as tire
pressure sensors will be damaged.
 Take due care not to go over a curb stone and be
careful of the holes in the road because deflated tire
pressure affects tire cushion performance. The
wheels, tires, body, suspension and other
components could be damaged.
 Your ground clearance is reduced if the runflat tire
goes flat so avoid driving over obstacles and drive
slowly on rough, unpaved roads and speed bumps.
Also, do not attempt to go through an automatic car
wash as the vehicle may get caught, resulting in
damage.
 When the tires must be replaced, have them replaced
by the nearest Lexus dealer or authorized tire dealer.
The tire pressure sensor will be affected by the
installation or removal of tires.
 When the tires must be replaced, replace the
grommets for tire pressure sensors as well.