traction control Lexus GX470 2005 Engine / LEXUS 2005 GX470 (OM60B11U) User Guide

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433
VEHICLE STABILITY CONTROLSYSTEM
The vehicle stability control system helps provide
integrated control of the systems such as anti±lock brake
system, traction control, engine control, 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 operating steering wheel
abruptly.
This system activates when the vehicle speed about more than
15 km/h (9mph).
You may hear a 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 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 unexpected accident. If the
slip indicator light blinks and an alarm sounds,
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.

Slip indicator light
If the vehicle is going to skid during driving, the slip indicator
light blinks and an alarm sounds intermittently. Special care
should be taken while driving.

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435

The indicator light comes on when the system is on while
driving.
NOTICE
Make sure that the center differential lock indicator light
goes off before normal driving.
ªVSC TRACº warning light
This light warns that when there is a problem somewhere in the
following. 
Vehicle stability control system
 Active traction control system
 Downhill assist control system
 Hill±start assist control
When the system is normal and the ignition key is turned to
ªONº, the warning light will come on and will go off after a few
seconds. It is not a malfunction that the warning light may stay
on for 60 seconds after the ignition key is turned to the ªONº
position.
Depressing the brake pedal repeatedly may turn on the light.
It is normal if they go out after a few seconds.
If the light comes on while driving, the vehicle stability control
system does not work. However, as normal braking operates
when being applied, there is no problem to continue your
driving.
In the following cases, contact your Lexus dealer:
 The warning light does not come on after the ignition key is
turned to ªONº.
 The warning light remains on after the ignition key is turned
to ªONº.

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437
If the downhill assist control system indicator light flashes, the
transmission selector lever may be in ªNº or four±wheel drive
control lever may be in the ªHº position.
If the indicator light does not come on when the switch is
pushed, contact your Lexus dealer.

Slip indicator light
With the vehicle traveling at a speed of 25 km/h (15 mph) or
less, release your foot from the accelerator or brake pedal to
activate the system. The vehicle will descend the hill at a low
speed. While the system is operating, the slip indicator light on
the instrument panel will flash and the stop lights and high
mounted stoplight will be lit.
If you push the ªDACº switch to turn the system off while it is
in operation, the system will stop operating gradually. The
downhill assist control system indicator light will flash to alert
the driver. To continue driving at a low speed, push the ªDACº
switch to turn the system on.
The slip indicator light and downhill assist control system
indicator l
ight come on for a few seconds when the ignition key
is turned to ªONº. If any of the indicator lights does not come
on when the ignition is turned on, contact your Lexus dealer.
The brake actuator temperature increases during continuous
operation of the following systems.
 Active traction control system
 Vehicle stability control system
 Downhill assist control system
 Hill±start assist control
If the brake actuator temperature becomes too high while any
of the systems is operating, a buzzer will start to sound
intermittently to indicate that the downhill assist control system
can no longer operate. In this case, stop your vehicle
immediately at a safe place.
If the system continues to operate, the buzzer sound changes
from intermittent to continuous. (The continuous buzzer
sounds for about 3 seconds.) At this time, the slip indicator light
will come on and the downhill assist control system stops
operating temporarily in order to protect the brake actuator.
(Although the downhill assist control system does not operate,
it is no problem to continue your driving.) The system will be
automatically restored after a short time and the slip indicator
light goes out.

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438
ªVSC TRACº warning light
If there is any abnormality in the system, the ªVSC TRACº
warning light will come on. When the ªDACº switch is
pushed, the downhill assist control system indicator light
also flash.If the ªVSC TRACº warning light comes on, there may be an
abnormality in any of the following systems in addition to the
downhill assist control system.

Hill±start assist control
 Active traction control system
 Vehicle stability control system
When the system is normal and the ignition key is turned to
ªONº, the warning light will come on and will go off after a few
seconds. It is not a malfunction that the warning light may stay
on for 60 seconds after the ignition key is turned to the ªONº
position.
Depressing the brake pedal repeatedly may turn on the light.
It is normal if it goes out after a few seconds.
If the ªVSC TRACº warning light and slip indicator light comes
on while driving, the system does not work. However, as
normal braking operates when being applied, it is no problem
to continue your driving.
In the following cases, contact your Lexus dealer:
 The warning light does not come on after the ignition key is
turned to ªONº.
 The warning light remains on after the ignition key is turned
to ªONº.
 The warning light comes on while driving.

STARTING AND DRIVING
440Keep in mind the following when driving.

The hill±start assist control operates for 5 seconds
maximally. If both the brake and accelerator pedals remain
undepressed for longer than 5 seconds, the buzzer will
sound at more frequent intervals and the system will
gradually stop operating.
 The hill±start assist control is not designed as a function for
stopping the vehicle on a uphill slope. When stopping the
vehicle, be sure to depress the brake pedal.
The brake actuator temperature increases during continuous
operation of the following systems.
 Active traction control system
 Vehicle stability control system
 Downhill assist control system
 Hill±start assist control
If the brake actuator temperature becomes too high while any
of the systems is operating, a buzzer will start to sound
intermittently to indicate that the hill±start assist control can no
longer operate. In this case, stop your vehicle immediately at
a safe place. If the system continues to operate, the buzzer sound changes
from intermittent to continuous. (The continuous buzzer
sounds for about 3 seconds.) At this time, the slip indicator light
will come on and the hill±start assist control stops operating
temporarily in order to protect the brake actuator. (Although
the hill±start assist control does not operate, it is no problem
to continue your driving.) The system will be automatically
restored after a short time and the slip indicator light goes out.

