2003 TOYOTA 4RUNNER ECU

’03 4Runner_U (L/O 0305)
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2003 4RUNNER from Apr. ’03 Prod. (OM 35820U)
If towing is necessary, we recommend
you to have it done by your Toyota
dealer or a commercial tow truck ser-
vice.
If towing service is not available in an
emergency, your vehicle may be tempo-
rarily towed by a cable or chain se-
cured to either emergency towing eyelet
under the front of the vehicle or the
left emergency towing eyelet under the
rear of the vehicle. Use extreme caution
when towing the vehicles.
NOTICE
Only use specified towing eyelet;
otherwise your vehicle may be dam-
aged.
A driver must be in the vehicle to steer
it and operate the brakes.
Towing in this manner may be done only
on hardsurfaced roads for a short dis-
tance and at low speeds. Also, the
wheels, axles, drive train, steering and
brakes must all be in good condition.
CAUTION
Use extreme caution when towing ve-
hicles. Avoid sudden starts or erratic
driving maneuvers which would place
excessive stress on the emergency
towing eyelet and towing cable or
chain. The eyelet 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 eyelet 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).
Fourwheel drive models—On multimode
fourwheel drive models, put the multi
mode control switch knob in “H2”. On full
time fourwheel drive models, unlock the
center differential.
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.

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2003 4RUNNER from Apr. ’03 Prod. (OM 35820U)
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 with ade-
quate ventilation if you run the en-
gine.
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
page 332 in Section 72 for additional
information.Tire surface and wheel nuts
Check the tires carefully for cuts, damage
or excessive wear. See page 333 in Sec-
tion 72 for additional information. When
checking the tires, make sure no nuts are
missing, and check the nuts for loose-
ness. Tighten them if necessary.
Tire rotation
Rotate the tires according to the mainte-
nance schedule. (For scheduled mainte-
nance information, please refer to the sep-
arate “Scheduled Maintenance Guide” or
“Owner ’s Manual Supplement”.) See page
334 in Section 72 for additional informa-
tion.
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 doors including back door
operate smoothly and all latches lock se-
curely. Make sure the engine hood sec-
ondary latch secures the hood from open-
ing when the primary latch is released.
General maintenance

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2003 4RUNNER from Apr. ’03 Prod. (OM 35820U)
INSIDE THE VEHICLE
Items listed below should be checked
regularly, e.g. while performing periodic
services, cleaning the vehicle, etc.
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
Check that it has the specified free play.
Be alert for changes in steering condition,
such as hard steering or strange noise.
Seats
Check that all front seat controls such as
seat adjusters, seatback recliner, etc. op-
erate smoothly and that all latches lock
securely in any position. Check that the
head restraint move up and down smooth-
ly and that the locks hold securely in any
latched position. For foldingdown rear
seatbacks and swingup rear seat cush-
ions, 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 that the
belt webbing is not cut, frayed, worn or
damaged.
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 page 343 in Section 73 for
additional information.
Engine coolant level
Make sure the coolant level is between
the “F” and “L” lines on the seethrough
reservoir when the engine is cold. See
page 326 in 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 page 328 in
Section 72 for additional information.

