2003 TOYOTA SIENNA ECU

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2672003 MY SIENNA (OM45410U)
Steel wheels
Aluminum wheels
10. Reinstall the wheel ornament.1. Put the wheel ornament into position.
Steel wheel models, align the cutout of
the wheel ornament with the valve stem
as shown. 2. Then tap it firmly with the side or heel of your hand to snap it into place.
CAUTION
Take due care in handling the orna-
ment to avoid unexpected personal
injury.
11. Check the air pressure of the re- placed tire.
Adjust the air pressure to the specification
designed in Section 8. If the pressure is
lower, drive slowly to the nearest service
station and fill to the correct pressure.
Do not forget to reinstall the tire inflation
valve cap as dirt and moisture could get
into the valve core and possibly cause air
leakage. If the cap is missing, have a new
one put on as soon as possible.
12. Restow all the tools, jack and flat tire securely.
As soon after changing wheels as pos-
sible, tighten the wheel nuts to the torque
specified in Section 8 with a torque
wrench. Have a technician repair the flat
tire.
Vehicles with a spare tire of the same
size as the installed tires—
13. Push the tire pressure warning sys- tem reset switch.
Initial adjustment of the tire pressure
warning system is necessary after you
have replaced your tires or wheels. See
“Tire pressure warning system” in Section
16.
—Reinstalling wheel ornament —After changing wheels

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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

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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

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2832003 MY SIENNA (OM45410U)
If you are a skilled doityourself mechan-
ic, the Toyota service manuals are recom-
mended. Please be aware that doityour-
self maintenance can affect your warranty
coverage. See “Owner ’s Warranty Informa-
tion Booklet” or “Owner ’s Manual Supple-
ment” for the details.Listed below are the general maintenance
items that should be performed as fre-
quently as specified. In addition to check-
ing the items listed, if you notice any
unusual noise, smell or vibration, you
should investigate the cause or take your
vehicle to your Toyota dealer or a quali-
fied service shop immediately. It is recom-
mended that any problem you notice be
brought to the attention of your dealer or
the qualified service shop for their advice.
CAUTION
Make these checks only where ade-
quate ventilation can be obtained if
you run the engine.
OUTSIDE THE VEHICLE
Items listed below should be performed
from time to time, unless otherwise
specified.
Tire pressure
Check the pressure with a gauge every
two weeks, or at least once a month. See
Section 72 for additional information.Tire surface and wheel nuts
Check the tires carefully for cuts, damage
or excessive wear. See Section 72 for
additional information. When checking the
tires, make sure no nuts are missing, and
check the nuts for looseness. Tighten
them if necessary.
Tire rotation
Rotate the tires according to the mainte-
nance schedule. (For scheduled mainte-
nance information, please refer to the
“Scheduled Maintenance Guide” or “Own-
er ’s Manual Supplement”.) See Section
72 for additional information.
Fluid leaks
Check underneath for leaking fuel, oil, wa-
ter or other fluid after the vehicle has
been parked for a while. If you smell fuel
fumes or notice any leak, have the cause
found and corrected immediately.
Doors and engine hood
Check that all the doors operate smoothly
and all latches lock securely. Make sure
the engine hood secondary latch secures
the hood from opening when the primary
latch is released.
INSIDE THE VEHICLE
Items listed below should be checked
regularly, e.g. while performing periodic
services, cleaning the vehicle, etc.
General maintenance

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Lights
Make sure the headlights, stop lights, tail
lights, turn signal lights, and other lights
are all working. Check headlight aim.
Service reminder indicators and warning
buzzers
Check that all service reminder indicators
and warning buzzers function properly.
Steering wheel
Be alert for changes in steering condition,
such as hard steering or strange noise.
Seats
Check that all seat controls such as seat
adjusters, seatback recliner, etc. operate
smoothly and that all latches lock securely
in any position. Check that the head re-
straints move up and down smoothly and
that the locks hold securely in any latched
position. For foldingdown rear seatbacks
and detachable rear seats, check that the
latches lock securely.
Seat belts
Check that the seat belt system such as
buckles, retractors and anchors operate
properly and smoothly. Make sure the belt
webbing is not cut, frayed, worn or dam-
aged.Accelerator pedal
Check the pedal for smooth operation and
uneven pedal effort or catching.
Brake pedal
Check the pedal for smooth operation and
that the pedal has the proper clearance.
Check the brake booster function.
Brakes
At a safe place, check that the brakes do
not pull to one side when applied.
Parking brake
Check that the pedal has the proper travel
and that, on a safe incline, your vehicle
is held securely with only the parking
brake applied.
Automatic transmission “Park” mecha-
nism
On a safe incline, check that your vehicle
is held securely with the selector lever in
“P” position and all brakes released.
IN THE ENGINE COMPARTMENT
Items listed below should be checked
from time to time, e.g. each time when
refueling.
Washer fluid
Make sure there is sufficient fluid in the
tank. See Section 73 for additional in-
formation.
Engine coolant level
Make sure the coolant level is between
the “FULL” and “LOW” lines on the see
through reservoir when the engine is cold.
See Section 72 for additional information.
Radiator, condenser and hoses
Check that the front of the radiator and
condenser are clean and not blocked with
leaves, dirt, or insects. See Section 72
for additional information.
Battery electrolyte level
Your Toyota has a maintenance free bat-
tery. You do not have to add distilled wa-
ter. For longer life of the battery, however,
see Section 73 for additional information.
Brake fluid level
Make sure the brake fluid level is correct.
See Section 72 for additional information.

