Page 419 of 573

4187-3. Do-it-yourself maintenance
IS350/250_U (OM53758U)
CAUTION
■When inspecting or replacing tires
Observe the following precautions to prevent accidents.
Failure to do so may cause damage to parts of the drivetrain as well as dangerous han-
dling characteristics, which may lead to an accident resulting in death or serious injury.
●Do not mix tires of different makes, models or tread patterns.
Also, do not mix tires of remarkably different treadwear.
●Do not use tire sizes other than those recommended by Lexus.
●Do not mix differently constructed tires (radial, bias-belted or bias-ply tires).
●Do not mix summer, all season and snow tires.
●Do not use tires that have been used on another vehicle.
Do not use tires if you do not know how they were used previously.
●Do not tow if your vehicle has a compact spare tire installed.
■When initializing the tire pressure warning system
Do not operate the tire pressure warning reset 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 pressu re is low, or it may come on when the tire
inflation pressure is actually normal.
■Caution regarding interference with electronic devices
●Users of any electrical medical device other than implanted pacemakers and
implanted cardiac defibrillators should cons ult the manufacturer of the device for
information about its operation un der the influence of radio waves.
Radio waves could have unexpected effe cts on the operation of such medical
devices.
●People with implanted pacemakers or car-
diac defibrillators should not come within 17.7
in. (450 mm) of the tire pressure warning sys-
tem initiators. The radio waves may affect the
operation of such devices.
Page 422 of 573

4217-3. Do-it-yourself maintenance
7
Maintenance and care
IS350/250_U (OM53758U)
Tire valve
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 gauge gradations.
If the tire inflation pressure is not at the recommended level, adjust the pres-
sure.
If you add too much air, press the center of the valve to deflate.
After completing the tire inflation pressure measurement and adjustment,
apply soapy water to the valve and check for leakage.
Put the tire valve cap back on.
■Tire inflation pressure check interval
You should check tire inflation pressure ev ery two weeks, or at least once a month.
Do not forget to check the spare.
■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 drivetrain
If a tire needs frequent inflating, have it checked by your Lexus dealer.
Inspection and adjustment procedure
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Page 423 of 573

4227-3. Do-it-yourself maintenance
IS350/250_U (OM53758U)
■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 or 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 pressure that is
even just a few pounds off can affect ride quality and handling.
●Do not reduce tire inflation pressure after driv ing. It is normal for 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 balanced.
CAUTION
■Proper inflation is critical to save tire performance
Keep your tires properly inflated. Otherwis e, the following conditions may occur and
result in an accident causing death or serious injury:
●Excessive wear
●Uneven wear
●Poor handling
●Possibility of blowouts result ing from overheated tires
●Poor sealing of the tire bead
●Wheel deformation and/or tire separation
●A greater possibility of tire damage from road hazards
NOTICE
■When inspecting and adjust ing tire inflation pressure
Be sure to put the tire valve caps back on.
Without the valve caps, dirt or moisture could get into the valve and cause air leakage,
which could result in an accident. If the caps are lost, replace them as soon as possible.
Page 428 of 573
4277-3. Do-it-yourself maintenance
7
Maintenance and care
IS350/250_U (OM53758U)
●Flathead screwdriver
●Small flathead screwdriver
●Lithium battery CR2032
Take out the mechanical key.
Remove the cover.
To prevent damage to the key, wrap the
tip of the screwdriver with tape.
Remove the depleted battery.
Insert a new battery with the “+” termi-
nal facing up.
Electronic key battery
Replace the battery with a new one if it is depleted.
You will need the following items:
Replacing the battery
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Page 430 of 573
4297-3. Do-it-yourself maintenance
7
Maintenance and care
IS350/250_U (OM53758U)
Turn the engine switch off.
Open the Fuse box cover.
Engine compartment (type A fuse box)
Push the tab in and lift the lid off.
Engine compartment (type B fuse box)
Push the tab in and lift the lid off.
Driver’s side instrument panel
Remove the lid.
Checking and replacing fuses
If any of the electrical components do not operate, a fuse may have blown. If
this happens, check and replace the fuses as necessary.
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2
Page 437 of 573
4367-3. Do-it-yourself maintenance
IS350/250_U (OM53758U)
■Front turn signal lights (vehicles with discharge headlights) To ensure enough space to per-
form work, turn the steering
wheel to rotate the front wheel
away from the bulb to be
replaced.
Remove the 2 fender liner clips.
Turn the steering wheel to the left
when replacing the right side light
bulb, and turn the steering wheel to
the right when replacing the left side
light bulb.
To take out the lower clip, turn the
head of the clip to unlock it, then
remove it by pulling.
Unfasten the clamp, and pull back
the fender liner.
When unfastening the clamp, wrap
the tip of the screwdriver with tape to
protect the vehicle from damage.
Turn the bulb base counterclock-
wise.
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2
3
Page 440 of 573
4397-3. Do-it-yourself maintenance
7
Maintenance and care
IS350/250_U (OM53758U)
■Rear turn signal lightsOpen the trunk, and remove the
2 covers and 2 screws.
When removing the cover, wrap the
tip of the screwdriver with tape to
protect the vehicle from damage.
Push and pull the light unit toward
the rear of the vehicle as shown in
the illustration to remove it.
Apply protective tape to the periph-
eral of the light un it installation sur-
face on the vehicle body, such as the
rear bumper, to protect the vehicle
from damage.
Pushing on the portion A in the illus-
tration toward the rear of the vehicle
will make disengagement of the tabs
easier.
Turn the bulb base counterclock-
wise.
Remove the light bulb.
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Page 447 of 573
446
IS350/250_U (OM53758U)8-1. Essential information
Press the switch.
All the turn signals will flash.
To turn them off, press the switch once
again.
■Emergency flashers
If the emergency flashers are used for a long time while the engine is not operating, the
battery may discharge.
Emergency flashers
The emergency flashers are used to warn other drivers when the vehicle has
to be stopped in the road due to a breakdown, etc.