2008 TOYOTA SIENNA traction control

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In the following cases, contact your Toyota
dealer:
The warning light does not come on
after the engine switch is turned to
“ON”.
The warning light remains on after the
engine switch is turned to “ON”.
The warning light comes on while driv-
ing.
The “TRAC OFF” indicator light will come
on when the “VSC” warning light comes
on even if the “TRAC OFF” switch is not
pushed. The traction control system automatical-
ly helps prevent the spinning of 4
wheels when the vehicle is started or
accelerated on slippery road surfaces.
When the engine switch is turned to “ON”,
the system automatically turns on.CAUTION
Under certain slippery road condi-
tions, full traction of the vehicle and
power against 4 wheels cannot be
maintained, even though the traction
control system is in operation. Do not
drive the vehicle under any speed or
maneuvering conditions which may
cause the vehicle to lose traction
control. In situations where the road
surface is covered with ice or snow,
your vehicle should be fitted with
snow tires or tire chains. Always
drive at an appropriate and cautious
speed for the present road condi-
tions.
NORMAL DRIVING MODE
Leave the system on during the ordi-
nary driving so that it can operate
when needed.
You may hear a sound in the engine
compartment for a few seconds just after
the vehicle begins to move. This means
that the traction control system is in the
self
−check mode, but does not indicate a
malfunction.
Traction control system
(allwheel drive models)

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When the traction control system is oper-
ating, the following conditions occur:
The system controls the spinning of the
4 wheels. At this time, the slip indica-
tor light blinks.
You may feel vibration or noise in your
vehicle, caused by operation of the
brakes. This indicates the system is
functioning properly.
The slip indicator light comes on for a few
seconds when the engine switch is turned
to “ON”. If the indicator light does not
come on when the engine switch is turned
on, contact your Toyota dealer.
“VSC” warning light
This light warns that there is a problem
somewhere in the traction control system
or the vehicle stability control system.
The light will come on when the engine
switch is turned to “ON” and will go off
after a few seconds.
If the light comes on while driving, the
system does not work. However, as con-
ventional braking operates when applied,
there is no problem to continue your driv-
ing. In the following cases, contact your Toyota
dealer:
The warning light does not come on
after the engine switch is turned to
“ON”.
The warning light remains on after the
engine switch is turned to “ON”.
The warning light comes on while driv-
ing.

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The vehicle stability control system
helps provide integrated control of the
systems such as an antilock brake
system, brake assist system, traction
control, engine control, etc. This sys-
tem automatically controls the brakes
and engine to help prevent the vehicle
from skidding when cornering on a slip-
pery road surface or operating steering
wheel abruptly.
The vehicle stability control system is acti-
vated 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 ve-
hicle stability control system. Even
if the vehicle stability control sys-
tem is operating, you must always
drive carefully and attentively to
avoid serious injury. Reckless driv-
ing will result in an unexpected ac-
cident. If the slip indicator light
flashes, 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 Toyota dealer. (See
“Checking and replacing tires” on
page 526 in Section 72.)
In situations where the road surface
is covered with ice or snow, your
vehicle should be fitted with snow
tires or tire chains.
If the vehicle is going to skid during driv-
ing, the slip indicator light blinks and an
alarm sounds intermittently. Special care
should be taken while driving.
The slip indicator light comes on for a few
seconds when the engine switch is turned
to “ON”. If the indicator light does not
come on when the engine switch is turned
on, contact your Toyota dealer.
Vehicle stability control
system

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“VSC” warning light
This light warns that there is a problem
somewhere in the vehicle stability control
system or the traction control system.
The light will come on when the engine
switch is turned to “ON” and will go off
after a few seconds.
If the light comes on while driving, the
system does not work. However, as con-
ventional braking operates when applied,
there is no problem to continue your driv-
ing.In the following cases, contact your Toyota
dealer:
The warning light does not come on
after the engine switch is turned to
“ON”.
The warning light remains on after the
engine switch is turned to “ON”.
The warning light comes on while driv-
ing.
Tw o −wheel drive models only—The “TRAC
OFF” indicator light will come on when the
“VSC” warning light comes on even if the
“TRAC OFF” switch is not pushed. The tire pressure warning system warns
you that the tire inflation pressure is
low.
The tire pressure warning system is not
a substitute for checking normal tire infla-
tion pressure. Check the tire inflation
pressure with a tire pressure gauge regu-
larly.
CAUTION
The warning system may not activate
immediately if a blowout or sudden
air leakage should occur.
Tire pressure warning system

