maintenance Lexus GS450h 2007 Using the hands-free system (for cellular phone) / LEXUS 2007 GS450H THROUGH JUNE 2006 PROD. (OM30727U) Service Manual

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Maintenance and care
Initializing the tire pressure warning system
■The tire pressure warning system must be initialized in the following
circumstances:
● When r
otating the tires on vehicles differing with front and rear tire
inflation pressures.
● When changing the tir
e inflation pressure by changing traveling
speed or load weight, etc.
● When changing the tir
e size.
When the tire pressure warning sys tem is initializ
ed, the current tire
inflation pressure is set as the pressure benchmark.
■ Ho
w to initialize the tire pressure warning system
Park the vehicle in safe place and turn the po
wer switch to “OFF”
mode.
While the vehicle is moving, initialization is not performed.
Adjust the tire inflation pressure to the specified cold tire inflation
pressure level. ( P. 4 8 7 )
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 power switch to “IG-ON” mode.
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STEP2
STEP3

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Push and hold the tire pressure
warning reset switch until the tire
pressure warning light blinks
slowly three times and the mes-
sage “PRESSURE INITIAL”
appears on the multi-information
display

.
Wait for a few minutes with the “IG-ON” mode, and then turn
power switch to “OFF” mode.
Registering and selecting ID codes
■ Registering ID codes
2 sets of tire pressure warning va lv
e and transmitter ID codes can be
registered. Once a second set of tire s (winter tires etc.) is registered at
“2nd”, you can switch b etween tire set settings si mply by pressing the
tire pressure warning select switch.
There are 2 settings:
“MAIN” position: The ID code of the tir
e pressure warning valve and
transmitter on the tires originally inst alled on the vehicle is registered.
“2nd” position: The code is not registered. When you replace a new set
of tir
es, purchase tire pressure warning valves and transmitters from
your Lexus dealer and have the new ID code registered by your Lexus
dealer.
STEP4
STEP5

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Maintenance and care
■Selecting ID codes
When replacing tires, make sure to select the ID code set that matches
the ne
w tire set. If the incorrect ID code is selected, the tire pressure
warning system will not operate properly. After a certain period of
time, the tire pressure warning li ght comes on after blinking for 1
minute to indicate a system malfunction.
“MAIN”
“2nd”
■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.
■Tire life
Any tire over 6 years old must be checked by a qualified technician even if they
h
ave 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 (245/40R18, P245/40R18 and 245/40ZR18 tires)
Generally, low profile tires will wear more rapidly and tire grip performance will be
r
educed on snowy and/or icy roads when co mpared to standard tires. Be sure to
use snow tires or snow chains on snowy and/or icy roads and drive carefully at a
speed appropriate for road and weather conditions.

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■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. 385, 492).
■Tire types
1 Summer tires
Summer 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 in adequate 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 icy 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 74 )
■Initializing the tire pressure warning system
Initialize the tires with the tire inflatio n pressure adjusted to the specified level.

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Maintenance and care
■If you push the tire pressure reset switch accidentally
If initialization is performed, adjust the tire inflation pressure to the specified level
and initialize the system again.
■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 warning light does
not flash and the setting message does not appear on the multi-information dis-
play.
●After driving for a certain period of time since the initialization has been com-
pleted, the warning light flashes.
■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.

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■Tire pressure warning system certificationFor vehicles sold in the U.S.A.
NOTE:
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 th e 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
NOTE:
Operation is subject to the following two conditions: (1) this device may not cause
interference, and (2) this device must accept any interference, including interfer-
ence that may cause undesired operation of the device.

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Maintenance and care
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 tread wear.
●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 push the reset switch without first ad justing 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, tires or the tire pressure warning valve and
transmitter, contact your Lexus dealer as the tire pressure warning valve and
transmitter may be damaged if not handled correctly.
●When replacing tires, make sure also to replace the tire pressure warning valve
and transmitter grommets.
■Do not use puncture sealant sprays to repair flats
Puncture sealant sprays may damage tire pressure tire pressure warning valves and
transmitters.

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NOTICE
■Driving on rough roads
Take particular care when driving on roads with loose surfaces or potholes.
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 (245/40R18, P245/40R18 and 245/40ZR18 tires)
Low profile 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 hot 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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Maintenance and care
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. 4 8 7)

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■Tire inflation pressure check interval
You should check tire inflation pressure every two weeks, or at least once a month.
If equipped, 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 tire 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 v
alve and check for leak-
age.
Reinstall the tire valve cap.
STEP1
STEP2
STEP3
STEP4
STEP5
STEP6