maintenance Lexus IS250 2008 Using the air conditioning system and defogger / LEXUS 2008 IS250 (OM53699U) Service Manual

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4-3. Do-it-yourself maintenance
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Maintenance and care
■How to initialize the tire pressure warning system
To initialize the system, use the satellite switch. ( P. 245)
Park the vehicle in safe plac e and turn the “ENGINE START
STOP” switch OFF.
While the vehicle is moving, initialization is not performed.
Adjust the tire inflation pressure to the specified cold tire inflation
pressure level. ( P. 415)
Make sure to adjust the tire pressure to the specified cold tire inflation
pressure level. The tire pressure warning system will operate based on
this pressure level.
Turn the “ENGINE START STOP” switch to IGNITION ON
mode.
The tire inflation pressure initial-
ization setting display
Continue to press  or  until the
initialization setting display
appears.
It may take several minutes to com-
plete the setting. Wait for several
minutes before turning the
“ENGINE START STOP” switch to
OFF if necessary.
Recording tire inflation pressure
settings
Press and hold the “ON/OFF” but-
ton until the tire pressure warning
light blinks slowly 3 times and the
message “PRESSURE INITIAL”
showing that the initial setting is
complete is displayed on the multi-
information display.
Wait for a few minutes with the IGNITION ON mode, and then
turn the “ENGINE START STOP” switch OFF.
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Registering and selecting ID codesTo select tire pressure warning valve and transmitter ID codes, use the
satellite switch. ( P. 245)
■ Registering ID codes
2 sets of tire pressure warning valve and transmitter ID codes can be
registered. Once a second set of ti res is registered at “2ND”, you can
switch between tire set settings simply by pressing the tire pressure
warning select switch.
There are 2 settings:
“MAIN” position: The ID code of the tire pressure warning valve and
transmitter on the tires originally inst alled on the vehicle is registered.
“2ND” position:The ID code is not registered. When you replace a
new set of tires, purchase tire pres sure warning valves and transmitters
from your Lexus dealer and have th e new ID code registered by your
Lexus dealer.
■ Selecting ID codes
When replacing tires, make sure to select the ID code set that matches
the new tire set. If the tire pressure select switch is set to the wrong tire
setting, the tire pressure warnin g system will not operate properly.
After driving for about 20 minutes, the tire pressure warning light
comes on after blinking for 1 minu te to indicate a system malfunction.
Tire pressure warning valve and
transmitter ID code settings dis-
play
Press  or  repeatedly until the
setting display appears.
Switching ID codes
Press the “ON/OFF” button to
switch between “MAIN” and
“2ND” ID codes.

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Maintenance and care
■When to replace your vehicle’s tires
Tires should be replaced if:
●You have tire damage such as cuts, splits, cracks deep enough to expose the
fabric or bulges indicating internal damage
●A tire goes flat repeatedly or cannot be properly repaired due to the size or
location of a cut or other damage
If you are not sure, consult with your Lexus dealer.
■Replacing tires and wheels
If the ID code of the tire pressure warn ing valve and transmitter is not registered,
the tire pressure warning system will not work properly. After driving for about 20
minutes, the tire pressure warning light comes on after blinking for 1 minute to indi-
cate a system malfunction.
■Tire life
Any tire over 6 years old must be checked by a qualified technician even if they
have seldom or never been used or damage is not obvious.
■If the tread wears down below 0.16 in. (4 mm) on snow tires
The effectiveness of snow tires is lost.
■Low profile tires (models not equipped with 16-inch tires)
Generally, low profile tires will wear more rapidly and tire grip performance will be
reduced on snowy and/or icy roads when co mpared to standard tires. Be sure to
use snow tires or tire chains
* on snowy and/or icy roads and drive carefully at a
speed appropriate for road and weather conditions.
*: Tire chains cannot be mounted on 18-inch tires.
■Maximum load of tire
Check that the maximum load of the replaced tire is greater than 1 /2 of the Gross
Axle Weight Ratings (GAWR) of either the front axle or the rear axle, whichever is
greater.
As for the maximum load of the tire, see the load limit at maximum cold tire inflation
pressure mentioned on the sidewall of the tire, and as for the Gross Axle Weight
Ratings (GAWR), see the Certification Label. (
P. 3 1 6 , 4 2 4 ) .

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4-3. Do-it-yourself maintenance
■Tire types
1 Summer tiresSummer tires are high-speed performance tires best suited to highway driving
under dry conditions. Since summer tires do not have the same traction perfor-
mance as snow tires, summer tires are inadequate for driving on snow-covered
or icy roads. For driving on snow-covered roads or icy roads, the use of snow tires
is recommended. When installing snow tires, be sure to replace all four tires.
2 All season tires All season tires are designed to provide better traction in snow and to be ade-
quate for driving in most winter conditions , as well as for use year round. All sea-
son tires, however, do not have adequa te traction performance compared with
snow tires in heavy or loos e snow. Also, all season tires fall short in acceleration
and handling performance compared with summer tires in highway driving.
3Snow tires For driving on snow-covered roads or ic y roads, we recommend using snow tires.
If you need snow tires, select tires of the same size, construction and load capac-
ity as the originally installed tires. 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 loca l regulations for possible restriction.
Snow tires should be installed on all wheels. ( P. 1 8 3 )
■Initializing the tire pressure warning system
Initialize the tires with the tire inflatio n pressure adjusted to the specified level.
■When the initialization of the tire pressure warning system has failed
Initialization can be completed in a few minutes. However, in the following cases,
the settings have not been recorded and the system will not operate properly. If
repeated attempts to record tire inflation pressure settings are unsuccessful, have
the vehicle inspected by your Lexus dealer.
●When operating the tire pressure warnin g reset switch, the tire pressure warn-
ing light does not flash 3 times and the setting message does not appear on the
multi-information display.
●After carrying out the initialization proc edure, the tire pressure warning light
blinks for 1 minute then stays on after driving for about 20 minutes.

