2003 TOYOTA SIENNA engine

03 SIENNA_U (L/O 0207)
2252003 MY SIENNA (OM45410U)
INFORMATION BEFORE DRIVING YOUR
TOYOTA
Breakin period226
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Fuel 226
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Fuel pump shut off system 228
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Operation in foreign countries 228
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Threeway catalytic converter 229
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Engine exhaust cautions 230
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Facts about engine oil consumption 230
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Iridiumtipped spark plugs 231
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Brake system 232
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Brake pad wear limit indicators 235
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Luggage stowage precautions 235
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Roof luggage carrier 236
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Your Toyota’s identification 237
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Theft prevention labels 238
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Suspension and chassis 238
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Types of tires 239
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SECTION 2

03 SIENNA_U (L/O 0207)
2262003 MY SIENNA (OM45410U)
Drive gently and avoid high speeds.
Your vehicle does not need an elaborate
breakin. But following a few simple tips
for the first 1600 km (1000 miles) can add
to the future economy and long life of
your vehicle:
Avoid full throttle acceleration when
starting and driving.
Avoid racing the engine.
Try to avoid hard stops during the first
300 km (200 miles).
Do not drive for a long time at any
single speed, either fast or slow.
Do not tow a trailer during the first 800
km (500 miles).FUEL TYPE
Your new vehicle must use only un-
leaded gasoline.
To help prevent gas station mixups, your
Toyota has a smaller fuel tank opening.
The special nozzle on pumps with un-
leaded fuel will fit it, but the larger stan-
dard nozzle on pumps with leaded gas will
not.
At a minimum, the gasoline you use
should meet the specifications of ASTM
D4814 in the U.S.A. and CGSB 3.5M93
in Canada.NOTICE
Do not use leaded gasoline. Use of
leaded gasoline will cause the three
way catalytic converter to lose its ef-
fectiveness and the emission control
system to function improperly. Also,
this can increase maintenance costs.
OCTANE RATING
Select Octane Rating 87 (Research
Octane Number 91) or higher. For
improved vehicle performance, the use
of premium unleaded gasoline with an
Octane Rating of 91 (Research Octane
Number 96) or higher is recommended.
Use of unleaded gasoline with an octane
rating or research octane number lower
than stated above will cause persistent
heavy knocking. If it is severe, this will
lead to engine damage.
If your engine knocks...
If you detect heavy knocking even when
using the recommended fuel, or if you
hear steady knocking while holding a
steady speed on level roads, consult your
Toyota dealer.
However, now and then, you may notice
light knocking for a short time while accel-
erating or driving up hills. This is no need
of concern.
Breakin period
Fuel

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GASOLINE CONTAINING DETERGENT
ADDITIVES
Toyota recommends the use of gasoline
that contains detergent additives to
avoid buildup of engine deposits.
However, all gasoline sold in the U.S.
contains detergent additives to keep clean
and/or clean intake systems.
QUALITY GASOLINE
Automotive manufacturers in the U.S.,
Europe and Japan have developed a
specification for quality fuel named
WorldWide Fuel Charter (WWFC) that
is expected to be applied world wide.
The WWFC consists of three categories
that depend on required emission lev-
els. In the U.S., category 3 has been
adopted. The WWFC improves air quali-
ty by providing for better emissions in
vehicle fleets, and customer satisfaction
through better vehicle performance.CLEANER BURNING GASOLINE
Cleaner burning gasoline, including re-
formulated gasoline that contains oxy-
genates such as ethanol or MTBE is
available in many areas.
Toyota recommends the use of cleaner
burning gasoline and appropriately blended
reformulated gasoline. These types of gas-
oline provide excellent vehicle perfor-
mance, reduce vehicle emissions, and im-
prove air quality.
OXYGENATES IN GASOLINE
Toyota allows the use of oxygenate
blended gasoline where the oxygenate
content is up to 10% ethanol or 15%
MTBE. If you use gasohol in your
Toyota, be sure that it has an octane
rating no lower than 87.
Toyota does not recommend the use of
gasoline containing methanol.
SULFUR IN GASOLINE
If your vehicle is certified to California
Emission Regulations, the vehicle is
designed to operate on California
cleaner burning gasoline (CBG) that
contains lower sulfur. If you cannot use
California CBG, your emission control
system may suffer damage and turn on
the Malfunction Indicator Lamp.
If the malfunction is caused by the type
of fuel used, repairs may not be covered
by your warranty.
GASOLINE CONTAINING MMT
Some gasoline contain an octane en-
hancing additive called MMT (Methylcy-
clopentadienyl Manganese Tricarbonyl).
Toyota does not recommend the use of
gasoline that contains MMT. If fuel con-
taining MMT is used, your emission con-
trol system may be adversely affected.
The Malfunction Indicator Lamp on the in-
strument cluster may come on. If this hap-
pens, contact your Toyota dealer for ser-
vice.

