2003 TOYOTA SIENNA check engine

03 SIENNA_U (L/O 0207)
652003 MY SIENNA (OM45410U)
NOTICE
Do not put unevenly weighed ob-
jects on the seat and do not stick
sharp objects (needles, nails, etc.)
into the seat.
 When cleaning the seats, do not
use organic substances (paint thin-
ner, benzine, alcohol, gasoline,
etc.). They may damage the heater
and seat surface.
 To prevent the battery from being
discharged, turn the switch off
when the engine is not running.
Toyota strongly urges that the driver and
passengers in the vehicle be properly re-
strained at all times with the seat belts
provided. Failure to do so could increase
the chance of injury and/or the severity of
injury in accidents.
Child. Use a child restraint system ap-
propriate for the child until the child be-
comes large enough to properly wear the
vehicle’s seat belts. See “Child restraint”
for details.
If a child is too large for a child restraint
system, the child s hould sit in the rear
seat and must be restrained using the
vehicle’s seat belt. According to accident
statistics, the child is safer when properly
restrained in the rear seat than in the
front seat.
If a child must sit in the front seat, the
seat belts should be worn properly. If an
accident occurs and the seat belts are not
worn properly, the force of the rapid infla-
tion of the airbag may cause death or
serious injury to the child. Do not allow the child to stand up or
kneel on either rear or front seats. An
unrestrained child could suffer serious in-
jury or death during emergency braking or
a collision. Also, do not let the child sit
on your lap. It does not provide sufficient
restraint.
Pregnant woman.
Toyota recommends the
use of a seat belt. Ask your doctor for
specific recommendations. The lap belt
should be worn securely and as low as
possible over the hips and not on the
waist.
Injured person. Toyota recommends the
use of a seat belt. Depending on the inju-
ry, first check with your doctor for specific
recommendations.
Seat belts—
—Seat belt precautions

03 SIENNA_U (L/O 0207)
1422003 MY SIENNA (OM45410U)
(a) Brake System Warning Light
This light comes on in the following cases
when the ignition key is in the “ON” posi-
tion.
When the parking brake is applied...
This light comes on for a few seconds
when the ignition key is turned to the
“ON” position even after the parking brake
is released.
When the brake fluid level is low...
CAUTION
It is dangerous to continue driving
normally when the brake fluid level is
low.
Have your vehicle checked at your
Toyota dealer in the following case:
The light does not come on even if the
parking brake is applied when the igni-
tion key is in the “ON” position.
The light does not come on even if the
ignition key is turned on with the park-
ing brake released.
A warning light turning on briefly during
operation does not indicate a problem.
CAUTION
If either of the following conditions
occurs, immediately stop your vehicle
at a safe place and contact your
Toyota dealer.
The light does not turn off even
after the parking brake is released
while the engine is running.
In this case, the brakes may not
work properly and your stopping
distance will become longer. De-
press the brake pedal firmly and
bring the vehicle to an immediate
stop.
The brake system warning light re-
mains on together with the “ABS”
warning light.
In this case, not only the antilock
brake system will fail but also the
vehicle will become extremely un-
stable during braking.
(b) Driver’s Seat Belt Reminder Light and Buzzer
This light and buzzer remind you to
buckle up the driver’s seat belt.
Once the ignition key is turned to “ON”,
the reminder light flashes and buzzer
sounds if the driver ’s seat belt is not fas-
tened. Unless the driver fastens the belt,
the light keeps flashing and the buzzer
stops after about 4 to 8 seconds.
(c) Front Passenger ’s Seat Belt Re- minder Light
This light reminds you to buckle up the
front passenger ’s seat belt.
Once the ignition key is turned to “ON”,
the reminder light flashes if a passenger
sits in the front passenger seat and does
not fastened. However, if a front passen-
ger uses an additional seat cushion, the
light may not flash even when the seat
belt is not buckled up.
If luggage load is placed on the front
passenger seat, depending on its weight
and how it is placed on the seat, builtin
sensors in the seat cushion may detect
the pressure, causing the reminder light to
come on.

