tire pressure Lexus GS450h 2007 Instrument cluster /

395
4-3. Do-it-yourself maintenance
4
Maintenance and care
■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 misleadi ng. 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.

396
4-3. Do-it-yourself maintenance
CAUTION
■Proper inflation is critical to save tire performance
Keep your tires properly inflated. Otherwise, the following conditions may occur
and result in an accident causing death or serious injury.
●Excessive wear
●Uneven wear
●Poor handling
●Possibility of blowouts resulting 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 adjusting tire inflation pressure
Be sure to reinstall the tire valve caps.
Without the valve caps, dirt or moisture co uld get into the valve and cause air leak-
age, which could result in an accident. If the caps have been lost, replace them as
soon as possible.

397
4-3. Do-it-yourself maintenance
4
Maintenance and care
Wheels
■When replacing wheels
The wheels of your Lexus are equipped with tire pressure warning valves and trans-
mitters that allow the tire pressure warning system to provide advanced warning in
the event of a loss in tire inflation pressure. Whenever wheels are replaced, the tire
pressure warning valves and transmitters must be switched over from the old
wheels. ( P. 3 8 4 )
If a wheel is bent, cracked or heavily corroded, it should be replaced. 
Otherwise, the tire may separate from the wheel or cause loss of handling
control.
■ 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. 
Replacement wheels are available at your Lexus dealer.
Lexus does not recommend using:
• Wheels of different sizes or types
• Used wheels
• Bent wheels that have been straightened
• Lexus wheels with after market chrome plating
■ Aluminum wheel precautions
●Use only Lexus wheel nuts and wr enches designed for use with
your aluminum wheels.
● When rotating, repairing or changi ng your tires, check that the
wheel nuts are still tight after driving 1000 miles (1600 km).
● Be careful not to damage the aluminum wheels when using tire
chains.
● Use only Lexus genuine balance weights or equivalent and a
plastic or rubber hammer when balancing your wheels.

398
4-3. Do-it-yourself maintenance
CAUTION
■When replacing wheels
●Do not use wheels that are a different size from those recommended in the
Owner’s Manual, as this may result in loss of handling control.
●Never use an inner tube in a leaking wheel which is designed for a tubeless tire.
Doing so may result in an accident, causing death or serious injury.
NOTICE
■Replacing tire pressure warning valves and transmitters
●Because tire repair or replacement may affect the tire pressure warning valves
and transmitters, make sure to have tires serviced by your Lexus dealer or other
qualified service shop. In addition, make sure to purchase your tire pressure
warning valves and transmitters at your Lexus dealer.
●Ensure that only genuine Lexus wheels are used on your vehicle. 
Tire pressure warning valves and transmitters may not work properly with non-
genuine wheels.

414
4-3. Do-it-yourself maintenance
■Passenger’s side instrument panel
FuseAmpereCircuit
1ECU-IG RH10
Electric tilt and telescopic steering,
combination switch, power seat,
smart access system with push-but-
ton start, air conditioning system,
touch screen, shift lock system, tire
pressure warning system, front/rear
stabilizer system
2FR S/HTR RH15Seat heaters, seat heaters and venti-
lators
3RH-IG7. 5
Front right door control system, rear
right door control system, seat belt
pretensioners, transmission, seat
heaters, seat heaters and ventilators
4AM215Starting system
5FR DOOR RH20Front right door control system
6RR DOOR RH20Rear right door control system
7AIR SUS20AV S
8PWR OUTLET15Po w e r o u t l e t
9CIG15Cigarette lighter

440
5-2. Steps to take in an emergency
Have the malfunction repaired immediately.After taking the specified steps to correct the suspected problem, check
that the warning light turns off.
Warning lightWarning light/DetailsCorrection procedure
Open door warning light 
(warning buzzer)
*2
A door or the trunk is not
fully closed.
Check that all doors and the
trunk are closed.
Low fuel level warning light Remaining fuel 
(Approximately 2.6 gal. [10
L, 2.2 Imp.gal.] or less)
Refuel the vehicle.
Driver’s seat belt reminder
light (warning buzzer)
*3
Warns the driver to fasten
his/her seat belt.Fasten the seat belt.
Front passenger’s seat belt
reminder light
(warning buzzer)
*3
Warns the front passenger to
fasten his/her seat belt.
Fasten the seat belt.
Tire pressure warning light
When the light comes on:
Low tire inflation pressure.Adjust the tire inflation pres-
sure.
When the light comes on after
blinking for 1 minute:
Malfunction in the tire pres-
sure warning system.
Have the system checked by
your Lexus dealer.