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441
ªVSC TRACº warning light
If there is any abnormality in the system, the ªVSC TRACº
warning light will come on.
If the system malfunctions, the ªVSC TRACº warning light will
come on.
If the ªVSC TRACº warning light comes on, there may be an
abnormality in any of the following systems in addition to the
hill±start assist control.
Downhill assist control system
 Active traction control system
 Vehicle stability control system
When the system is normal and the ignition key is turned to
ªONº, the warning light will come on and will go off after a few
seconds. It is not a malfunction that the warning light may stay
on for 60 seconds after the ignition key is turned to the ªONº
position. Depressing the brake pedal repeatedly may turn on the light.
It is normal if it goes out after a few seconds.
If the ªVSC TRACº warning light and slip indicator light comes
on while driving, the system does not work. However, as
normal braking operates when being applied, it is no problem
to continue your driving.
In the following cases, contact your Lexus dealer:

The warning light does not come on after the ignition key is
turned to ªONº.
 The warning light remains on after the ignition key is turned
to ªONº.
 The warning light comes on while driving.

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444
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 anti±lock 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.ªABSº warning light

1U.S.A.2Canada
The light comes on when the ignition key is turned to the ªONº
position. If the anti±lock brake system and the brake assist
system work properly, the light turns off after a few seconds.
Thereafter, if either of the systems malfunctions, the light
comes on again.
When the ªABSº warning light is on (and the brake system
warning light is off), the anti±lock brake system, the brake
assist system, the active traction control system and the
vehicle stability control system do/does not operate, but the
brake system still operates conventionally.
When the ªABSº warning light is on (and the brake system
warning light is off), the anti±lock brake system does not
operate so that the wheels could lock up during a sudden
braking or braking on slippery road surfaces.

CHASSIS
582
Uniform tire quality grading
This information has been prepared in accordance
with regulations issued by the National Highway
Traffic Safety Administration of the U.S.
Department of Transportation. It provides the
purchasers and/or prospective purchasers of
Lexus vehicles with information on uniform tire
quality grading.
Your Lexus dealer will help answer any questions
you may have as you read this information.
DOT quality grades Ð All passenger car tires must
conform to Federal Safety Requirements in
addition to these grades. Quality grades can be
found where applicable on the tire sidewall
between tread shoulder and maximum section
width. For example: Treadwear 200 Traction AA
Temperature ATreadwear
Ð The treadwear grade is a comparative
rating based on the wear rate of the tire when tested
under controlled conditions on a specified government
test course. For example, a tire graded 150 would
wear one and a half (1 Ð 1/2) times as well on the
government course as a tire graded 100. The relative
performance of tires depends upon the actual
conditions of their use, however, and may depart
significantly from the norm due to variations in driving
habits, service practices and differences in road
characteristics and climate.
Traction AA, A, B, C Ð The traction grades, from
highest to lowest, are AA, A, B and C, and they
represent the tire's ability to stop on wet pavement
as measured under controlled conditions on specified
government test surfaces of asphalt and concrete.
A tire marked C may have poor traction performance.
Warning: The traction grade assigned to this tire is
based on braking (straight ahead) traction tests and
does not include cornering (turning) traction.

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587
TYPES OF TIRES
Determine what kind of tires your vehicle is originally
equipped with.
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. Also, all season tires fall short
in acceleration and handling performance compared
with summer tires in highway driving.
The details about how to distinguish summer tires
from all season tires are described on page 578.
CAUTION

Do not mix summer and all season tires on
your vehicle as this can cause dangerous
handling characteristics, resulting in loss of
control.
 Do not use tires other than the manufacturer's
designated tires, and never mix tires or
wheels of the sizes different from the
originals.

CHASSIS
591
INSTALLING SNOW TIRES ANDCHAINS
When to use snow tires or chains
Snow tires or chains are recommended when driving on
snow or ice.
On wet or dry roads, conventional or radial tires provide better
traction than snow or studded tires.
Snow tire selection
If you need snow tires, select tires of the same size,
construction and load capacity as the originally installed
tires. Also, all the tires must be the same brand and have
the same tread patterns.
Do not use tires other than stated above. Since your vehicle
has radial tires as original equipment, make sure your snow
tires also have radial construction. Do not install studded tires
without first checking local regulations for possible restrictions.
CAUTION
Observe the following instructions. Otherwise, an
accident may occur resulting in death or serious
injuries.
Do not use snow tires other than the manufacturer's
recommended size, as this may cause dangerous
handling characteristics resulting in loss of control.
 Do not use snow tires of different brands, sizes,
construction or tread patterns, as this may cause
dangerous handling characteristics resulting in loss
of control.
Snow tire installation
Snow tires should be installed on all wheels.
Installing snow tires on the rear wheels only can lead to an
excessive difference in road grip capability between the front
and rear tires which could cause loss of vehicle control.
CAUTION
Do not drive with the snow tires incorrectly inflated.
 Never drive over 105 km/h (65 mph) with any type of
snow tires.