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(d) Discharge Warning Light
This light warns that the battery is being
discharged.
If it comes on while you are driving, there
is a problem somewhere in the charging
system.
The engine ignition will continue to oper-
ate, however, until the battery is dis-
charged. Turn off the air conditioning,
blower, radio, etc., and drive directly to
the nearest Toyota dealer or repair shop.
NOTICE
Do not continue driving if the engine
drive belt is broken or loose.
(e) Malfunction Indicator Lamp
This lamp comes on when the ignition
key is turned to the “ON” position and
goes off after the engine starts. This
means that the warning light system is
operating properly.
If the lamp remains on, or the lamp
comes on while driving, first check the
followings.
Empty fuel tank
If the fuel tank is empty, refuel immedi-
ately.
Loose fuel tank cap
If the fuel tank cap is loose, securely
tighten it.
These cases are temporary malfunctions.
The malfunction indicator lamp will go off
after taking several driving trips.
If the lamp will not go off even after the
several trips, contact your Toyota dealer
as soon as possible.
If the fuel tank is not empty or the fuel
tank cap is not loose...
There is a problem somewhere in the
engine, emission control system, auto-
matic transmission electrical system or
warning light system itself.
Contact your Toyota dealer as soon as
possible to service the vehicle.
Emissions Inspection and Maintenance
(I/M) programs
Your vehicle may not pass a state
emission inspection if the malfunction
indicator lamp remains on. Contact your
Toyota dealer to check your vehicle’s
emission control system and OBD
(OnBoard Diagnostics) system before
taking your vehicle for the inspection.
For details, see “Emissions Inspection and
Maintenance (I/M) programs” in Section 6. (f) Low Fuel Level Warning Light
This light comes on when the fuel level
in the tank becomes nearly empty. Fill up
the tank as soon as possible.
On inclines or curves, due to the move-
ment of fuel in the tank, the low fuel level
warning light may come on earlier than
usual.
(g) Low Engine Oil Pressure Warning
Light
This light warns that the engine oil pres-
sure is too low.
If it flickers or stays on while you are
driving, pull off the road to a safe place
and stop the engine immediately. Call a
Toyota dealer or qualified repair shop for
assistance.
The light may occasionally flicker when
the engine is idling or it may come on
briefly after a hard stop. There is no
cause for concern if it then goes out when
the engine is accelerated slightly.
The light may come on when the oil level
is extremely low. It is not designed to
indicate low oil level, and the oil level
must be checked using the level dipstick.

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CHECKING SERVICE REMINDER
INDICATORS (except the low fuel level
warning light and low windshield
washer fluid level warning light)
1. Apply the parking brake.
2. Open one of the doors. The open door warning light should
come on.
3. Close the door. The open door warning light should go
off.
4. Turn the ignition key to “ACC”. The SRS warning light should come on.
It goes off after about 6 seconds.
5. Turn the ignition key to “ON”, but do not start the engine.
All the service reminder indicators ex-
cept the open door warning light, open
power sliding door warning light and
SRS warning light should come on. The
“ABS” warning light, “VSC” warning
light, low tire pressure warning lights,
“TRAC OFF” indicator light and slip in-
dicator light go off after a few seconds. 6. Vehicles with a power sliding door sys-
tem:
Open the sliding door.
The open power sliding door warning
light should come on.
Close the sliding door.
The open power sliding door warning
light should go off.
If any service reminder indicator or warn-
ing buzzer does not function as described
above, have it checked by your Toyota
dealer as soon as possible.

03 SIENNA_U (L/O 0207)
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CAUTION
Always keep your foot on the brake
pedal while stopped with the engine
running. This prevents the vehicle
from creeping.
NOTICE
Do not hold the vehicle on an up-
grade with the accelerator pedal. It
can cause the transmission to over-
heat. Always use the brake pedal or
parking brake.
The traction control system automatical-
ly helps prevent the spinning of front
wheels when the vehicle is started or
accelerated on slippery road surfaces.
When the ignition key is turned to “ON”,
the system automatically turns on.
CAUTION
Under certain slippery road condi-
tions, full traction of the vehicle and
power against front 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 when the
engine is started or just after the vehicle
is started. This means that the traction
control system is in the selfcheck mode,
but does not indicate a malfunction.
Traction control system

03 SIENNA_U (L/O 0207)
1542003 MY SIENNA (OM45410U)
“VSC” warning light
This light warns that there is a problem
somewhere in the traction control system
or the vehicle skid control system.
The light will come on when the ignition
key 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 ignition key is turned to “ON”.
The warning light remains on after the
ignition key is turned to “ON”.
The warning light comes on while driv-
ing.
The vehicle skid control system helps
provide integrated control of the sys-
tems such as an antilock brake sys-
tem, brake assist system, traction con-
trol, 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 abrupt
steering wheel operation occurs.
This system activates 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 when the
engine is started or just after the vehicle
is started. This means that the system is
in the selfcheck mode but does not indi-
cate a malfunction.
Vehicle skid control system

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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

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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