2003 TOYOTA SIENNA ECU

03 SIENNA_U (L/O 0207)
2352003 MY SIENNA (OM45410U)
BRAKE ASSIST SYSTEM
When you slam the brakes on, the
brake assist system judges as an emer-
gency stop and provides more powerful
braking for a driver who cannot hold
down the brake pedal firmly.
When you slam the brakes on, more pow-
erful 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 mal-
function.
The brake assist system becomes opera-
tive 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).
For an explanation of this system’s warn-
ing light, see “Service reminder indicators
and warning buzzers” in Section 15.
The brake pad wear limit indicators on
your disc brakes give a warning noise
when the brake pads are worn to where
replacement is required.
If you hear a squealing or scraping noise
while driving, have the brake pads
checked and replaced by your Toyota
dealer as soon as possible. Expensive ro-
tor damage can result if the pads are not
replaced when necessary.When stowing luggage or cargo in the
vehicle, observe the following:
Put luggage or cargo in the luggage
compartment when at all possible. Be
sure all items are secured in place.
Be careful to keep the vehicle bal-
anced. Locating the weight as far for-
ward as possible helps maintain bal-
ance.
For better fuel economy, do not carry
unneeded weight.
CAUTION
To prevent luggage or packages
from sliding forward during braking,
do not stack anything in the lug-
gage compartment higher than the
seatbacks. Keep luggage or pack-
ages low, as close to the floor as
possible.
Never allow anyone to ride in the
luggage compartment. It is not de-
signed for passengers. They should
ride in their seats with their seat
belts properly fastened. Otherwise,
they are much more likely to suffer
serious bodily injury, in the event
of sudden braking or a collision.
Brake pad wear limit
indicators
Luggage stowage pr
ecautions

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Do not drive with objects left on
top of the instrument panel. They
may interfere with the driver’s field
of view. Or they may move during
sharp vehicle acceleration or turn-
ing, and impair the driver’s control
of the vehicle. In an accident they
may injure the vehicle occupants.
NOTICE
Do not load the vehicle beyond the
vehicle capacity weight specified in
Section 8.
The roof luggage carrier consists of
roof rails (1) attached to the roof and
sliding cross rails (2).
To adjust the positions of cross rails, do
this.1. Turn the knobs counterclockwise to loosen the cross rails.
2. Slide the cross rails to the desired position for loading the luggages of
various sizes.
3. After adjusting, be sure to tighten the cross rails by turning knobs clockwise.
Follow the manufacture’s instructions and
precautions when installing the attach-
ments or their equivalent.
CAUTION
When you load cargo on the roof lug-
gage carrier, observe the following:
Place the cargo so that its weight
is distributed evenly between the
front and rear axles.
If loading long or wide cargo, never
exceed the vehicle overall length or
width. (See “Dimensions and
weight” in Section 8 for information
on your vehicle overall length and
width.)
Before driving, make sure the cargo
is securely fastened on the roof
luggage carrier.
Avoid sudden starts, sharp turns or
sudden braking.
If driving for a long distance, on
rough roads, or at high speeds,
stop the vehicle now and then dur-
ing the trip to make sure the cargo
remains in its place.
Do not exceed 50 kg (110 lb.) cargo
weight on the roof rails. However,
if the allowable cargo weight of the
cross rails is under 50 kg (110 lb.)
observe the load limit.
Roof luggage carrier

