engine TOYOTA SIENNA 2003 XL20 / 2.G Workshop Manual

03 SIENNA_U (L/O 0207)
2512003 MY SIENNA (OM45410U)
Improving fuel economy is easy—just take
it easy. It will help make your vehicle last
longer, too. Here are some specific tips
on how to save money on both fuel and
repairs:
Keep your tires inflated at the cor-
rect pressure. Underinflation causes
tire wear and wastes fuel. See Section
72 for instructions.
Do not carry unneeded weight in
your vehicle. Excess weight puts a
heavier load on the engine, causing
greater fuel consumption.
Avoid lengthy warmup idling. Once
the engine is running smoothly, begin
driving—but gently. Remember, howev-
er, that on cold winter days this may
take a little longer.
Keep the automatic transmission
overdrive turned on when engine
braking is not required. Driving with
the overdrive off will reduce the fuel
economy. (For details, see “Automatic
transmission” in Section 16.)
Accelerate slowly and smoothly.
Avoid jackrabbit starts. Get into high
gear as quickly as possible.
Avoid long engine idling. If you have
a long wait and you are not in traffic,
it is better to turn off the engine and
start again later.
Avoid engine lugging or overrev-
ving. Use a gear position suitable for
the road on which you are travelling.
Avoid continuous speeding up and
slowing down. Stopandgo driving
wastes fuel.
Avoid unnecessary stopping and
braking. Maintain a steady pace. Try
to time the traffic signals so you only
need to stop as little as possible or
take advantage of through streets to
avoid traffic lights. Keep a proper dis-
tance from other vehicles to avoid sud-
den braking. This will also reduce wear
on your brakes.
Avoid heavy traffic or traffic jams
whenever possible.
Do not rest your foot on the brake
pedal. This causes premature wear,
overheating and poor fuel economy.
Maintain a moderate speed on high-
ways. The faster you drive, the greater
the fuel consumption. By reducing your
speed, you will cut down on fuel con-
sumption.
Keep the front wheels in proper
alignment. Avoid hitting the curb and
slow down on rough roads. Improper
alignment not only causes faster tire
wear but also puts an extra load on
the engine, which, in turn, wastes fuel.
Keep the bottom of your vehicle free
from mud, etc. This not only lessens
weight but also helps prevent corro-
sion.
Keep your vehicle tunedup and in
top shape. A dirty air cleaner, improp-
er valve clearance, dirty plugs, dirty oil
and grease, brakes not adjusted, etc.
all lower engine performance and con-
tribute to poor fuel economy. For longer
life of all parts and lower operating
costs, keep all maintenance work on
schedule, and if you often drive under
severe conditions, see that your vehicle
receives more frequent maintenance.
(For scheduled maintenance informa-
tion, please refer to the “Scheduled
Maintenance Guide” or “Owner ’s Manu-
al Supplement”.)
How to save fuel and make
your vehicle last longer

03 SIENNA_U (L/O 0207)
2522003 MY SIENNA (OM45410U)
CAUTION
Never turn off the engine to coast
down hills. Your power steering and
brake booster will not function with-
out the engine running. Also, the
emission control system operates
properly only when the engine is run-
ning.

03 SIENNA_U (L/O 0207)
2532003 MY SIENNA (OM45410U)
IN CASE OF AN EMERGENCY
If your vehicle will not start254
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If your engine stalls while driving 257
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If your vehicle overheats 257
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . \
If you have a flat tire 258
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . \
. . . . .
If your vehicle becomes stuck 268
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If your vehicle needs to be towed 269
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If you lose your keys 271
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . \
. . . .
If you lose your wireless remote control transmitter 271
. . . . . . . . . . . . .
SECTION 4

