tires Lexus GS430 2006 Scheduled Maintenance Guide / LEXUS 2006 GS430/GS300 FROM JAN. 2006 PROD. (OM30786U) User Guide

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427
VEHICLE STABILITY CONTROLSYSTEM
The vehicle stability control system helps provide
comprehensive control of the systems such as antilock
brake system, traction control, engine control, etc. This
system automatically controls the brakes and engine to
help prevent the vehicle from skidding when cornering on
a slippery road surface or operating steering wheel
abruptly.
The vehicle stability control system is activated when the
vehicle speed is about more than 15 km/h (9 mph).
You may hear a sound in the engine compartment for a few
seconds just after the vehicle begins to move. This means that
the system is in the self− check mode, but does not indicate a
malfunction.
CAUTION
 Do not rely excessively on the vehicle stability
control system. Even if the vehicle stability control
system is operating, you must always drive carefully
and attentively to avoid serious injury. Reckless
driving will result in an accident. If the slip indicator
light blinks, 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
stability control system may not function correctly.
When replacing the tires or wheels, contact your
Lexus dealer.
 In situations where the road surface is covered with
ice or snow, your vehicle should be fitted with snow
tires or tire chains.

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Variable gear ratio steering system failure
warning
G31044
If there is any malfunction in the system, the above message
appears and the master warning light comes on.
If the warning message and light come on while driving, the
system is not working. Although conventional steering
operates when maneuvered, a larger degree of wheel
maneuvering (than at the time when the system is functioning
properly) is needed when driving at low speed. At this time, the
center position of the steering wheel could be changed.
Although it is no problem to continue driving, have your vehicle
repaired at your Lexus dealer.
VEHICLE DYNAMICS
INTEGRATED MANAGEMENT (GS430 only)
Vehicle Dynamics Integrated Management (VDIM) helps
manage control for vehicle stability control system,
antilock brake system, brake assist system, traction
control system, engine output control, hillstart assist
control system and also manages variable gear ratio
steering system and electric power steering system.
In order to control sudden steering wheel operation and
the sideslip on slippery road surfaces, this system
provides excellent vehicle stability by automatically
controlling the brake, engine output and front wheel
angle.
The state of the tires will affect the performance of the vehicle
dynamics integrated management system. Be sure to check
the following:
 Are tires of specified size installed?
 Are tires of identical type installed?
 Do the tires have stipulated tire pressure?
 Are the tires worn?
A problem with the tires or modified suspension systems will
have an adverse effect on the system and may cause a
malfunction, so be careful.

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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.“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.

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Display
Indicator
statusMeaningsDo this
Tire pressure
warning lightONTire inflation
pressure is
lowAdjust the tireinflation
pressure
Multi
information
displayLOW TIRE
(PRESSURE)
Tire pressure
warning lightBlinkingTire pressure
warning
system
malfunctionHave the
system
checked at
your Lexus
dealer
Multi
information
displayCHECK
(TIRE
PRES-
SURE)
SYSTEM
CAUTION
If the tire pressure warning light comes on, be sure to
observe the following precautions. Failure to do so
could cause loss of vehicle control and result in death
or serious injury.
Vehicles with runflat tires:
 Decelerate to the lowest appropriate speed as soon
as possible. Do not drive over 90 km/h (55 mph).
 Check and adjust the tire inflation pressure
immediately.
 If the tire pressure warning light comes on even after
tire inflation pressure adjustment, it is probable that
you have a flat tire. Have the tire replaced by the
nearest Lexus dealer.
 Avoid abrupt maneuvering and braking. If the vehicle
tires deteriorate, you could lose control of the
steering wheel or the brakes.
Vehicles with standard tires:
 Stop your vehicle in a safe place as soon as possible.
Adjust the tire inflation pressure immediately.
 If the tire pressure warning light comes on even after
tire inflation pressure adjustment, it is probable that
you have a flat tire. Check the tires. If the tire is flat,
change to the spare tire and have the flat tire repaired
by the nearest Lexus dealer.
 Avoid abrupt maneuvering and braking. If the vehicle
tires deteriorate, you could lose control of the
steering wheel or the brakes.

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442The tire pressure warning light may turn on due to natural
causes such as natural air l
eaks or tire inflation pressure
changes caused by temperature. In this case, adjusting the
tire inflation pressure will turn off the light after a few minutes.
Pushing the tire pressure warning reset switch should not turn
off the tire pressure warning light. Adjusting the tire inflation
pressure will turn off the light.
The compact spare tire is not equipped with the tire pressure
warning valve and transmitter. If a tire goes flat, the warning
light will not turn off even though the flat tire is replaced with the
spare tire. Replace the spare tire with the repaired tire and
adjust the proper tire inflation pressure. The tire pressure
warning light will turn off after a few minutes.
CAUTION
Each tire, including the spare (if provided), should be
checked m onthly when cold and inflated to the inflation
pressure recommended by the vehicle manufacturer on
the vehicle placard or tire inflation pressure label (tire
and load information label). (If your vehicle has tires of
a different size than the size indicated on the vehicle
placard or tire inflation pressure label (tire and load
information label), you should determine the proper tire
inflation pressure for those tires.)
As an added safety feature, your vehicle has been
equipped with a tire pressure monitoring system
(TPMS–tire pressure warning system) that illuminates a
low tire pressure telltale (tire pressure warning light)
when one or more of your tires is significantly
underinflated. Accordingly, when the low tire pressure
telltale (tire pressure warning light) illuminates, you
should stop and check your tires as soon as possible,
and inflate them to the proper pressure. Driving on a
significantly underinflated tire causes the tire to
overheat and can lead to tire failure. Underinflation
also reduces fuel efficiency and tire tread life, and may
affect the vehicle’s handling and stopping ability.

