1998 Lexus LS400 lexus LS400 1998 Engine / LEXUS 1998 LS400 OWNER'S MANUAL (OM50498U)

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.

CHASSIS
243
CHECKING AND REPLACING
TIRES
When to replace your tires
63L006-2
1
New tread 2
Tread wear indicator
3
Worn tread
Replace the tires when the tread wear indicators show. The
location of the tread wear indicators is shown by the ”TWI” or
”
Δ” marks molded on the sidewall of each tire.
The tires on your Lexus have builtin tread wear indicators to help
you know when the tires need replacement. When the tread depth
wears to 1.6 mm (0.06 in.) or less, the indicators will appear. If you
can see the indicators in two or more adjacent grooves, the tire
should be replaced.
The effectiveness of snow tires is lost if the tread wears down
below 4 mm (0.16 in.).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.

CHASSIS
244
Uniform tire quality grading
This information has been prepared in accordance with
regulations issued by the National Highway Traffic 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.
These quality grades are molded on the sidewall.
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 A, B, C The traction grades, from highest to lowest, are
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.Warning: The traction grade assigned to this tire is based on braking
(straight ahead) traction tests and does not include cornering
(turning) traction.
Temperature A, B, C The temperature grades are A (the highest),
B, and C, representing the tire’s resistance to the generation of heat
and its ability to dissipate heat when tested under controlled
conditions on a specified indoor laboratory test wheel. Sustained
high temperature can cause the material of the tire to degenerate and
reduce tire life, and excessive temperature can lead to sudden tire
failure. The grade C corresponds to a level of performance which all
passenger car tires must meet under the Federal Motor Vehicle
Safety Standard No. 109. Grades B and A represent higher levels of
performance on the laboratory test wheel than the minimum required
by law.
Warning: The temperature grade of this tire established for a tire that
is properly inflated and not overloaded. Excessive speed,
underinflation, or excessive loading, either separately or in
combination, can cause heat buildup and possible tire failure.

CHASSIS
245
Tire selection
When replacing a tire, use only the same size and construction
as originally installed and with the same or greater load capacity.
Using any other size or type of tire may seriously affect handling,
ride, speedometer/odometer calibration, ground clearance, and
clearance between the body and tires or snow chains.
Do not mix radial, belted, or conventional tires on your vehicle.
Do not use tires or wheels other than the manufacturer’s
recommended size.
It can cause dangerous handling characteristics, resulting in loss of
control. If you need to change from conventional tires to radial tires
or vice versa, replace them as a set.
INSTALLING SNOW TIRES AND
CHAINS
When to use snow tires or chains
Snow tires or chains are recommended when driving on snow or
ice.
On wet or dry roads, conventional or radial tires provide better
traction than snow or studded tires.
Snow tire selection
If you need snow tires, select the same size, construction and load
capacity as the original tires on your Lexus.
Do not use tires other than stated above. Since your vehicle has
radial tires as original equipment, make sure your snow tires also
have radial construction. Do not install studded tires without first
checking local regulations for possible restrictions.
Snow tire installation
Snow tires should be installed on all wheels.
Installing snow tires on the rear wheels only can lead to an excessive
difference in road grip capability between the front and rear tires
which could cause loss of vehicle control.

CHASSIS
246
CAUTION
Do not drive with the snow tires incorrectly inflated.
Never drive over 120 km/h (75 mph) with any type of snow
tires.
Tire chain selection
Regulations regarding the use of tire chains vary according to
location or type of road. Always check the local regulations
before installing chains.
Use SAE Class ”S” type radial tire chains, with the exception of
radial cable chains or Vbar type chains.
Chain installation
Install the chains on the rear tires as tightly as possible. Do not
use tire chains on the front tires. Retighten chains after driving
0.5 1.0 km (1/4 1/2 mile).
When installing chains on your tires, carefully follow the
instructions of the chain manufacturer.
CAUTION
Do not exceed 50 km/h (30 mph) or the chain
manufacturer’s recommended speed limit, whichever is
lower.
Drive carefully avoiding bumps, holes, and sharp turns,
which may cause the vehicle to bounce.
Avoid sharp turns or lockedwheel braking, as use of
chains may adversely affect vehicle handling.

CHASSIS
247
REPLACING WHEELS
When to replace your wheels
If you have wheel damage such as bending, cracks or heavy
corrosion, the wheel should be replaced.
If you fail to replace damaged wheels, a tire may slip off a wheel or
they may cause loss of handling control.
Replacement with used wheels is not recommended as they may
have been subjected to rough treatment or high mileage and could
fail without warning. Also, bent wheels which have been
straightened may have hidden structural damage and therefore
should not be used. Never use an inner tube in a leaking wheel which
is designed for a tubeless tire.
Wheel selection
When replacing wheels, care should be taken to ensure that they
are equivalent to those removed in load capacity, diameter, rim
width, and offset.
Correct replacement wheels are available at your Lexus dealer.
A wheel of a different size or type may adversely affect handling,
wheel and bearing life, brake cooling, speedometer/odometer
calibration, stopping ability, headlight aim, bumper height, vehicle
ground clearance, and tire or snow chain clearance to the body and
chassis.
ALUMINUM WHEEL
PRECAUTIONS
After driving your vehicle the first 1600 km (1000 miles), check
that the wheel nuts are tight.
If you have rotated, repaired, or changed your tires, check that the
wheel nuts are still tight after driving 1600 km (1000 miles).
When using tire chains, be careful not to damage the aluminum
wheels.
Use only the Lexus wheel nuts and wrench designed for your
aluminum wheels.
When balancing your wheels, use only Lexus balance weights or
equivalent and a plastic or rubber hammer.
As with any wheel, periodically check your aluminum wheels for
damage. If damaged, replace immediately.
SUSPENSION AND CHASSIS
CAUTION
Do not modify the suspension/chassis with lift kits, spacers,
springs, etc. It can cause dangerous handling characteristics,
resulting in loss of control.

SECTION 6 4
248
SERVICE PROCEDURES AND
SPECIFICATIONS
Electrical components
Specifications 249. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking battery condition 253. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Battery recharging precautions 257. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking and replacing the blade type fuses 258. . . . . . . . . . . . . . . . . . . .
Checking the cartridge type fuses 260. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adding washer fluid 261. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking the headlight aim 261. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing light bulbs 264. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ELECTRICAL COMPONENTS
249
SPECIFICATIONS
FUSE LOCATIONS
64L0061
1
Engine compartment
2
Driver’s side instrument panel FUSES
64L0071
Driver’s side instrument panel