2003 TOYOTA SIENNA wiring

03 SIENNA_U (L/O 0207)
742003 MY SIENNA (OM45410U)
This indicator comes on when the igni-
tion key is turned to the “ACC” or
“ON” position. It goes off after about
6 seconds. This means the front seat
belt pretensioners are operating proper-
ly.
This warning light system monitors the
airbag sensor assembly, front airbag sen-
sors, side airbag sensors, front seat belt
pretensioner assemblies, inflators, warning
light, interconnecting wiring and power
sources. (For details, see “Service remain-
der indicators and warning buzzers” in
Section 15.)The front seat belt pretensioner system
mainly consists of the following compo-
nents and their locations are shown in the
illustration.1. Front airbag sensors
2. SRS warning light
3. Front seat belt pretensioner assemblies
4. Airbag sensor assembly
The front seat belt pretensioners are con-
trolled by the airbag sensor assembly. The
airbag sensor assembly consists of a saf-
ing sensor and airbag sensor. When the front seat belt pretensioners are
activated, an operating noise may be
heard and a small amount of smokelike
gas may be released. This gas is harm-
less and does not indicate that a fire is
occurring.
Once the front seat belt pretensioners
have been activated, the seat belt retrac-
tors remain locked.
CAUTION
Do not modify, remove, strike or open
the front seat belt pretensioner as-
semblies, airbag sensor or surround-
ing area or wiring. Doing so may
cause sudden operation of the front
seat belt pretensioners or disable the
system, which could result in death
or serious personal injury.
Failure to follow these instructions
can result in death or serious inju-
ries. Consult your Toyota dealer
about any repairs and modifications.

03 SIENNA_U (L/O 0207)
762003 MY SIENNA (OM45410U)
The SRS (Supplemental Restraint Sys-
tem) front airbags are designed to pro-
vide further protection for the driver
and front passenger in addition to the
primary safety protection provided by
the seat belts.
In response to a severe frontal impact,
the SRS front airbags work together with
the seat belts to help reduce injury by
inflating. The SRS front airbags help to
reduce injuries mainly to the driver ’s or
front passenger ’s head or chest caused by
directly hitting the steering wheel or dash-
board. The front passenger airbag is acti-
vated even with no passenger in the front
seat.
Be sure to wear your seat belt properly.Your vehicle is equipped with a crash
sensing and diagnostic module, which will
record the use of the seat belt restraint
system by the driver and front pass
enger
when the SRS airbags are inflated.
CAUTION
The driver or front passenger who is
too close to the steering wheel or
dashboard during airbag deployment
can be killed or seriously injured.
Toyota strongly recommends that:
The driver sit as far back as pos-
sible from the steering wheel while
still maintaining control of the ve-
hicle.
The front passenger sit as far back
as possible from the dashboard.
All vehicle occupants be properly
restrained using the available seat
belts.
This indicator comes on when the igni-
tion key is turned to the “ACC” or
“ON” position. It goes off after about
6 seconds. This means the SRS front
airbags are operating properly.
This warning light system monitors the
airbag sensor assembly, front airbag sen-
sors, side airbag sensors, front seat belt
pretensioner assemblies, inflators, warning
light, interconnecting wiring and power
sources. (For details, see “Service remind-
er indicators and warning buzzers” in Sec-
tion 15.)
SRS driver airbag and front
passenger airbag

03 SIENNA_U (L/O 0207)
842003 MY SIENNA (OM45410U)
Your vehicle is equipped with a crash
sensing and diagnostic module, which will
record the use of the seat belt restraint
system by the driver and front passenger
when the SRS side airbags are inflated.
CAUTION
SRS side airbags inflate with consid-
erable force. To avoid potential death
or serious injury when they inflate,
the driver and front passenger must:
Wear their seat belts properly.
Remain properly seated with their
back upright and against the seat at
all times.This indicator comes on when the igni-
tion key is turned to the “ACC” or
“ON” position. It goes off after about
6 seconds. This means the SRS side
airbags are operating properly.
This warning light system monitors the
airbag sensor assembly, front airbag sen-
sors, side airbag sensor, front seat belt
pretensioner assemblies, inflators, warning
light, interconnecting wiring and power
sources. (For details, see “Service remind-
er indicators and warning buzzers” in Sec-
tion 15.)The SRS side airbag system may not
activate if the vehicle is subjected to a
collision from the side at certain
angles, or a collision to the side of the
vehicle body other than the passenger
compartment as shown in the illustra-
tion.
The SRS side airbags are designed to
inflate when the passenger compartment
area suffers a severe impact from the
side.
For the safety of all occupants, always
wear your seat belts properly.