03 SIENNA_U (L/O 0207)
2542003 MY SIENNA (OM45410U)
Before making these checks, make sure
you have followed the correct starting pro-
cedure given in “How to start the engine”
in Section 3 and that you have sufficient
fuel. If your vehicle is equipped with the
engine immobiliser system, also check
whether the other keys will start the en-
gine. If they work, your key may be bro-
ken. Have the key checked at your Toyota
dealer. If none of your keys work, the
system is possibly broken. Call your
Toyota dealer. (See “Keys (with engine
immobiliser system)” in Section 12.)
If the engine is not turning over or is
turning over too slowly—1. Check that the battery terminals are tight and clean.
2. If the battery terminals are O.K., switch on the interior light.
3. If the light is out, dim or goes out when the starter is cranked, the battery
is discharged. You may try jump start-
ing. See “(c) Jump starting” for further
instructions.
If the light is O.K., but the engine still will
not start, it needs adjustment or repair.
Call a Toyota dealer or qualified repair
shop.NOTICE
Do not pull or pushstart the ve-
hicle. It may damage the vehicle or
cause a collision when the engine
starts. Also the threeway catalytic
converter may overheat and become a
fire hazard.
If the engine turns over at its normal
speed but will not start— 1. Turn the ignition key to “ACC” or “LOCK” and try starting the engine
again.
2. If the engine does not start, check that all the pushon connectors are tight.
(For example, connectors at the spark
plugs, ignition coil and/or distributor)
3. If the connectors are O.K., the engine may be flooded because of repeated
cranking. See “(b) Starting a flooded
engine” for further instructions. If the engine will not start, your engine
may be flooded because of repeated
cranking.
If this happens, turn the key to “START”
with the accelerator pedal held down.
Keep the key and accelerator pedal these
positions for 15 seconds and release
them. Then try starting the engine with
your foot off the accelerator pedal.
If the engine does not start after 15 se-
conds of cranking, release the key, wait
a few minutes and try again.
If the engine still will not start, it needs
adjustment or repair. Call a Toyota dealer
or qualified repair shop for assistance.
NOTICE
Do not crank for more than 30 se-
conds at a time. This may overheat
the starter and wiring systems.
If your vehicle will not start—
(a) Simple checks
(b) Starting a flooded engine

03 SIENNA_U (L/O 0207)
2552003 MY SIENNA (OM45410U)
To avoid serious personal injury and
damage to your vehicle which might re-
sult from battery explosion, acid burns,
electrical burns, or damaged electronic
components, these instructions must be
followed precisely.
If you are unsure about how to follow this
procedure, we strongly recommend that
you seek the help of a competent me-
chanic or towing service.
CAUTION
Batteries contain sulfuric acid
which is poisonous and corrosive.
Wear protective safety glasses when
jump starting, and avoid spilling
acid on your skin, clothing, or ve-
hicle.
If you should accidentally get acid
on yourself or in your eyes, remove
any contaminated clothing and flush
the affected area with water imme-
diately. Then get immediate medical
attention. If possible, continue to
apply water with a sponge or cloth
while en route to the medical office.
The gas normally produced by a
battery will explode if a flame or
spark is brought near. Use only
standardized jumper cables and do
not smoke or light a match while
jump starting.
Warning: Battery posts, terminals
and related accessories contain lead
and lead compounds, chemicals
known to the State of California to
cause cancer and reproductive
harm. Wash hands after handling.
NOTICE
The battery used for boosting must
be 12 V. Do not jump start unless you
are sure that the booster battery is
correct.
JUMP STARTING PROCEDURE1. If the booster battery is installed in another vehicle, make sure the vehicles
are not touching. Turn off all unneces-
sary lights and accessories.
2. If required, remove all the vent plugs from the booster and discharged batter-
ies. Lay a cloth over the open vents
on the batteries. (This helps reduce the
explosion hazard, personal injuries and
burns.)
3. If the engine in the vehicle with the booster battery is not running, start it
and let it run for a few minutes. During
jump starting, run the engine at about
2000 rpm with the accelerator pedal
lightly depressed.
(c) Jump starting