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Please note that the TPMS (tire pressure warning
system) is not a substitute for proper tire maintenance,
and it is the driver’s responsibility to maintain correct
tire pressure, even if underinflation has not reached
the level to trigger illumination of the TPMS low tire
pressure telltale (tire pressure warning light).NOTICE
 Do not use liquid sealants for a flat tire as tire
pressure warning valve and transmitter will be
damaged.
 When the tires must be repaired or replaced, have
them repaired or replaced by your Lexus dealer or an
authorized tire dealer. The tire pressure warning
valves and transmitters will be affected by the
installation or removal of tires.

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444If the tire pressure warning light blinks...
G31048
If the tire pressure warning light blinks when the engine
switch “IGON” mode is selected, the tire pressure
warning system is not working properly.
The system will be disabled in the following conditions:
(When the condition becomes normal, the system will work
properly.)

If tires not equipped with tire pressure warning valves and
transmitters are used.
 If the ID code on the tire pressure warning valves and
transmitters is not registered.
 If electronic devices or facilities using similar radio wave
frequencies are nearby.
 If a radio set at similar frequencies is in use in the vehicle. 
If a window tint that affects the radio wave signals is
installed.
 If the tire pressure warning select switch is set to a dif ferent
tire setting.
 If there is a lot of snow or ice on the vehicle, in particular
around the wheels or wheel housings.
 If non− genuine Lexus wheels are used.
 If tire chains are used.
 If the tire inflation pressure is more than 500 kPa (5.1
kgf/cm
2 or bar, 73 psi).
If the tire pressure warning light blinks frequently when the
engine switch “IG −ON” mode is selected, have it checked by
your Lexus dealer.
Even if you use genuine wheels, the tire pressure warning
system may not work properly with some types of tires.
Pushing the tire pressure warning reset switch should not turn
off the tire pressure warning light.

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Replacing tires and wheels
When replacing the tires and wheels, be sure to install tire
pressure warning valves and transmitters. ID codes on the tire
pressure warning valves and transmitters are registered on the
tire pressure warning ECU. When replacing a tire pressure
warning valve and transmitter, it is necessar y to register the ID
code of tire pressure warning valve and transmitter. Have the
ID code registered by your Lexus dealer.
If the ID code is not registered, the system will not work
properly. After about 1 hour, the tire pressure warning light
blinks to indicate a system malfunction.
NOTICE
When the tires or tire pressure warning valves and
transmitters must be replaced, have them replaced by
your Lexus dealer. The tire pressure warning valves
and transmitters will be affected by the installation or
removal of tires.
Tire pressure warning reset switch
G31004a
When initializing the system, the present tire inflation pressure
is stored as standard. The tire pressure warning system
determines decreased air pressure by comparing the present
and the standard tire inflation pressures. When you change
the set tire inflation pressure, it is necessary to initialize the tire
pressure warning system.
 When rotating the tires on vehicles differing with front and
rear tire inflation pressures.
 When changing the tire inflation pressure by changing
traveling speed or load weight, etc.
 When changing the tire size.

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To initialize the system, perform the following:
1. Park
the vehicle in a safe place and select the engine switch
in “OFF” mode.
2. Adjust the pressure of all the installed tires to the specified
cold tire inflation pressure level. (See “Tire and wheels” on
pages 542 and 546.)
3. Select the engine switch in “IG −ON” mode.
4. Push and hold the tire pressure warning reset switch until
the tire pressure warning light blinks slowly three times and the
message “PRESSURE INITIAL” appears on the
multi−information display.
5. Wait for a few minutes with the engine switch in “IG −ON”
mode, and then select the engine switch in “OFF” position.
If you push the tire pressure reset switch while the vehicle is
moving, initialization is not performed.
If you push the tire pressure reset switch accidentally and
initialization is performed, adjust the tire inflation pressure to
the specified level and initialize the system again.
G31007
If the tire pressure warning light does not blink slowly three
times and the message “PRESSURE INITIAL” does not
appear on the multi −information display when you push and
hold the reset switch, initialization has failed and the tire
pressure warning system may not work properly. In this case,
initialize the system again. If initialization cannot be
performed, have the system checked at your Lexus dealer.

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CAUTION
Do not push the reset switch without first adjusting the
tire inflation pressure to the specified level. Otherwise,
the tire pressure warning light may not come on even if
the tire inflation pressure is low, or it may come on when
the tire inflation pressure is actually normal.
Tire pressure warning select switch
G31005a
 1 Main position 22nd position
2 sets of tire pressure warning valve and transmitter ID codes
can be registered.
Once a second set of tires is registered at “2nd”, you can switch
between tire set settings simply by pressing the tire pressure
warning select switch.
There are 2 settings
“MAIN” position: The ID code of the tire pressure warning valve
and transmitter on the tires originally installed on the vehicle is
registered.
“ 2nd ” position: The code is not registered. When you replace
a new set of tires, purchase tire pressure warning valves and
transmitters from your Lexus dealer and have the new ID code
registered by your Lexus dealer.