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Maintenance and care
■Routine tire inflation pressure checks
The tire pressure warning system does not replace routine tire inflation pressure
checks. Make sure to check tire inflation pressure as part of your routine of daily
vehicle checks.
■Tire pressure warning system certificationFor vehicles sold in the U.S.A.
This device complies with Part 15 of the FCC Rules. Operation is subject to the fol-
lowing two conditions: (1) this device may not cause harmful interference, and (2)
this device must accept any interference received, including interference that may
cause undesired operation.
NOTICE:
This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to
provide reasonable protection against harmful interference in a residential installa-
tion. This equipment generate s, uses and can radiate radio frequency energy and, if
not installed and used in accordance with the instructions, may cause harmful inter-
ference to radio communications. However, there is no guarantee that interference
will not occur in a particular installation. If this equipment does cause harmful inter-
ference to radio or television reception, which can be determined by turning the
equipment off and on, the user is encouraged to try to correct the interference by
one or more of the following measures:
●Reorient or relocate the receiving antenna.
●Increase the separation between the equipment and receiver.
●Connect the equipment into an outlet on a circuit different from that to which
the receiver is connected.
●Consult the dealer or an experienced radio/TV technician for help.
FCC WARNING:
Changes or modifications not expressly approved by the party responsible for
compliance could void the user's authority to operate the equipment.
For vehicles sold in Canada
Operation is subject to the following two conditions: (1) this device may not cause
interference, and (2) this device must a ccept any interference, including interfer-
ence that may cause undesired operation of the device.

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4-3. Do-it-yourself maintenance
CAUTION
■When inspecting or replacing tires
Observe the following precautions to prevent accidents. Failure to do so may cause
damage to parts of the drive train, as well as dangerous handling characteristics,
which may lead to fatal or injury accidents.
●Do not mix tires of different makes, models, tread patterns or treadwear.
●Do not use tire sizes other than those recommended by Lexus.
●Do not mix radial, bias-belted, or bias-ply tires.
●Do not mix summer, all season and winter tires.
■When initializing the tire pressure warning system
Do not press the satellite switch without first adjusting the tire inflation pressure to
the specified level. Otherwise, the tire pressure warning light may not come on
even if the tire inflation pressure is low, or it may come on when the tire inflation
pressure is actually normal.
NOTICE
■Repairing or replacing tires, wheels and tire pressure warning valves and trans-
mitters
When removing or fitting the wheels, tire s or the tire pressure warning valve and
transmitter, contact your Lexus dealer as the tire pressure warning valve and trans-
mitter may be damaged if not handled correctly.
■To avoid damaging the tire pressu re warning valves and transmitters
Do not use liquid sealants on flat tires.

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Maintenance and care
NOTICE
■Driving on rough roads
Take particular care when driving on roads with loose surfaces or pot holes.
These conditions may cause losses in tire inflation pressure, reducing the cushion-
ing ability of the tires. In addition driving on rough roads may cause damage to the
tires themselves, as well as the vehicle’s wheels and body.
■Low profile tires and wheels
Wheels with profile tires like 17- and 18-inch tires may cause greater damage than
usual to the tire wheel when receiving impact from the road surface. Therefore pay
attention to the following:
●Be sure to use proper tire inflation pressure. If tires are under-inflated, they may
be damaged more severely.
●Avoid pot holes, uneven pavement, curbs and other road hazards.
Failure to do so can lead to severe tire and wheel damage.
■If tire inflation pressures become low while driving
Do not continue driving, or your tires and/or wheels may be ruined.

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4-3. Do-it-yourself maintenance
Tire inflation pressure
■Tire inflation pressure
The recommended cold tire inflation pressure and tire size is dis-
played on the tire and loading information label. ( P. 415)

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4-3. Do-it-yourself maintenance
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Maintenance and care
■Tire inflation pressure check interval
You should check tire inflation pressure every two weeks, or at least once a month.
Do not forget to check the spare.
■Inspection and adjustment procedure
Ti r e v a l v e
Tire pressure gauge
Remove the tire valve cap.
Press the tip of the tire pressure gauge onto the tire valve.
Read the pressure using the graduations of the gauge.
If the tire inflation pressure is not within the recommended lev-
els, adjust the pressure.
If you add too much air, press the center of the valve to lower.
After completing the tire inflation pressure measurement and
adjustment, apply soapy water to the valve and check for leak-
age.
Reinstall the tire valve cap.
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4-3. Do-it-yourself maintenance
■Effects of incorrect tire inflation pressure
Driving with incorrect tire inflation pressure may result in the following:
●Reduced fuel efficiency
●Reduced driving comfort and tire life
●Reduced safety
●Damage to the drive train
If a tire needs frequent refilling, have it checked by your Lexus dealer.
■Instructions for checking tire inflation pressure
When checking tire inflation pressure, observe the following:
●Check 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 mile or 1.5 km, you will get an accurate cold tire inflation pressure
reading.
●Always use a tire pressure gauge.
The appearance of the tire can be misleading. In addition, tire inflation pressures
that are even just a few pounds off can degrade ride and handling.
●Do not bleed or reduce tire inflation pressure after driving. It is normal for the
tire inflation pressure to be higher after driving.
●Never exceed the vehicle capacity weight.
Passengers and luggage weight should be placed so that the vehicle is bal-
anced.