03 SIENNA_U (L/O 0207)
2562003 MY SIENNA (OM45410U)
Discharged
batteryBooster
battery
Positive
terminal
(“+” mark) Positive terminal
(“+” mark)
Jumper
cable
4. Make the cable connections in the or-
der a, b, c, d.
a. Connect the clamp of the positive
(red) jumper cable to the positive (
)
terminal on the discharged battery.
b. Connect the clamp at the other end
of the positive (red) jumper cable to
the positive (
) terminal on the booster
battery.
Jumper cable
Discharged
battery Booster
battery
Negative
terminal (“–” mark)
c. Connect the clamp of the negative
(black) jumper cable to the negative ()
terminal on the booster battery.
d. Connect the clamp at the other end
of the negative (black) jumper cable to
a solid, stationary, unpainted, metallic
point of the vehicle with the discharged
battery.
The recommended connecting point is
shown in the following illustration:Connecting point
Do not connect the cable to or near
any part that moves when the engine
is cranked.
CAUTION
When making the connections, to
avoid serious injury, do not lean over
the battery or accidentally let the
jumper cables or clamps touch any-
thing except the correct battery termi-
nals or the ground.

03 SIENNA_U (L/O 0207)
2572003 MY SIENNA (OM45410U)
5. Start your engine in the normal way.After starting, run it at about 2000 rpm
for several minutes with the accelerator
pedal lightly depressed.
6. Carefully disconnect the cables in the exact reverse order: the negative cable
and then the positive cable.
7. Carefully dispose of the battery cover cloths—they may now contain sulfuric
acid.
8. If removed, replace all the battery vent plugs.
If the cause of your battery discharging is
not apparent (for example, lights left on),
you should have it checked at your Toyota
dealer. If your engine stalls while driving...
1. Reduce your speed gradually, keeping a straight line. Move cautiously off the
road to a safe place.
2. Turn on your emergency flashers.
3. Turn the ignition key to “ACC” or “LOCK”, and try starting the engine
again.
If the engine will not start, see “If your
vehicle will not start”.
CAUTION
If the engine is not running, the pow-
er assist for the brakes and steering
will not work so steering and braking
will be much harder than usual.
If your engine coolant temperature
gauge indicates overheating, if you ex-
perience a loss of power, or if you hear
a loud knocking or pinging noise, the
engine has probably overheated. You
should follow this procedure... 1. Pull safely off the road, stop the ve- hicle and turn on your emergency
flashers. Put the transmission in “P”
and apply the parking brake. Turn off
the air conditioning if it is being used.
2. If coolant or steam is boiling out of the radiator or reservoir, stop the engine.
Wait until the steam subsides before
opening the hood. If there is no coolant
boiling over or steam, leave the engine
running and make sure the electric
cooling fan is operating. If it is not,
turn the ignition off.
CAUTION
To help avoid personal injury, keep
the hood closed until there is no
steam. Escaping steam or coolant is
a sign of very high pressure.
If your engine stalls while
driving If your vehicle overheats

03 SIENNA_U (L/O 0207)
2582003 MY SIENNA (OM45410U)
3. Look for obvious coolant leaks from theradiator, hoses, and under the vehicle.
However, note that water draining from
the air conditioning is normal if it has
been used.
CAUTION
When the engine is running, keep
hands and clothing away from the
moving fan and engine drive belts.
4. If the coolant is leaking, stop the en-gine immediately. Call a Toyota dealer
for assistance.
5. If there are no obvious leaks, check the coolant reservoir. If it is dry, add
coolant to the reservoir while the en-
gine is running. Fill it about half full.
CAUTION
Do not attempt to remove the radiator
cap when the engine and radiator are
hot. Serious injury could result from
scalding hot fluid and steam blown
out under pressure.
6. After the engine coolant temperaturehas cooled to normal, again check the
coolant level in the reservoir. If neces-
sary, bring it up to half full again. Seri-
ous coolant loss indicates a leak in the
system. You s hould have it checked as
soon as possible at your Toyota dealer. 1. Reduce your speed gradually, keeping
a straight line. Move cautiously off the
road to a safe place well away from
the traffic. Avoid stopping on the center
divider of a highway. Park on a level
spot with firm ground.
2. Stop the engine and turn on your emergency flashers.
3. Firmly set the parking brake and put the transmission in “P”.
4. Have everyone get out of the vehicle on the side away from traffic.
5. Read the following instructions thor- oughly.
CAUTION
When jacking, be sure to observe the
following to reduce the possibility of
personal injury:
Follow jacking instructions.
Do not put any part of your body
under the vehicle supported by the
jack. Otherwise, personal injury may
occur.
Do not start or run the engine while
your vehicle is supported by the
jack.
If you have a flat tire—

