
4657-3. Do-it-yourself maintenance
7
Maintenance and care
IS300h_EE(OM53C61E)
■Effects of incorrect tire inflation pressure
Driving with incorrect tire inflation pressure may result in the following:
●Reduced fuel economy
●Reduced driving comfort and poor handling
●Reduced tire life due to wear
●Reduced safety
●Damage to the drivetrain
If a tire needs frequent inflating, have it checked by any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
■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
1.5 km or 1 mile, you will get an accurate cold tire inflation pressure reading.
●Always use a tire pressure gauge.
It is difficult to judge if a tire is properly inflated based only on its appearance.
●It is normal for the tire inflation pressure to be higher after driving as heat is generated
in the tire. Do not reduce tire inflation pressure after driving.
●Passengers and luggage weight should be placed so that the vehicle is balanced.
Tire inflation pressure
Make sure to maintain proper tire inflation pressure. Tire inflation pressure
should be checked at least once per month. However, Lexus recommends
that tire inflation pressure be checked once every two weeks. (→P. 568)
IS300h_EE_OM53C61E.book 465 ページ 2014年5月20日 火曜日 午後5時40分

4667-3. Do-it-yourself maintenance
IS300h_EE(OM53C61E)
CAUTION
■Proper inflation is critical to save tire performance
Keep your tires properly inflated.
If the tires are not properly inflated, the following conditions may occur which could
lead to an accident resulting in death or serious injury:
●Excessive wear
●Uneven wear
●Poor handling
●Possibility of blowouts resulting from overheated tires
●Air leaking from between tire and wheel
●Wheel deformation and/or tire damage
●Greater possibility of tire damage while driving (due to road hazards, expansion
joints, sharp edges in the road, etc.)
NOTICE
■When inspecting and adjusting tire inflation pressure
Be sure to put the tire valve caps back on.
If the valve caps are not installed, dirt or moisture may get into the valve and cause air
leakage, which could result in a flat tire.
IS300h_EE_OM53C61E.book 466 ページ 2014年5月20日 火曜日 午後5時40分

4677-3. Do-it-yourself maintenance
7
Maintenance and care
IS300h_EE(OM53C61E)
When replacing wheels, care should be taken to ensure that they are equivalent
to those removed in load capacity, diameter, rim width and inset
*.
Replacement wheels are available at any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
*: Conventionally referred to as “offset”.
Lexus does not recommend using the following:
●Wheels of different sizes or types
●Used wheels
●Bent wheels that have been straightened
●Use only Lexus wheel nuts and wrenches designed for use with your alumi-
num wheels.
●When rotating, repairing or changing your tires, check that the wheel nuts are
still tight after driving 1600 km (1000 miles).
●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.
■When replacing wheels
The wheels of your vehicle are equipped with tire pressure warning valves and transmit-
ters that allow the tire pressure warning system to provide advance warning in the event
of a loss in tire inflation pressure. Whenever wheels are replaced, tire pressure warning
valves and transmitters must be installed. (→P. 4 5 1 )
Wheels
If a wheel is bent, cracked or heavily corroded, it should be replaced. Other-
wise, the tire may separate from the wheel or cause a loss of handling control.
Wheel selection
Aluminum wheel precautions
IS300h_EE_OM53C61E.book 467 ページ 2014年5月20日 火曜日 午後5時40分

4687-3. Do-it-yourself maintenance
IS300h_EE(OM53C61E)
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 a 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 any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional or other qualified ser-
vice shop. In addition, make sure to purchase your tire pressure warning valves and
transmitters at any authorized Lexus dealer or repairer, or another duly qualified and
equipped professional.
●Ensure that only genuine Lexus wheels are used on your vehicle.
Tire pressure warning valves and transmitters may not work properly with non-genu-
ine wheels.
IS300h_EE_OM53C61E.book 468 ページ 2014年5月20日 火曜日 午後5時40分

493
8When trouble arises
IS300h_EE(OM53C61E)
8-1. Essential information
Emergency flashers................... 494
If your vehicle has to
be stopped in an
emergency ................................. 4958-2. Steps to take in an
emergency
If your vehicle needs to
be towed ..................................... 496
If you think something is
wrong ...........................................502
If a warning light turns
on or a warning buzzer
sounds..........................................503
If a warning message is
displayed.....................................509
If you have a flat tire
(vehicles without
run-flat tires).............................. 526
If you have a flat tire
(vehicles with
run-flat tires)..............................540
If the hybrid system will
not start ........................................ 541
If the shift lever cannot
be shifted from P ..................... 543
If the electronic key does
not operate properly ............. 544
If the 12-volt battery is
discharged ................................. 547
If your vehicle overheats ......... 552
If the vehicle becomes
stuck ............................................. 556
IS300h_EE_OM53C61E.book 493 ページ 2014年5月20日 火曜日 午後5時40分

5008-2. Steps to take in an emergency
IS300h_EE(OM53C61E)
■While towing
If the hybrid system is off, 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 5 9 )
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 a 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 power 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,
an accident may occur due to a change in
direction of the vehicle or electricity generated
by the operation of the motor may cause a fire
to occur depending on the nature of the dam-
age or malfunction.
IS300h_EE_OM53C61E.book 500 ページ 2014年5月20日 火曜日 午後5時40分

5028-2. Steps to take in an emergency
IS300h_EE(OM53C61E)
●Fluid leaks under the vehicle.
(Water dripping from the air conditioning after use is normal.)
●Flat-looking tires or uneven tire wear
●Engine coolant temperature gauge needle continually points higher than nor-
mal.
●Changes in exhaust sound
●Excessive tire squeal when cornering
●Strange noises related to the suspension system
●Pinging or other noises related to the hybrid system
●Engine missing, stumbling or running roughly
●Appreciable loss of power
●Vehicle pulls heavily to one side when braking
●Vehicle pulls heavily to one side when driving on a level road
●Loss of brake effectiveness, spongy feeling, pedal almost touches the floor
If you think something is wrong
If you notice any of the following symptoms, your vehicle probably needs
adjustment or repair. Contact any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional as soon as possible.
Visible s ymp toms
Audible symptoms
Operational symptoms
IS300h_EE_OM53C61E.book 502 ページ 2014年5月20日 火曜日 午後5時40分

5078-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53C61E)
■If the tire pressure warning light frequently comes on after blinking for 1 minute
If the tire pressure warning light frequently comes on after blinking for 1 minute when the
power switch is turned to 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
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 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.
XVehicles with run-flat tires
●Decelerate to the lowest appropriate speed as soon as possible. Do not drive over 60
km/h (37 mph).
●Check and 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. Have the tire replaced by the nearest
authorized Lexus dealer or repairer, or another duly qualified and equipped profes-
sional.
●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.
IS300h_EE_OM53C61E.book 507 ページ 2014年5月20日 火曜日 午後5時40分