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“ABS” warning light
Vehicles without the vehicle stability
control system—
The light comes on when the engine
switch is turned to the “ON” position. If
the anti−lock brake system works properly,
the light turns off after a few seconds.
Thereafter, if either of the systems mal-
functions, the light comes on again.
When the “ABS” warning light is on (and
the brake system warning light is off), the
anti −lock brake system does not operate,
but the brake system still operates con-
ventionally.
When the “ABS” warning light is on (and
the brake system warning light is off), the
anti −lock brake system does not operate
but the brake assist system still operates.
In this case the wheels could lock up
during a sudden braking or braking on
slippery road surfaces. If either of the following conditions
occurs, this indicates a malfunction
somewhere in the components moni-
tored by the warning light system. Con-
tact your Toyota dealer as soon as
possible to service the vehicle.
The light does not come on when the
engine switch is turned to the “ON”
position, or remains on.
The light comes on while you are driv-
ing.
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 warn-
ing light, immediately stop your ve-
hicle at a safe place and contact your
Toyota dealer.
In this case, not only the antilock
brake system will fail but also the
vehicle will become extremely unsta-
ble during braking.
Vehicles with the vehicle stability con-
trol system—
The light comes on when the engine
switch is turned to the “ON” 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 “ABS” warning light is on (and
the brake system warning light is off), the
anti −lock brake system, the brake assist
system, the traction control system and
the vehicle stability control system do not
operate, but the brake system still oper-
ates conventionally.
When the “ABS” 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.
If either of the following conditions
occurs, this indicates a malfunction
somewhere in the components moni-
tored by the warning light system. Con-
tact your Toyota dealer as soon as
possible to service the vehicle.

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This information has been prepared
in accordance with regulations issued
by the National Highway Traffic Safe-
ty Administration of the U.S. Depart-
ment of Transportation. It provides
the purchasers and/or prospective
purchasers of Toyota vehicles with in-
formation on uniform tire quality grad-
ing.
Your Toyota dealer will help answer
any questions you may have as you
read this information.
DOT quality grades—All passenger
vehicle tires must conform to Fed-
eral Safety Requirements in addi-
tion to these grades. Quality
grades can be found where appli-
cable on the tire sidewall between
tread shoulder and maximum sec-
tion width. For example: Treadwear
200 Traction AA Temperature ATreadwear—
The treadwear grade is
a comparative rating based on the
wear rate of the tire when tested un-
der controlled conditions on a speci-
fied government test course. For ex-
ample, a tire graded 150 would wear
one and a half (1 −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 hab-
its, service practices and differences
in road characteristics and climate. Traction AA, A, B, C—
The traction
grades, from highest to lowest, are
AA, A, B, and C, and they represent
the tire’s ability to stop on wet pave-
ment as measured under controlled
conditions on specified government
test surfaces of asphalt and concrete.
A tire marked C may have poor trac-
tion performance.
Warning: The traction grade assigned
to this tire is based on braking
(straight ahead) traction tests and
does not include cornering (turning)
traction.
—Uniform tire quality grading

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Determine what kind of tires your
vehicle is originally equipped with.1. Summer tires
Summer tires are high −speed capabil-
ity 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 pro-
vide 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 433.
CAUTION

Do not mix summer and all sea-
son tires on your vehicle as
this can cause dangerous han-
dling 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 originally equipped
tires and wheels.
Types of tires

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CAUTION
Sudden braking, acceleration and
steering when driving on a slippery
road surface may cause tire slip-
page and reduce your ability to
control the vehicle, resulting in an
accident.
Sudden changes in engine speed,
such as sudden engine braking,
may cause the vehicle to skid, re-
sulting in an accident.
After driving through a puddle,
lightly depress the brake pedal to
make sure that the brakes are func-
tioning properly. Wet brake pads
may prevent the brakes from func-
tioning properly. If the brakes on
only one side are wet and not func-
tioning properly, steering control
may be affected, resulting in an ac-
cident.
When encountering flooded roads
Do not drive on a road that has flooded
after heavy rain etc. Doing so may cause
serious damage to the vehicle.
NOTICE
Driving on a flooded road may cause
the engine to stall as well as cause
serious vehicle malfunctions such as
shorts in electrical components and
engine damage from water immersion.
In the event that you drive on a
flooded road and the vehicle is
flooded, be sure to have your Toyota
dealer check brake function, changes
in quantity and quality of oil and fluid
used for the engine, transaxle, trans-
fer (AWD vehicles), differential, etc.
and lubricant condition for the propel-
ler shaft (AWD vehicles), bearings and
suspension joints (where possible)
and the function of all joints and bea-
rings.
If you need greater traction while driv-
ing on sand, mud or snow covered
roadways, use tire chains on the front
wheels.
Always check your brakes for effective-
ness immediately after driving across
sand, mud, or water.
If operating in adverse conditions
frequently, vehicle maintenance should
be increased. (See the separate
“Scheduled Maintenance Guide” or
“Owner ’s Manual Supplement”.)
CAUTION
Observe the following tire instruc-
tions. Otherwise, an accident may oc-
cur resulting in death or serious inju-
ries.
Keep your tire inflation pressure at
the proper level. (See “Checking
tire inflation pressure” on page 523
in Section 72.)
Do not use tires (including snow
tires) of different brands, sizes,
construction or tread patterns. (See
“Checking and replacing tires” on
page 526 and “Installing snow tires
and chains” on page 530 in Section
72.)
Allwheel driving tips
(AWD models)