03 SIENNA_U (L/O 0207)
2282003 MY SIENNA (OM45410U)
GASOLINE QUALITY
In a very few cases, you may experience
driveability problems caused by the partic-
ular gasoline that you are using. If you
continue to have unacceptable driveability,
try changing gasoline brands. If this does
not rectify your problem, then consult your
Toyota dealer.
NOTICE
Do not use gasohol other than
stated above. It will cause fuel sys-
tem damage or vehicle performance
problems.
 If driveab ility problems occur (poor
hot starting, vaporizing, engine
knock, etc.), discontinue the use.
 Take care not to spill gasohol dur-
ing refueling. Gasohol may cause
paint damage.
FUEL TANK CAPACITY
79 L (21 gal., 17.5 lmp. gal.) The fuel pump shut off system stops sup-
plying fuel to the engine to minimize the
risk of fuel leakage when the engine stalls
or an airbag inflates upon collision. To
restart the engine after the fuel pump shut
off system activates, turn the ignition
switch to “ACC” or “LOCK” once and start
it.
CAUTION
Inspect the ground under the vehicle
before restarting the engine. If you
find that liquid has leaked onto the
ground, it is the fuel system has
been damaged and it is in need of
repair. In this case, do not restart the
engine.
If you plan to drive your Toyota in
another country...
First,
comply with the vehicle registration
laws.
Second, confirm the availability of the cor-
rect fuel (unleaded and minimum octane
number).
Fuel pump shut off system Operation in foreign countries

03 SIENNA_U (L/O 0207)
2292003 MY SIENNA (OM45410U)
The threeway catalytic converter is an
emission control device installed in the
exhaust system.
The purpose is to reduce pollutants in the
exhaust gas.
CAUTION
Keep people and combustible mate-
rials away from the exhaust pipe
while the engine is running. The
exhaust gas is very hot.
Do not drive, idle or park your ve-
hicle over anything that might burn
easily such as grass, leaves, paper
or rags.
NOTICE
A large amount of unburned gases
flowing into the threeway catalytic
converter may cause it to overheat
and create a fire hazard. To prevent
this and other damage, observe the
following precautions:
Use only unleaded gasoline.
 Do not drive with an extremely low
fuel level; running out of fuel could
cause the engine to misfire, creat-
ing an excessive load on the three
way catalytic converter.
 Do not allow the engine to run at
idle speed for more than 20 min-
utes.
 Avoid racing the engine.
 Do not pushstart or pullstart your
vehicle.
 Do not turn off the ignition while
the vehicle is moving.
Keep your engine in good running
order. Malfunctions in the engine
electrical system, electronic ignition
system/distributor ignition system
or fuel system could cause an ex-
tremely high threeway catalytic
converter temperature.
 If the engine becomes difficult to
start or stalls frequently, take your
vehicle in for a checkup as soon
as possible. Remember, your Toyota
dealer knows your vehicle and its
threeway catalytic converter sys-
tem best.
 To ensure that the threeway cata-
lytic converter and the entire emis-
sion control system operate proper-
ly, your vehicle must receive the
periodic inspections required by the
Toyota Maintenance Schedule. For
scheduled maintenance information,
refer to the “Scheduled Maintenance
Guide” or “Owner ’s Manual Supple-
ment”.
Threeway catalytic converter

03 SIENNA_U (L/O 0207)
2302003 MY SIENNA (OM45410U)
CAUTION
Avoid inhaling the engine exhaust.
It contains carbon monoxide, which
is a colorless and odorless gas. It
can cause unconsciousness or even
death.
Make sure the exhaust system has
no holes or loose connections. The
system should be checked from
time to time. If you hit something,
or notice a change in the sound of
the exhaust, have the system
checked immediately.
Do not run the engine in a garage
or enclosed area except for the
time needed to drive the vehicle in
or out. The exhaust gases cannot
escape, making this a particularly
dangerous situation.
Do not remain for a long time in a
parked vehicle with the engine run-
ning. If it is unavoidable, however,
do so only in an unconfined area
and adjust the heating or cooling
system to force outside air into the
vehicle.
Keep the back door and quarter
windows closed while driving. An
open or unsealed back door and
quarter windows may cause exhaust
gases to be drawn into the vehicle.
To allow proper operation of your
vehicle’s ventilation system, keep
the inlet grilles in front of the wind-
shield clear of snow, leaves, or oth-
er obstructions.
If you smell exhaust fumes in the
vehicle, drive with the windows
open and the back door and quarter
windows closed. Have the cause im-
mediately located and corrected.
FUNCTIONS OF ENGINE OIL
Engine oil has the primary functions of
lubricating and cooling the inside of the
engine, and plays a major role in main-
taining the engine in proper working order.
ENGINE OIL CONSUMPTION
It is normal that an engine should con-
sume some engine oil during normal
engine operation. The causes of oil
consumption in a normal engine are as
follows.
Oil is used to lubricate pistons, piston
rings and cylinders. A thin film of oil
is left on the cylinder wall when a pis-
ton moves downwards in the cylinder.
High negative pressure generated when
the vehicle is decelerating sucks some
of this oil into the combustion chamber.
This oil as well as some part of the oil
film left on the cylinder wall is burned
by the high temperature combustion
gases during the combustion process.
Oil is also used to lubricate the stems
of the intake valves. Some of this oil
is sucked into the combustion chamber
together with the intake air and is
burned along with the fuel. High tem-
perature exhaust gases also burn the
oil used to lubricate the exhaust valve
stems.
Engine exhaust cautionsFacts about engine oil
consumption