03 SIENNA_U (L/O 0207)
1452003 MY SIENNA (OM45410U)
(k) SRS Warning Light
This light will come on when the igni-
tion key is turned to the “ACC” or
“ON” position. After about 6 seconds,
the light will go off. This means the
system of the airbag and front seat belt
pretensioners are operating properly.
The warning light system monitors the air-
bag sensor assembly, front airbag sen-
sors, side airbag sensor, front seat belt
pretensioner assemblies, inflators, warning
light, interconnecting wiring and power
sources.
If either of the following conditions occurs,
this indicates a malfunction somewhere in
the parts monitored by the warning light
system. Contact your Toyota dealer as
soon as possible to service the vehicle.
The light does not come on when the
ignition key is turned to the “ACC” or
“ON” position or remains on.
The light comes on or flashes while
driving.(l) Vehicle Skid Control System/Traction
Control System Warning Light
This light warns that there is a problem
somewhere in the vehicle skid control sys-
tem or traction 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. (m) Low Windshield Washer Fluid Level
Warning Light
The light warns that the windshield washer
fluid level is too low. Add washer fluid at
your earliest opportunity. (For instructions,
see “Adding washer fluid” in Section 73.)
(n) Low Tire Pressure Warning Light
This light warns that the tire pressure of
any one of the tires is critically reduced.
The light comes on when the ignition key
is turned to the “ON” position. It goes off
after a few seconds. This indicates that
the low tire pressure warning system is
functioning properly.
If the light comes on while driving, adjust
tire pressure to the specified level. (See
“Tires” in Section 8.) After the tire pres-
sure is adjusted, the light should go off
after driving at about more than 30 km/h
(19 mph) for some time. If the light still
remains, have the low tire pressure warn-
ing system checked at your Toyota dealer.
(o) Key Reminder Buzzer
This buzzer reminds you to remove the
key when you open the driver ’s door with
the ignition key in the “ACC” or “LOCK”
position.

03 SIENNA_U (L/O 0207)
2432003 MY SIENNA (OM45410U)
NOTICE
Do not crank for more than 30 se-
conds at a time. This may overheat
the starter and wiring systems.
 Do not race a cold engine.
 If the engine becomes difficult to
start or stalls frequently, have the
engine checked immediately.
Always slow down in gusty crosswinds.
This will allow you much better control.
Drive slowly onto curbs and, if pos-
sible, at a right angle. Avoid driving
onto high, sharpedged objects and
other road hazards. Failure to do so
can lead to severe tire damage result-
ing in tire bursts.
Drive slowly when passing over bumps
or travelling on a bumpy r oad. Other-
wise, the impact could cause severe
damage to the tires and/or wheels.
When parking on a hill, turn the front
wheels until they touch the curb so
that the vehicle will not roll. Apply the
parking brake, and place the transmis-
sion in “P”. If necessary, block the
wheels.
Washing your vehicle or driving through
deep water may get the brakes wet. To
see whether they are wet, check that
there is no traffic near you, and then
press the pedal lightly. If you do not
feel a normal braking force, the brakes
are probably wet. To dry them, drive
the vehicle cautiously while lightly
pressing the brake pedal with the park-
ing brake applied. If they still do not
work safely, pull to the side of the road
and call a Toyota dealer for assistance.
CAUTION
Before driving off, make sure that
the parking brake is fully released
and the parking brake reminder
light is off.
Do not leave your vehicle unat-
tended while the engine is running.
Do not rest your foot on the brake
pedal while driving. It can cause
dangerous overheating, needless
wear, and poor fuel economy.
To drive down a long or steep hill,
reduce your speed and downshift.
Remember, if you ride the brakes
excessively, they may overheat and
not work properly.
Be careful when accelerating, up-
shifting, downshifting or braking on
a slippery surface. Sudden accelera-
tion or engine braking could cause
the vehicle to spin or skid.
Tips for driving in various
conditions

03 SIENNA_U (L/O 0207)
2482003 MY SIENNA (OM45410U)
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.

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