Page 428 of 588

4287-3. Do-it-yourself maintenance
IS250_EE(OM53C51E)
Your vehicle is equipped with a tire pressure warning system that uses tire pres-
sure warning valves and transmitters to detect low tire inflation pressure before
serious problems arise.
If the tire pressure drops below a predetermined level, the driver is warned by a
warning light. (→P. 4 7 8 )
◆Installing tire pressure warning valves and transmitters
When replacing tires or wheels, tire pressure warning valves and transmitters
must also be installed.
When new tire pressure warning valves and transmitters are installed, new ID
codes must be registered in the tire pressure warning computer and the tire
pressure warning system must be initialized. Have tire pressure warning valve
and transmitter ID codes registered by any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional. (→P. 4 2 9 )
◆Initializing the tire pressure warning system
■The tire pressure warning system must be initialized in the following circum-
stances:
●When rotating the tires.
●When the tire inflation pressure is changed such as when changing travel-
ing speed or load weight.
●When changing the tire size.
When the tire pressure warning system is initialized, the current tire inflation
pressure is set as the benchmark pressure.
Tire pressure warning system (if equipped)
Page 431 of 588

4317-3. Do-it-yourself maintenance
7
Maintenance and care
IS250_EE(OM53C51E)
■Situations in which the tire pressure warning system may not operate properly (vehi-
cles with a tire pressure warning system)
●In the following cases, the tire pressure warning system may not operate properly.
• If non-genuine Lexus wheels are used.
• A tire has been replaced with a tire that is not an OE (Original Equipment) tire.
• A tire has been replaced with a tire that is not of the specified size.
• Tire chains etc. are equipped.
• Lock nuts are equipped.
• An auxiliary-supported run-flat tire is equipped.
• If a window tint that affects the radio wave signals is installed.
• If there is a lot of snow or ice on the vehicle, particularly around the wheels or wheel
housings.
• If the tire inflation pressure is extremely higher than the specified level.
• 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 registered
in the tire pressure warning computer.
●Performance may be affected in the following situations.
• Near a TV tower, electric power plant, gas station, radio station, large display, air-
port or other facility that generates strong radio waves or electrical noise
• When carrying a portable radio, cellular phone, cordless phone or other wireless
communication device
●When the vehicle is parked, the time taken for the warning to start or go off could be
extended.
●When tire inflation pressure declines rapidly for example when a tire has burst, the
warning may not function.
■The initialization operation (vehicles with a tire pressure warning system)
●Make sure to carry out initialization after adjusting the tire inflation pressure.
Also, make sure the tires are cold before carrying out initialization or tire inflation pres-
sure adjustment.
●If you have accidentally turned the engine switch off during initialization, it is not neces-
sary to press the reset switch again as initialization will restart automatically when the
engine switch has been turned to IGNITION ON mode for the next time.
●If you accidentally press the reset switch when initialization is not necessary, adjust the
tire inflation pressure to the specified level when the tires are cold, and conduct initial-
ization again.
■Warning performance of the tire pressure warning system (if equipped)
The warning of the tire pressure warning system will change in accordance with the con-
ditions under which it was initialized. For this reason, the system may give a warning even
if the tire pressure does not reach a low enough level, or if the pressure is higher than the
pressure that was adjusted to when the system was initialized.
Page 472 of 588

4728-2. Steps to take in an emergency
IS250_EE(OM53C51E)
■While towing
If the engine is not running, the power assist for the brakes and steering will not function,
making steering and braking more difficult.
■Wheel nut wrench
Wheel nut wrench is installed in luggage compartment. (→P. 4 9 7 , 5 0 8 )
CAUTION
Observe the following precautions.
Failure to do so may result in death or serious injury.
■When towing the vehicle
■While towing
●When towing using cables or chains, avoid sudden starts, etc. which place excessive
stress on the towing eyelet, cables or chains.
The towing eyelet, cables or chains may become damaged, broken debris may hit
people and cause serious damage.
●Do not turn the engine switch off.
There is a possibility that the steering wheel is locked and cannot be operated.
■Installing towing eyelet to the vehicle
Make sure that towing eyelet is installed securely.
If not securely installed, towing eyelet may come loose during towing.
Be sure to transport the vehicle with all four
wheels raised off the ground. If the vehicle is
towed with the tires contacting the ground, the
drivetrain and related parts may be damaged
or an accident may occur due to a change in
direction of the vehicle.
Page 480 of 588

4808-2. Steps to take in an emergency
IS250_EE(OM53C51E)
■If the tire pressure warning light frequently comes on after blinking for 1 minute (if
equipped)
If the tire pressure warning light frequently comes on after blinking for 1 minute when the
engine switch is turned to IGNITION ON mode, have it checked by any authorized
Lexus dealer or repairer, or another duly qualified and equipped professional.
■Warning buzzer
In some cases, the buzzer may not be heard due to being in a noisy location or audio
sound.
CAUTION
■If both the ABS and the brake system warning lights remain on
Stop your vehicle in a safe place immediately and contact any authorized Lexus dealer
or repairer, or another duly qualified and equipped professional. The vehicle will
become extremely unstable during braking, and the ABS system may fail, which could
cause an accident resulting in death or serious injury.
■When the electric power steering system warning light comes on
The steering wheel may become extremely heavy.
If the steering wheel becomes heavier than usual when operating, hold firmly and oper-
ate using more force than usual.
■If the tire pressure warning light comes on (if equipped)
Be sure to observe the following precautions. Failure to do so could cause a loss of
vehicle control and result in death or serious injury.
XVehicles with a compact spare tire
●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 adjust-
ment, it is probable that you have a flat tire. Check the tires. If a tire is flat, change it
with the spare tire and have the flat tire repaired by the nearest authorized Lexus
dealer or repairer, or another duly qualified and equipped professional.
●Avoid abrupt maneuvering and braking. If the vehicle tires deteriorate, you could lose
control of the steering wheel or the brakes.
XVehicles with an emergency tire puncture repair kit
●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 adjust-
ment, it is probable that you have a flat tire. Check the tires. If a tire is flat, repair the
flat tire by using emergency tire puncture repair kit.
●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.