2003 Lexus GX470 air condition

MAINTENANCE
399
Brake fluid level
Make sure the brake fluid level is correct. See page 430 for
additional information.
Engine oil level
Check the level on the dipstick with the engine turned off and
the vehicle parked on a level spot. See page 419 for
additional
information.
Power steering fluid level
Check the level through the reservoir. The level should be in
the “HOT” or “COLD” range depending on the fluid
temperature. See page 431 for additional information.
Exhaust system
If you notice any change in the sound of the exhaust or smell
exhaust fumes, have the cause located and corrected
immediately. (See “Engine exhaust caution” on page 298.)
DOES YOUR VEHICLE NEED REPAIRING?
Be on the alert for changes in performance and sounds, and
visual tip −offs that indicate service is needed. Some important
clues are:
 Engine missing, stumbling, or pinging
 Appreciable loss of power
 Strange engine noises
 A fluid leak under the vehicle (However, water dripping from
the air conditioning after use is normal.)
 Change in exhaust sound (This may indicate a dangerous
carbon monoxide leak. Drive with the windows open and
have the exhaust system checked immediately.)
 Flat−looking tires, excessive tire squeal when cornering,
uneven tire wear
 Vehicle pulls to one side when driving straight on a level
road
 Strange noises related to suspension movement
 Loss of brake effectiveness, spongy feeling brake pedal,
pedal almost touches floors, vehicle pulls to one side when
braking
 Engine coolant temperature continually higher than normal

ENGINE
417
FACTS ABOUT ENGINE OILCONSUMPTION
Functions of engine oil
Engine oil has the primary function of lubricating and cooling
the inside of the engine, and plays a major role in maintaining
the engine in proper working order.
Engine oil consumption
It is normal that an engine should consume 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 piston
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 temperature exhaust gases also burn the oil used to
lubricate the exhaust valve stems. The amount of engine oil consumed depends on the
viscosity of the oil, the quality of the oil and the way the
vehicle is driven.
More oil is consumed by high
−speed driving and frequent
acceleration and deceleration.
A new engine consumes more oil, since its pistons, piston rings
and cylinder walls have not become conditioned.
When judging the amount of oil consumption, keep in
mind that the oil may have become diluted, making it
difficult to judge the true level accurately.
For example, if a vehicle is used for repeated short trips and
consumes a normal 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 expressway, making it appear
that oil is excessively consumed after driving at high speeds.

CHASSIS
433
CAUTION
Keep your tire pressure properly. Otherwise, the
following conditions may occur and cause an accident
resulting in death or serious injuries.
Low tire pressure (underinflation) —
 Excessive wear
 Uneven wear
 Poor handling
 Possibility of blowouts from overheated tire
 Poor sealing of the tire bead
 Wheel deformation and/or tire separation
High tire pressure (overinflation) —
 Poor handling
 Excessive wear at the center of the tire tread
 A greater possibility of tire damage from road
hazards
The following instructions for checking tire pressure should be
observed:
The pressure should be checked only when the tires are
cold. If your vehicle has been parked for at least 3 hours
and has not been driven for more than 1.5 km or 1 mile since,
you will get an accurate cold tire pressure reading.
 Always use a tire pressure gauge. The appearance of the
tire can be misleading. Besides, tire pressures that are even
just a few pounds off can degrade ride and handling. 
Do not bleed or reduce tire pressure after driving. It is
normal for the tire pressure to be higher after driving.
 Never exceed the vehicle capacity weight. The
passengers and luggage weight should be located so that
the vehicle is balanced.
 Be sure to reinstall the tire valve caps. Without the valve
caps, dirt or moisture could get into the valve core and cause
air leakage. If the caps have been lost, have new ones put
on as soon as possible.