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Do not drive in excess of the speed
limit. Even if the legal speed limit
permits it, do not drive over 140
km/h (85 mph) unless your vehicle
has highspeed capability tires.
Driving over 140 km/h (85 mph) may
result in tire failure, loss of control
and possible injury. Be sure to con-
sult a tire dealer to determine
whether the tires on your vehicle
are highspeed capability tires or
not before driving at such speeds.
Do not continue normal driving
when the brakes are wet. If they are
wet, your vehicle will require a
longer stopping distance, and it
may pull to one side when the
brakes are applied. Also, the park-
ing brake will not hold the vehicle
securely.
Make sure you have a proper freeze
protection of engine coolant.
Your coolant must contain ethyleneglycol
type coolant for a proper corrosion
protection of aluminum components. Use
“Toyota Genuine Long Life Coolant” or
equivalent.
See Section 72 for details about coolant
type selection.
NOTICE
Do not use alcohol type antifreeze or
plain water alone.
When it is extremely cold, we recommend
to use 60% solution for your Toyota, to
provide protection down to about 50C
(58 F). Do not use more than 70% solu-
tion for better coolant performance.
Check the condition of the battery and
cables.
Cold temperatures reduce the capacity of
any battery, so it must be in top shape
to provide enough power for winter start-
ing. Section 73 tells you how to visually
inspect the battery. Your Toyota dealer
and most service stations will be pleased
to check the level of charge. Make sure the engine oil viscosity is
suitable for the cold weather.
See Section 72 for recommended viscos-
ity. Leaving a heavy summer oil in your
vehicle during winter months may cause
harder starting. If you are not sure about
which oil to use, call your Toyota deal-
er—he will be pleased to help.
Keep the door locks from freezing.
Squirt lock deicer or glycerine into the
locks to keep them from freezing.
Use a washer fluid containing an anti-
freeze solution.
This product is available at your Toyota
dealer and most auto parts stores. Follow
the manufacturer ’s directions for how
much to mix with water.
NOTICE
Do not use engine antifreeze or any
other substitute because it may dam-
age your vehicle’s paint.
Winter driving tips

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Total trailer weight Tongue loadTongue load
Total trailer weight 
100 = 9 to 11%
(∗
1)
or 15% (∗
2)
The trailer cargo load should be
distributed so that the tongue load
is 9 to 11% for weight carrying
hitch
(∗
1) or 15% for weight distrib-
ut i ng hi t ch ( ∗
2) of the total trailer
weight, not exceeding the maximum
load of the following.
Weight carrying hitch
Without towing package 90 kg (200 lb.)
With towing package
158 kg (350 lb.)
Weight distributing hitch With towing package
238 kg (525 lb.)
Never load the trailer with more
weight in the back than in the
front. About 60% of the trailer load
should be in the front half of the
trailer and the remaining 40% in the
rear.
HITCHES
If you wish to install a trailer hitch, you
should consult with your Toyota dealer.
Use only a hitch recommended by the
hitch manufacturer and the one which
conforms to the total trailer weight
requirement.
The hitch must be bolted securely to
the vehicle frame and installed accord-
ing to the hitch manufacturer ’s instruc-
tions.
The hitch ball and king pin should have
a light coat of grease.
Toyota recommends removing the trail-
er hitch whenever you are not towing
a trailer to reduce the possib ility of
additional damage caused by the hitch
if your vehicle is struck from behind.
After removing the hitch, seal any
mounting holes in the vehicle body to
prevent entry of pollutants such as ex-
haust fumes, dirt, water, etc.
NOTICE
Do not use axlemounted hitches as
they can cause damage to the axle
housing, wheel bearings, wheels or
tires. Also, never install a hitch which
may interfere with the normal function
of an Energy Absorbing Bumper, if so
equipped.
BRAKES AND SAFETY CHAINS
Toyota recommends trailers with
brakes that conform to any applica-
ble federal and state/provincial regu-
lations.

