air condition lexus LS400 1998 Engine / LEXUS 1998 LS400 (OM50498U) Service Manual

AIR CONDITIONING AND AUDIO
152
20L040
A new disc may have rough edges on its inner and outer
perimeter. Remove the rough edges by pressing the side of a
ballpoint pen or pencil against the inner and outer edges of the
disc as shown.
If you continue to play a disc with rough edges, flakes will fall on to
the signal side of the disc and cause sound skipping or other
problems.
CAUTION
Compact disc players use invisible laser beams which could
cause hazardous radiation exposure if directed outside the
unit. Be sure to operate the player correctly as instructed.

STARTING AND DRIVING
171
Cruise control failure warning
If the ”CRUISE” indicator light in the instrument cluster flashes
when using the cruise control, push the main switch to turn the
system off and then push it again to turn it on.
If any of the following conditions then occurs, there is some trouble
in the cruise control system.
The indicator light does not come on.
The indicator light flashes again.
The indicator light goes out after it comes on.
If this is the case, contact your Lexus dealer and have your Lexus
inspected.
ELECTRONICALLY MODULATED
AIR SUSPENSION
(U.S.A. ONLY)
This electronically modulated air suspension adjusts the
damping effect on the shock absorbers and the vehicle height.
This adjustment is automatically made in response to the driving
conditions to provide good riding comfort and stability in all
driving conditions.
(a) Vehicle height adjustment
31L015-3
This system maintains a stable vehicle height, regardless of
occupants and luggage weight. You can select one of the
following modes using a selector switch.

DRIVING TIPS
188Because of the added load of the trailer, your vehicle’s engine
may overheat on hot days (at temperatures over 30C [85F])
when going up a long or steep grade with a trailer. If the engine
coolant temperature gauge indicates overheating, immediately
turn off the air conditioning (if in use), pull your vehicle off the
road and stop in a safe spot. See ”If your vehicle overheats” on
page 196 of this manual.
Always place wheel blocks under both the vehicle and trailer
wheels when parking. Apply the parking brake firmly. Put the
transmission in ”P”. Avoid parking on a slope with a trailer, but
if it cannot be avoided, do so only after performing the following:
1. Apply the brakes and keep them applied.
2. Have someone place wheel blocks under both the vehicle and
trailer wheels.
3. When the wheel blocks are in place, release your brakes slowly
until the blocks absorb the load.
4. Apply the parking brake firmly.
5. Shift into ”P” and turn off the engine.When restarting out after parking on a slope:
1. With the transmission in ”P” position, start the engine. Be sure
to keep the brake pedal depressed.
2. Shift into the ”3”, ”2”, ”L” or ”R” position.
3. Release the parking brake and brake pedal and slowly pull or back
away from the wheel blocks. Stop and apply your brakes.
4. Have someone retrieve the blocks.
CAUTION
Do not exceed 72 km/h (45 mph) or the posted towing speed
limit, whichever is lower. Because instability (swaying) of
a towing vehicletrailer combination usually increases as
the speed increases, exceeding 72 km/h (45 mph) may cause
loss of control.
Slow down and downshift before descending steep or long
downhill grades. Do not make sudden downshifts.
Avoid holding the brake pedal down too long or too
frequently. This could cause the brakes to overheat and
result in reduced braking efficiency.