03 SIENNA_U (L/O 0207)
2682003 MY SIENNA (OM45410U)
CAUTION
Before driving, make sure all the
tools, jack and flat tire are securely
in place in their storage location to
reduce the possibility of personal in-
jury during a collision or sudden
braking.
If your vehicle becomes stuck in snow,
mud, sand, etc., then you may attempt
to rock the vehicle free by moving it
forward and backward.
If your vehicle is equipped with the
traction control system, turn off the
system to become unstuck. (For details,
see “Traction control system” in Sec-
tion 16.)
CAUTION
Do not attempt to rock the vehicle
free by moving it forward and back-
ward if people or objects are any-
where near the vehicle. During the
rocking operation the vehicle may
suddenly move forward or backward
as it becomes unstuck, causing injury
or damage to nearby people or ob-
jects.
NOTICE
If you rock your vehicle, observe the
following precautions to prevent dam-
age to the transmission and other
parts.
 Do not depress the accelerator ped-
al while shifting the selector lever
or before the transmission is com-
pletely shifted to forward or reverse
gear.
 Do not race the engine and avoid
spinning the wheels.
 If your vehicle remains stuck after
rocking the vehicle several times,
consider other ways such as tow-
ing.
If your vehicle becomes stuck

03 SIENNA_U (L/O 0207)
2712003 MY SIENNA (OM45410U)
CAUTION
Use extreme caution when towing ve-
hicles. Avoid sudden starts or erratic
driving maneuvers which would place
excessive stress on the emergency
towing eyelets and towing cable or
chain. The eyelets and towing cable
or chain may break and cause serious
injury or damage.
NOTICE
Use only a cable or chain specifically
intended for use in towing vehicles.
Securely fasten the cable or chain to
the towing eyelets provided.
Before towing, release the parking brake
and put the transmission in “N”. The key
must be in “ACC” (engine off) or “ON”
(engine running).
CAUTION
If the engine is not running, the pow-
er assist for the brakes and steering
will not work so steering and braking
will be much harder than usual.
You can purchase a new key at your
Toyota dealer if you can give them the
key number. If your vehicle is equipped
with the engine immobiliser system, the
dealer will also need your master key.
Vehicles with engine immobiliser system—
Even if you lose only one key, contact
your Toyota dealer to make a new key. If
you lose all your master keys, you cannot
make new keys; the whole engine immobi-
liser system must be replaced.
See the suggestion given in “Keys” in
Section 12.
If your keys are locked in the vehicle and
you cannot get a duplicate, many Toyota
dealers can still open the door for you,
using their special tools. If you must
break a window to get in, we suggest
breaking the smallest side window be-
cause it is the least expensive to replace.
Be extremely cautious to avoid cuts from
the glass.Please contact your nearest Toyota
dealer and you can purchase a new
wireless remote control transmitter.
Have the registered identification numbers
of your transmitters deleted from your ve-
hicle by your Toyota dealer as soon as
possible to avoid the possibility of theft or
an accident. Then, have the identification
number of your new transmitter registered.
At the same time, you must bring all of
the remaining transmitters to have them
registered again as well.
You can use the wireless remote control
system with the new transmitter. Contact
your Toyota dealer for detailed information.
If you lose your keys
If you lose your wireless
remote control transmitter