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A safety chain must always be used
between the towing vehicle and the
trailer. Leave sufficient slack in the
chain for turns. The chain should
cross under the trailer tongue to
prevent the tongue from dropping to
the ground in case it becomes dam-
aged or separated. For correct safety
chain procedures, follow the hitch or
trailer manufacturer ’s recommenda-
tions.
CAUTION
If the total trailer weight exceeds
453 kg (1000 lb.), trailer brakes are
required.
Never tap into your vehicle’s hy-
draulic system as it would lower its
braking effectiveness.
Never tow a trailer without using a
safety chain securely attached to
both the trailer and the vehicle. If
damage occurs to the coupling unit
or hitch ball, there is danger of the
trailer wandering over into another
lane.
TIRES
Ensure that your vehicle’s tires are
properly inflated. Adjust the tire pres-
sure to the recommended cold tire
pressure indicated below. (See Section
72 and Section 8 for instructions.):
Tire pressure, kPa (kgf/cm
2 or bar, psi)
240 (2.4, 35)
The trailer tires should be inflated to
the pressure recommended by the trail-
er manufacturer in respect to the total
trailer weight.
TRAILER LIGHTS
Trailer lights must comply with federal,
state/provincial and local regulations.
See your local recreational vehicle
dealer or rental agency for the correct
type of wiring and relays for your trail-
er. Check for correct operation of the
turn signals and stop lights each time
you hitch up. Direct splicing may dam-
age your vehicle’s electrical system
and cause a malfunction of your lights. BREAKIN SCHEDULE
Toyota recommends that you do not
tow a trailer with a new vehicle or a
vehicle with any new power train com-
ponent (engine, transmission, differen-
tial, wheel bearing, etc.) for the first
800 km (500 miles) of driving.
MAINTENANCE
If you tow a trailer, your vehicle will
require more frequent maintenance due
to the additional load. For this
information, please refer to the
scheduled maintenance information in
the “Scheduled Maintenance Guide” or
“Owner ’s Manual Supplement”.
Retighten all fixing bolts of the towing
ball and bracket after approximately
1000 km (600 miles) of trailer driving.
PRETOWING SAFETY CHECK
Check that your vehicle remains level
when a loaded or unloaded trailer is
hitched. Do not drive if the vehicle has
an abnormal noseup or nosedown
condition, and check for improper
tongue load, overload, worn suspension
or other possible causes.
Make sure the trailer cargo is securely
loaded so that it cannot shift.

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1. Get the required tools and sparetire.
1. Jack
2. Jack handle
3. Wheel nut wrench
4. Spare tire
To prepare yourself for an emergency, you
should fam iliarize yourself with the use of
the jack, each of the tools and their stor-
age locations.
Turn the jack joint by hand.
To remove: Turn the joint in direction 1
until the jack is free.
To store: Turn the joint in direction 2 until
the jack is firmly secured to prevent it
flying forward during a collision or s udden
braking.To remove the spare tire;
Open the back door and you will find the
spare tire clamp bolt near the back door
latch.
1. Loosen the spare tire clamp bolt by turning it counterclockwise with the
wheel nut wrench.
2. After the tire is lowered completely to the ground, remove the holding brack-
et.
Compact spare tire—
When storing the spare tire, put it in place
with the inner side of the wheel facing up.
Except compact spare tire—
When storing the spare tire, put it in place
with the outer side of the wheel facing up.

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Then secure the tire by repeating the
above removal steps in reverse order to
prevent it from flying forward during a
collision or sudden braking.
Make sure to pull the tire straight up with-
out catching on any other part.
Do not overtighten the bolt. Stop turning
it when you begin to feel resistance on
your hand.
After storing the tire, make sure it is se-
curely locked by pushing it forward and
rearward.
NOTICE
To secure spare tire clamp bolt:
Do not use impact wrench, but
wheel nut wrench.
 Tighten the spare tire clamp bolt to
hold the spare wheel carrier by the
hook securely.
2. Block the wheel diagonally opposite
the flat tire to keep the vehicle from
rolling when it is j acked up.
When blocking the wheel, place a wheel
block from the front for the front wheels
or from the rear for the rear wheels.Steel wheels
Aluminium wheels
—Blocking the wheel —Removing wheel ornament

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CAUTION
Never use oil or grease on the bolts
or nuts. Doing so may lead to over-
tightening the nuts and damaging the
bolts. The nuts may loose and the
wheels may fall off, which could cau-
se a serious accident. If there is oil
or grease on any bolt or nut, clean
it.
9. Lower the vehicle completely andtighten the wheel nuts.
Turn the jack handle counterclockwise to
lower the vehicle.
Use only the wheel nut wrench to tighten
the nuts. Do not use other tools or any
additional leverage other than your hands,
such as a hammer, pipe or your foot.
Make sure the wrench is securely en-
gaged over the nut.
Tighten each nut a little at a time in the
order shown. Repeat the process until all
the nuts are tight.
CAUTION
When lowering the vehicle, make
sure all portions of your body and
all other persons around will not be
injured as the vehicle is lowered to
the ground.
Have the wheel nuts tightened by
torque wrench at 104 N·m (10.5
kgf·m, 77 ft·lbf), as soon as pos-
sible after changing wheels. Other-
wise, the nuts may loosen and the
wheels may fall off, which could
cause a serious accident.
—Lowering your vehicle