DRIVING TIPS
189
HOW TO SAVE FUEL AND MAKE
YOUR VEHICLE LAST LONGER
Getting more kilometer/mileage from a liter/gallon of fuel is easy
just take it easy. It will help make your vehicle last longer, too. Here
are some specific tips on how to save money on both fuel and repairs:
Keep your tires inflated at the correct pressure. Check the
pressure every two weeks, or at least once a month.
Underinflation causes tire wear and wastes fuel.
Do not carry unneeded weight in your vehicle. Excess weight
puts a heavier load on the engine, causing greater fuel
consumption.
Avoid lengthy warmup idling. Once the engine is running
smoothly, begin driving but gently. Remember, however, that
on cold winter days this may take a little longer.
Accelerate slowly and smoothly. Avoid jackrabbit starts.
Avoid long engine idling. If you have a long wait and you are
not in traffic, it is better to turn off the engine and start again later.
Avoid engine overrevving. Use a gear position suitable for the
road on which you are traveling.
Avoid continuous speeding up and slowing down.
Stopandgo driving wastes fuel.Avoid unnecessary stopping and braking. Maintain a steady
pace. Try to time the traffic signals so you only need to stop as
little as possible or take advantage of through streets to avoid
traffic lights. Keep a proper distance from other vehicles to avoid
sudden braking. This will also reduce wear on your brakes.
Avoid heavy traffic or traffic jams whenever possible.
Do not rest your foot on the brake pedal. This causes needless
wear, overheating and poor fuel economy.
Maintain a moderate speed on highways. The faster you drive,
the greater the fuel consumption. By reducing your speed, you
will cut down on fuel consumption.
Keep the front wheels in proper alignment. Avoid hitting the
curb and slow down on rough roads. Improper alignment not only
causes faster tire wear but also puts an extra load on the engine,
which, in turn, wastes fuel.
Keep the bottom of your vehicle free from mud, etc. This not
only lessens weight but also helps prevent corrosion.
Keep your vehicle tunedup and in top shape. A dirty air
cleaner, improper valve clearance, dirty plugs, dirty oil and
grease, brakes not adjusted, etc. all lower engine performance and
contribute to poor fuel economy. For longer life of all parts and
lower operating costs, keep all maintenance work on schedule,
and if you often drive under severe conditions, see that your
vehicle receives more frequent maintenance. (For scheduled
maintenance information, please refer to the separate ”Owner’s
Manual Supplement/Maintenance Schedule”.)
CAUTION

IN CASE OF AN EMERGENCY
197 B: If no steam is coming from your engine:
Leave the engine running and turn off the air conditioning. Check
the following.
Is the cooling fan operating?
Is the coolant in the acceptable range?
Is the engine drive belt O.K.?
CAUTION
When the engine is running, keep hands and clothing away
from the moving fan and engine drive belt.
Do not attempt to remove the radiator cap when the engine
and radiator are hot. Serious injury could result from
scalding hot fluid and steam blown out under pressure.
If the cooling fan is not operating or the coolant is not in the
acceptable range, turn off the engine and call your Lexus dealer.
If both conditions are O.K., after the engine coolant temperature has
cooled to normal, continue driving your vehicle.
If the engine coolant temperature does not cool down, or your
vehicle overheats again, have it checked as soon as possible by your
Lexus dealer.
IF YOU HAVE A FLAT TIRE
1. Reduce your speed gradually, keeping a straight line. Move
cautiously off the road to a safe place well away from the traffic.
Avoid stopping on the center divider of a highway. Park on a level
spot with firm ground.
2. Stop the engine and turn on your emergency flashers.
3. Firmly set the parking brake and put the transmission in ”P”.
4. Have everyone get out of the vehicle on the side away from
traffic.
5. Read the following instructions thoroughly.
NOTICE
For vehicles equipped with the height control switch, be sure to
turn the ignition switch off before jacking. If this is not done, the
vehicle height adjustment function will operate, which may
cause body damage.
CAUTION
When jacking, be sure to observe the following to reduce the
possibility of personal injury:
Follow jacking instructions.
Do not start or run the engine while your vehicle is
supported by the jack.

MAINTENANCE
217
DOES YOUR VEHICLE NEED
REPAIRING?
Be on the alert for changes in performance and sounds, and visual
tipoffs 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.)
Flatlooking 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
If you notice any of these clues, take your vehicle to your Lexus
dealer as soon as possible. It probably needs adjustment or repair.
CAUTION
Do not continue driving with the vehicle unchecked. It could
result in serious vehicle damage and possibly personal injury.