CHASSIS
435
If you have tire damage such as cuts, splits, cracks deep
enough to expose the fabric, or bulges indicating internal
damage, the tire should be replaced.
If a tire often goes flat or cannot be properly repaired due to the
size or location of a cut or other damage, it should be replaced.
If you are not sure, consult with your Lexus dealer.
If an air loss occurs while driving, do not continue driving with
a deflated tire. Driving even a short distance can damage a tire
beyond repair.
Any tires which are over 6 years old must be checked by
a qualified technician even if damage is not obvious.
Tires deteriorate with age even if they have never or seldom
been used.
This also applies to the spare tire and tires stored for future use.
Uniform tire quality grading
This information has been prepared in accordance with
regulations issued by the National Highway T
raffic Safety
Administration of the U.S. Department of Transportation.
It provides the purchasers and/or prospective purchasers
of Lexus vehicles with information on uniform tire quality
grading.
Your Lexus dealer will help answer any questions you may
have as you read this information.
DOT quality grades All passenger vehicle tires must
conform to Federal Safety Requirements in addition to
these grades. Quality grades can be found where
applicable on the tire sidewall between tread shoulder and
maximum section width. For example: Treadwear 200
Traction AA Temperature A
Treadwear − The treadwear grade is a comparative rating
based on the wear rate of the tire when tested under controlled
conditions on a specified government test course. For
example, a tire graded 150 would wear one and a half (1 − 1/2)
times as well on the government course as a tire graded 100.
The relative performance of tires depends upon the actual
conditions of their use, however, and may depart significantly
from the norm due to variations in driving habits, service
practices and differences in road characteristics and climate.
Traction AA, A, B, C − The traction grades, from highest to
lowest, are AA, A, B and C, and they represent the tire’s ability
to stop on wet pavement as measured under controlled
conditions on specified government test surfaces of asphalt
and concrete. A tire marked C may have poor traction
performance.

ELECTRICAL COMPONENTS
444
 Driver’s side instrument panel
No.FUSEAMPERECIRCUIT
1 SPARE10Spare fuse
2 ALT140
Charging system and all
components in “AM1”,
“HEATER”, “CDS FAN”, “FR
FOG”, “DEFOG”, “AIR SUS”,
“AC115V INV”, “SEAT HEATER”,
“BATT CHG”, “BRAKE CTRL”
and “TOWING” fuses
3 SPARE15Spare fuse
4 HEATER50Air conditioning system
5 AIR
SUS50Rear height control air suspen-
sion
6 AM150
All components in “ACC”, “CIG”,
“IG1”, “FR WIP −WSH”, “RR
WIP”, “RR WSH”, “DIFF”,
“TEMS” and “STA” fuses
7 BRAKE
CTRL30Trailer brake controller
8 J/B50
All components in “P FR P/W”,
“P RR P/W”, “D RR P/W”, “D
P/SEAT”, “P P/SEAT”, “TAIL”,
“PANEL” and “POWER OR
TI&TE” fuses
9 BATTCHG30Trailer sub battery
10 TOWING40Trailer lights
11 CDS FAN20Electric cooling fan
12 RR A/C30Rear air conditioning system

ELECTRICAL COMPONENTS
445
No.FUSEAMPERECIRCUIT
13 MIR
HEATER10Outside rear view mirror defog-
ger
14 STOP10
Stop lights, high m ounted
stoplight, shift lock control
system, vehicle skid control
system, electronic m odulated
suspension, rear height control
air suspension, multiport fuel
injection system/sequential
multiport fuel injection system
15 AC115V
INV15Power outlet (115 VAC)
16 FR FOG15Front fog lights
17 OBD7.5On −board diagnosis system
18 HEAD
(LO RH)10Right− hand headlight (low beam)
19 HEAD
(LO LH)10Left− hand headlight (low beam)
20 HEAD
(HI RH)10Right− hand headlight (high
beam)
21 HEAD
(HI LH)10Left− hand headlight (high beam)
22 EFI NO.210Multiport fuel injection system/
sequential multiport fuel injection
system
23 HEATER
NO.27.5Air conditioning system
24 DEFOG30Rear window defogger
No.FUSEAMPERECIRCUIT
25 AIRSUSNO.210Rear height control air suspen-
sion
26 SEAT
HEATER20Seat heaters
27 DOME10
Ignition switch light, interior
lights, personal lights, foot
lights, running board lights,
door courtesy lights, inside
door handle lights,
multi− information display
28 RADIO
NO.120Car audio system, navigation
system
29 ECUB10
Multiplex communication
system, vehicle skid control
system, wireless remote
control system, inside rear
view mirror, air conditioning
system, electronic modulated
suspension, driving position
memory system, power
windows, moon roof
30 ECUB NO.210Theft deterrent system
31 ABS
MTR40
Anti −lock brake system,
vehicle skid control system,
active traction control system,
brake assist system
32 AM230Starting system, all components
in “IGN”, “SRS”, “GAUGE” and
“ST2” fuses