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1. Open the hood. Unplug the connec-tor. Remove the rubber cover.
If the connector is tight, wiggle it.2. Release the bulb retaining spring and remove the bulb. Install a new
bulb and the bulb retaining spring.
To install a bulb, align the tabs of the
bulb with the cutouts of the mounting
hole.
“TOP PULL” mark
3. Install the rubber cover with the “TOP PULL” mark upward, and fit it
securely on the boss. Then plug in
the connector.
Make sure the rubber cover fits securely
on the bulb base and the mounting body.
Aiming is not necessary after replacing
the bulb. When aiming adjustment is nec-
essary, contact your Toyota dealer.
—Headlights

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Instrument panel
9. HORN 10 A: Horn, theft deterrent sys-
tem
10. HAZARD 10 A: Emergency flashers
11. AM2 30 A: “IGN” and “STARTER”
fuses
12. HEAD (LH) 15 A: Lefthand headlight
(high beam)
13. RADIO NO.1 20 A: Car audio system
Instrument panel
14. DOME 10 A: Clock, personal lights,
vanity mirror lights, door courtesy
lights, luggage compartment light, open
door warning light, ignition switch light,
theft deterrent system, daytime running
light system, interior lights, air condi-
tioning system, wireless remote control,
garage door opener
15. ECUB 10 A: Cruise control system,
SRS warning light, power sliding door
16. FOG 20 A: Front fog lights
17. ABS NO.3 25 A: Vehicle skid control
system 18. ABS NO.2 25 A:
Vehicle skid control
system
19. HLP LH (LO) 10 A: Lefthand head-
light (low beam)
20. HLP RH (LO) 10 A: Righthand head-
light (low beam)
21. ABS NO.4 5 A: Vehicle skid control
system
22. HEATER 10 A: Air conditioning system,
rear window defogger
23. GAUGE 10 A: Gauges and meters,
service reminder indicators and warning
buzzers (except discharge and open
door warning light), power windows,
daytime running light system, backup
lights, power sliding door, auto anti
glare inside rear view mirror, compass
24. WIPER 25 A: Windshield wipers and
washer, rear window wiper and washer
25. MIRRORHEATER 10 A: Multiport fuel
injection system/sequential multiport
fuel injection system, outside rear view
mirror defogger
26. ECUIG 15 A: Cruise control system,
antilock brake system, vehicle skid
control system, locking with wireless
remote control system, theft deterrent
system

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27. IGN 5 A: Gauges and meters, charging
system, SRS airbag system, seat belt
pretensioners, multiport fuel injection
system/s equential multiport fuel injec-
tion system
28. STOP 15 A: Stop lights, cruise control
system, highm ounted stoplight, tail
lights
29. TAIL 10 A: Parking lights, front side
marker lights, license plate lights, tail
lights, power sliding door
30. PWRVENT 15 A: Power rear quarter
windows
31. OBD 7.5 A: Onboard diagnosis sys-
tem
32. PWROUTLET 15 A: Power outlets
33. STARTER 5 A: Multiport fuel injection
system/s equential multiport fuel injec-
tion system
34. DOOR 25 A: Power door lock system,
theft deterrent system
35. PANEL 7.5 A: Gauge and meter, car
audio system, clock, air conditioning
system, instrument p anel light control,
rear window defogger, electronically
controlled automatic transmission sys-
tem, emergency flashers, parking
lights, seat heaters, power rear quarter
windows, power sliding door 36. TURN 7.5 A:
Turn signal lights, emer-
gency flashers
37. RADIO NO.2 7.5 A: Car audio system
38. CIG 15 A: Cigarette lighter, clock, pow-
er rear view mirror controls, SRS air-
bag system, seat belt pretensioners,
backup lights, theft deterrent system,
air conditioning system
39. A /C 5 A: Front air conditioning system
Fuses (type B)
40. CDS 40 A: Electric cooling fans
41. RDI 40 A: Electric cooling fans
42. CDS 30 A: Electric cooling fans
43. RDI 30 A: Electric cooling fans
44. MAIN 40 A: Daytime running light sys-
tem, “HLP RH (LO)” and “HLP LH
(LO)” fuses
45. R /R A /C 40 A: Rear air conditioning
system
46. HTR 50 A: Front air conditioning sys-
tem
47. PWR SLD 30 A: Power sliding door
(left side)
48. Rr CLR 40 A: Rear air conditioning
system
49. DEF 30 A: Rear window defogger,
“MIRRORHEATER” fuse 50. PWR 30 A:
Power windows, electric
moon roof, power seat, power sliding
door (right side), “PWRVENT” fuse
51. AM1 40 A: “CIG”, “RADIO NO.2”,
“ECUIG”, “WIPER”, “HEATER”,
“GAUGE” and “TURN” fuses
Fuses (type C)
52. ALT 140 A: Charging system, “FL
ABS”, “INP”, “HTR” and “R/R A/C”
fuses
53. INP 100 A: “AM1” and “DEF” fuses
54. FL ABS 60 A: Antilock brake system