442
5-2. Steps to take in an emergency
■SRS warning light
This warning light system monitors the following:
●The airbag sensor assembly
●Front airbag sensors
●The curtain shield airbag sensors
●The side and curtain shield airbag sensors
●The occupant detection sensor
●The front passenger occupant classification ECU
●“AIRBAG ON” and “AIRBAG OFF” indicator lights
●The pressure sensor
●The belt tension sensor
●The seat belt buckle switches
●The driver's seat position sensor
●The inflators
●The warning light
●The interconnecting wiring and power sources
■When the tire pressure warning light comes on
Check the tire inflation pressure and adjust to the appropriate level. Pushing the tire
pressure warning reset switch does not turn off the tire pressure warning light.
■The tire pressure warning light may turn on due to natural causes
The tire pressure warning light may turn on due to natural causes such as natural air
leaks or tire inflation pressure changes caus ed by temperature. In this case, adjust-
ing the tire inflation pressure will turn off the warning light.

5
When trouble arises
443
5-2. Steps to take in an emergency
CAUTION
■If the tire pressure warning light comes on
Be sure to observe the following precautions. Failure to do so could cause loss of
vehicle control and result in death or serious injury.
●Vehicles with run-flat tires:
• Decelerate to the lowest appropriate speed as soon as possible. Do not drive
over 55 mph (90 km/h).
• Check and adjust the tire inflation pressure immediately.
• If the tire pressure warning light comes on even after tire inflation pressure
adjustment, it is probable that you have a flat tire. Have the tire replaced by
the nearest Lexus dealer.
• Avoid abrupt maneuvering and braking. If the vehicle tires deteriorate, you
could lose control of the steering wheel or the brakes.
●Vehicles with standard tires:
• Stop your vehicle in a safe place as soon as possible. Adjust the tire inflation pressure immediately.
• If the tire pressure warning light comes on even after tire inflation pressure adjustment, it is probable that you have a flat tire. Check the tires. If the tire is
flat, change to the spare tire and have the flat tire repaired by the nearest
Lexus dealer.
• Avoid abrupt maneuvering and braking. If the vehicle tires deteriorate, you
could lose control of the steering wheel or the brakes.
■If a blowout or sudden air leakage should occur
The tire pressure warning system may not activate immediately.

5
When trouble arises
445
5-2. Steps to take in an emergency
Have the vehicle inspected by your Lexus dealer immediately.A buzzer sounds and a warning message is shown on the multi-informa-
tion display. Failing to investigate the cause of the following warnings may
lead to the system operating abnormally and possibly cause an accident.
Have the vehicle inspected by your Lexus dealer immediately.
Wa r n i n g m e s s a g eDetails
Malfunction in the automatic headlight leveling sys-
tem.
Malfunction in the rear lights system.
Malfunction in the tire pressure warning system.
The tire pressure warning light will blink for 1 minute
and then stay on.
(Flashing)
Malfunction in the steering lock system.

5
When trouble arises
447
5-2. Steps to take in an emergency
■If the tire pressure warning system is inoperative
The system will be disabled in the following conditions:
(When the condition becomes normal, the system will work properly.)
●If tires not equipped with tire pressure warning valves and transmitters are used.
●If the ID code on the tire pressure warning valves and transmitters is not regis-
tered in the tire pressure warning computer.
●If the tire inflation pressure is more than 73 psi (500 kPa, 5.1 kgf/cm2 or bar).
The system may be disabled in the following conditions:
(When the condition becomes normal, the system will work properly.)
●If electronic devices or facilities using similar radio wave frequencies are nearby.
●If a radio set at similar frequencies is in use in the vehicle.
●If a window tint that affects the radio wave signals is installed.
●If the tire pressure warning select switch is set to a different tire setting.
●If there is a lot of snow or ice on the vehicle, in particular around the wheels or
wheel housings.
●If non-genuine Lexus wheels are used.
●If tire chains are used.
■If the tire pressure warning light comes on after blinking for 1 minute frequently
If the tire pressure warning light comes on after blinking for 1 minute frequently
when the power switch is turned to “IG-ON” mode, have it checked by your Lexus
dealer.
NOTICE
■Precaution when insta lling a different tire
When a tire of a different specification or maker is installed, the tire pressure warn-
ing system may not operate properly.