INTRODUCTION
221
DOITYOURSELF SERVICE
PRECAUTIONS
If you perform maintenance yourself, be sure to follow the
correct procedure given in this Section.
You should be aware that improper or incomplete servicing may
result in operating problems.
Performing doityourself maintenance during the warranty period
may affect your warranty coverage. Read the separate Lexus
Warranty statement for details and suggestions.
This Section gives instructions only for those items that are
relatively easy for an owner to perform. As explained in Section 5,
there are still a number of items that must be performed by a qualified
technician with special tools.
For information on tools and parts for doityourself maintenance,
see ”Parts and tools”.
Utmost care should be taken when working on your vehicle to
prevent accidental injury. Here are a few precautions that you should
be especially careful to observe:
CAUTION
When the engine is running, keep hands, clothing, and tools
away from the moving fan and engine drive belt.
(Removing rings, watches, and ties is advisable.)
Right after driving, the engine compartment the engine,
radiator, exhaust manifold and power steering fluid
reservoir, etc. will be hot. So be careful not to touch them.
Oil and other fluids may also be hot.
Do not smoke, cause sparks or allow open flames around
fuel or the battery. Their fumes are flammable.
Be extremely cautious when working on the battery. It
contains poisonous and corrosive sulfuric acid.
Do not get under your vehicle with just the body jack
supporting it. Always use automotive jack stands or other
solid supports.
Be sure the ignition is off if you work near the electric
cooling fan or radiator grille. With the ignition on, the
electric cooling fan may automatically start to run if the air
conditioning is on and/or if the coolant temperature is high.
Use eye protection whenever you work on or under your
vehicle where you may be exposed to flying or falling
material, fluid spray, etc.
NOTICE

ENGINE
229
FACTS ABOUT ENGINE OIL
CONSUMPTION
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 highspeed 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.
Importance of engine oil level check
One of the most important points in proper vehicle maintenance is
to keep the engine oil at the optimum level so that oil function will
not be impaired. Therefore, it is essential that the oil level be
checked regularly. Lexus recommends that the oil level be checked
every time you refuel the vehicle.
NOTICE

CHASSIS
242High tire pressure produces a harsh ride, handling problems,
excessive wear at the center of the tire tread, and 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 handling and ride.
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.
ROTATING TIRES
63L007-2
To equalize tire wear and help extend tire life, Lexus
recommends that you rotate your tires approximately every
12000 km (7500 miles). However, the most appropriate timing
for tire rotation may vary according to your driving habits and
road surface conditions.
The wheel assemblies must be rotated as illustrated above. If the
optional chromeplated wheels are mounted, rotate them as pattern
A. For the standard wheels, use pattern B.
When rotating tires, check for uneven wear and damage. Abnormal
wear is usually caused by incorrect tire pressure, improper wheel
alignment, outof balance wheels, or severe braking.
Before storing radial, snow or studded tires, mark the direction of
rotation and be sure to install them in the same direction when using
them again. Tires should be stored in a cool dry place.

ELECTRICAL COMPONENTS
251
No.FUSEAMPERECIRCUIT
1 TURN7.5Turn signal lights
2 WIPER20Windshield wipers
3 HEATER10
Air conditioning system,
Rear window defogger, Multiport
fuel injection system/sequential
multiport fuel injection system
4 FR FOG15Fog lights
5 ECUIG10Power steering control system,
Charging system,
Vehicle skid control system
6 PWRIG15
Automatic headlight leveling
system, Moon roof,
Headlight cleaner,
Power seat switch,
Tilt and telescopic steering, Shift
lock system
7 GAUGE10
Gauges and meters, service
reminder indicators and warning
buzzers,
Backup lights,
Vehicle skid control system,
Multiport fuel injection
system/sequential multiport fuel
injection system, Automatic
transmission system
8 IGN10SRS, Multiport fuel injection
system/sequential multiport fuel
injection system
9 RR FOG7.5No circuit
10 FUEL OPN10Fuel opener system
No.FUSEAMPERECIRCUIT
11 RR CIG15Rear cigarette lighter,
Power outlet
12 FR CIG15Front cigarette lighter, SRS
13 A/C7.5Air conditioning system
14 P RR
DOOR20Rear door lock,
Rear power window
15 STOP LP25Stop lights,
High mounted stop light
16 RADIO
NO.215
Audio system,
Outside rear view mirror,
Shift lock system,
Air conditioning system
17 PANEL7.5Instrument panel lights,
Air conditioning system, Glovebox
light, Audio system
18 STARTER7.5
Starting system,
Automatic transmission system,
Multiport fuel injection
system/sequential multiport fuel
injection system
19 TAIL7.5Tail lights, Side marker lights,
License plate lights
20 STOPS7.5
Shift lock system,
Height control system, Antilock
brake system,
Vehicle skid control system
21 RR S/HTR15No circuit
22 WASHER20Windshield washer