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2003 4RUNNER from Apr. ’03 Prod. (OM 35820U)
Instrument panel
4. AC115V INV 15 A: AC inverter
5. FR FOG 15 A: Front fog lights
6. OBD 7.5 A: Onboard diagnosis sys-
tem
7. HEAD (LO RH) 10 A: Righthand headlight (low beam)
8. HEAD (LO LH) 10 A: Lefthand head-
light (low beam)
9. HEAD (HI RH) 10 A: Righthand head- light (high beam)
10. HEAD (HI LH) 10 A: Lefthand head- light (high beam) 11. EFI NO.2 10 A:
Multiport fuel injection
system/s equential multiport fuel injec-
tion system
12. HEATER NO.2 7.5 A: Air conditioning
system
13. AIRSUS NO.2 10 A: Rear height con-
trol air suspension
14. SEAT HEATER 25 A: Seat heaters
15. DEFOG 30 A: Rear window defogger,
multiport fuel injection system/sequen-
tial multiport fuel injection system
16. MIR HEATER 10 A: Outside rear view
mirror heater
17. DOME 10 A: Interior light, personal
lights, wireless remote control system,
door courtesy lights, rear seat audio
system, g auge and meter, vanity lights,
instrument panel lights, running board
lights, multiplex communication system
18. RADIO NO.1 20 A: Audio system, nav-
igation system
19. ECUB 10 A: Antilock brake system,
navigation system, traction control sys-
tem (twowheel drive models), active
traction control system (fourwheel
drive models), vehicle stab ility control
system, air c onditioning system, multi-
plex communication system, theft deter-
rent system 20. ALTS 7.5 A:
Charging system
21. HORN 10 A: Horns
22. A/F HEATER 15 A: No circuit
23. TRNHAZ 15 A: Turn signal lights,
emergency flashers
24. ETCS 10 A: Multiport fuel injection
system/s equential multiport fuel injec-
tion system
25. EFI 20 A: Multiport fuel injection sys-
tem/sequential multiport fuel injection
system
26. DR/LCK 20 A: Power door lock system
27. TOWING 30 A: Towing converter
28. RADIO NO.2 20 A: Audio system
29. IGN 10 A: Multiport fuel injection sys-
tem/sequential multiport fuel injection
system, antilock brake system, trac-
tion control system (twowheel drive
models), active traction control system
(fourwheel drive models), vehicle sta-
bility control system, stop light, meter
and gauge
30. SRS 10 A: SRS airbag system
31. GAUGE 7.5 A: Meter and gauge
32. STA NO.2 7.5 A: Multiport fuel injec-
tion system/sequential multiport fuel in-
jection system

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2003 4RUNNER from Apr. ’03 Prod. (OM 35820U)
33. FR WIPWSH 30 A: Windshield wipers
and washer
34. 4WD 20 A: Fourwheel drive control
system
35. D P/SEAT 30 A: Driver ’s power seat
36. P P/SEAT 30 A: Front passenger ’s
power seat
37. PWR OUTLET 15 A: Power outlets
38. RR WSH 15 A: Rear window washer,
multiplex communication system
39. ECUIG 10 A: Shift lock control sys-
tem, power windows, antilock brake
system, traction control system (two
wheel drive models), active traction
control system (fourwheel drive mod-
els), vehicle stability control system,
electric moon roof, multiplex commu-
nication system, theft deterrent system,
rear height control air suspension 40. IG1 15 A:
Antilock brake system,
traction control system (twowheel
drive models), active traction control
system (fourw heel drive models), ve-
hicle stability control system, air c ondi-
tioning system, charging system, rear
window defogger, backup lights, turn
signal lights, emergency flashers, seat
heaters, AC inverter, instrument panel
light control, auto antiglare inside rear
view mirror, SRS airbag system
41. STA 7.5 A: No circuit
42. SECU/HORN 10 A: Theft deterrent sys-
tem
43. TAIL 10 A: Tail lights, license plate
lights, parking lights, instrument panel
light control, multiport fuel injection
system/s equential multiport fuel injec-
tion system, instrument panel lights,
meter and gauge, grove box light
44. ACC 7.5 A: Power outlets, outside rear
view mirrors, audio system, navigation
system, rear seat audio system, shift
lock control system, instrument panel
lights
45. CIG 10 A: No circuit Fuses (type B)
46. HEATER 50 A: Air conditioning system
47. AIRSUS 50 A: Rear height control air
suspension
48. AM1 50 A: All components in “ACC”,
“CIG”, “IG1”, “ECUIG”, “FR WIP
WSH”, “RR WIP”, “RRWSH”, “4WD”,
and “STA” fuses
49. TOWING BRK 30 A: Trailer brake con-
troller
50. J/B 50 A: All components in “PWR
OUTLET”, “D P/SEAT”, “P P/SEAT”,
“POWER”, “TAIL” and “SECU/HORN”
fuses
51. BATT CHG 30 A: Trailer sub battery
52. TOWING 40 A: Trailer lights (tail
lights)
53. ABS MTR 40 A: Antilock brake sys-
tem, traction control system (twowheel
drive models), active traction control
system (fourw heel drive models), ve-
hicle stability control system
54. AM2 30 A: Starter system, “IGN”,
“GAUGE”, “STA NO.2” and “SRS” fuses