ELECTRICAL COMPONENTS
446
No.FUSEAMPERECIRCUIT
33 ABSSOL50
Anti −lock brake system,
vehicle skid control system,
active traction control system,
brake assist system
34 ALTS7.5Charging system
35 MAYDAY7.5Lexus link system
36 HORN10Horns
37 TRNHAZ15Turn signal lights
38 ETCS10Electronic throttle control system
39 EFI20Multiport fuel injection
system/sequential multiport fuel
injection system
40 D FR P/W20Power window
41 DR/LCK25Power door lock
42 TOWING30Towing converter
43 RADIO
NO.230Car audio system, navigation
system
44 IGN10
Multiport fuel injection
system/sequential multiport fuel
injection system, vehicle skid
control system
45 SRS10SRS airbag system
46 GAUGE7.5Gauges and meters
47 ST27.5Multiport fuel injection
system/sequential multiport fuel
injection system
No.FUSEAMPERECIRCUIT
48 FR
WIPWSH30Windshield wipers, windshield
washer
49 TEMS20Electronic modulated suspen-
sion
50 DIFF20Four−wheel drive system
51 RR WIP15Rear window wiper
52 D P/SEAT30Driver’s power seats
53 P P/SEAT30Front passenger’s power seats
54 PWR
OUTLET15Power outlet (12 VDC)
55 IG1 NO.210Rear air conditioning system, in-
side rear view mirror
56 RR WSH15Rear window washer
57 ECUIG10
Shift lock control system, power
windows, outside rear view
mirror defogger, anti −lock brake
system, active traction control
system, vehicle skid control
system, air conditioning system,
navigation system, power
windows, moon roof, Lexus link
system, tilt and telescopic
steering, multi −information
display, driving position
memory system
58 IG110
Air conditioning system, back −up
lights, rear window defogger,
seat heaters, vehicle skid control
system

BODY
460
PROTECTING YOUR VEHICLEFROM CORROSION
Proper care of your Lexus can help ensure long −term
corrosion prevention.
The most common causes of corrosion to your vehicle
are:
 The accumulation of road salt, dirt and moisture in
hard−to−reach areas under the vehicle.
 Chipping of paint or undercoating caused by minor
accidents or by stones and gravel.
The following conditions will cause or accelerate
corrosion of your vehicle, so it is important to keep your
vehicle, particularly the underside, as clean as possible
and to repair any damage to paint or protective coatings
as soon as possible.
 The presence of road salt or dust control chemicals, salt in
the air near the sea coast, industrial air pollution.
 High humidity, especially at temperatures just above
freezing point.
 Certain parts of your vehicle are wet or damp for an
extended period of time, even though other parts of the
vehicle are dry.
 Components of the vehicle which are prevented from
quick−drying due to lack of proper ventilation are exposed
to high ambient temperature. To help prevent corrosion on your Lexus, follow these
guidelines:
Keep your vehicle clean by regular washing.
In addition,
observe the following points.
 If you drive on salted roads in the winter or if you live near
the ocean, you should hose off the undercarriage at least
once a month to minimize corrosion.
 High pressure water or steam is effective for cleaning the
vehicle’s underside and wheel housings. Pay particular
attention to these areas as it is difficult to see all the mud and
dirt. It will do more harm than good to simply wet the mud
and debris without removing them. The lower edge of
doors, rocker panels and frame members have drain holes
which should not be allowed to clog with dirt as trapped
water in these areas can cause corrosion.
 Wash the underside of the vehicle thoroughly when winter
is over.
See “Washing and waxing” on page 461 for more tips.
Check the condition of your vehicle’ s paint and trim. If you
find any chips or scratches in the paint, touch them up
immediately to prevent corrosion from starting. If the chips or
scratches have gone through the bare metal, have a qualified
body shop make the repair.