03 SIENNA_U (L/O 0207)
2312003 MY SIENNA (OM45410U)
The amount of engine oil consumed de-
pends on the viscosity of the oil, the
quality of the oil and the conditions the
vehicle is driven under.
More oil is consumed by highspeed driv-
ing and frequent acceleration and decel-
eration.
A new engine consumes more oil, since
its pistons, piston rings and cylinder walls
have not become conditioned.
When judging the amount of oil con-
sumption, note that the oil may become
diluted and make it difficult to judge
the true level accurately.
As an example, if a vehicle is used for
repeated short trips, and consumes a nor-
mal amount of oil, the dipstick may not
show any drop in the oil level at all, even
after 1000 km (600 miles) or more. This
is because the oil is gradually becoming
diluted with fuel or moisture, making it
appear that the oil level has not changed.
The diluting ingredients evaporate out
when the vehicle is then driven at high
speeds, as on an express way, making it
appear that oil is excessively consumed
after driving at high speeds.IMPORTANCE OF ENGINE OIL LEVEL
CHECK
One of the most important points in prop-
er vehicle maintenance is to keep the en-
gine oil at the optimum level so that oil
function will not be impaired. Therefore, it
is essential that the oil level be checked
regularly. Toyota recommends that the oil
level be checked every time you refuel
the vehicle.
NOTICE
Failure to check the oil level regularly
could lead to serious engine trouble
due to insufficient oil.
For detailed information on oil level check,
see “Checking the engine oil level” in Sec-
tion 72.
Your engine is fitted with iridiumtipped
spark plugs.
NOTICE
Use only iridiumtipped spark plugs
and do not adjust gaps for your en-
gine performance smooth driveabili-
ty.
Iridiumtipped spark plugs

03 SIENNA_U (L/O 0207)
2322003 MY SIENNA (OM45410U)
The tandem master cylinder brake system
is a hydraulic system with two separate
subsystems. If either subsystem should
fail, the other will still work. However, the
pedal will be harder to press, and your
stopping distance will be longer. Also, the
brake system warning light may come on.
CAUTION
Do not drive your vehicle with only a
single brake system. Have your
brakes fixed immediately.
BRAKE BOOSTER
The brake booster uses engine vacuum to
powerassist the brakes. If the engine
should quit while you are driving, you can
bring the vehicle to a stop with normal
pedal pressure. There is enough reserved
vacuum for one or two stops—but no
more!
CAUTION
Do not pump the brake pedal if the
engine stalls. Each push on the
pedal uses up your reserved vacu-
um.
Even if the power assist is com-
pletely lost, the brakes will still
work. But you will have to push the
pedal hard, much harder than nor-
mal. And your braking distance will
be longer.
ANTILOCK BRAKE SYSTEM (with
“ABS” warning light)
The antilock brake system is designed
to help prevent lockup of the wheels
during a sudden braking or braking on
slippery road surfaces. This assists in
providing directional stability and steer-
ing performance of the vehicle under
these circumstances.
Effective way to press the ABS brake
pedal: When the antilock brake system
function is in action, you may feel the
brake pedal pulsating and hear a noise.
In this situation, to let the antilock
brake system work for you, just hold the
brake pedal down more firmly. Do not
pump the brake in a panic stop. This
will result in reduced braking performan-
ce.
The antilock brake system becomes op-
erative 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).
Depressing the brake pedal on slippery
road surfaces such as on the manhole
cover, the steel plate under the construc-
tion, joints in the bridge, etc. on a rainy
day tends to activate the antilock brake
system.
You may hear a click or motor sound in
the engine compartment for a few seconds
when the engine is started or just after
the vehicle is started. This means that the
antilock brake system is in the self
check mode, and does not indicate a mal-
function.
Brake system