lexus LS400 1999 Comfort Adjustment / LEXUS 1999 LS400 OWNER'S MANUAL (OM50514U)

CHASSIS
425
CHECKING AND REPLACINGTIRES
When to replace your tires
63L006-2

CHASSIS
426

1New tread 2Tread wear indicator
3Worn tread
Replace the tires when the tread wear indicators
show. The location of the tread wear indicators is
shown by the ºTWIº or º
Dº marks molded on the
sidewall of each tire.
The tires on your Lexus have built±in 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.

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427
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 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.

CHASSIS
428Warning: 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.
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.

CHASSIS
429
INSTALLING SNOW TIRES ANDCHAINS
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.

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430
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.
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 ºSº type radial tire chains, with the
exception of radial cable chains or V±bar 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 locked±wheel braking, as use of
chains may adversely affect vehicle handling.

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431
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.

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432
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.

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433

SECTION 6 ± 4
434
SERVICE PROCEDURES AND
SPECIFICATIONS
Electrical components
Specifications434
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Checking battery condition 443
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Battery recharging precautions 451
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Checking and replacing the blade type fuses 453 . . . . .
Checking the cartridge type fuses 457
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Adding washer fluid 459
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Checking the headlight aim 459
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Replacing light bulbs 462
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SPECIFICATIONS
± FUSE LOCATIONS