
445
6
6-3. Do-it-yourself maintenance
Maintenance and care
GS450h_300h_OM_OM30F00E_(EE)
Tire inflation pressure
■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 drive train
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 prop erly 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 pl aced so that the vehicle is balanced.
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. 5 7 5 )
WA R N I N G
■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.)

4466-3. Do-it-yourself maintenance
GS450h_300h_OM_OM30F00E_(EE)
NOTICE
■When inspecting and adjusting tire inflation pressure
Be sure to put the tire valve caps back on.
If a valve cap is not installed, dirt or moisture may get into the valve and cause an air
leak, resulting in decrease d tire inflation pressure.

447
6
6-3. Do-it-yourself maintenance
Maintenance and care
GS450h_300h_OM_OM30F00E_(EE)
Wheels
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
●Steel wheels (except for vehicles with steel spare wheel)
●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 (vehicles with the tire pressure warning system)
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. 434)
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

467
7When trouble arises
GS450h_300h_OM_OM30F00E_(EE)
7-1. Essential informationEmergency flashers...................468
If your vehicle has to be stopped in an
emergency ................................. 469 7-2. Steps to take in an emergency
If your vehicle needs to be towed................................ 470
If you think something is wrong........................................475
If a warning light turns on or a warning buzzer
sounds........................................... 476
If a warning message is displayed ................................ 482
If you have a flat tire (vehicles with spare tire)............................517
If you have a flat tire (vehicles without spare tire)................... 528
If the hybrid system will not start ............................... 543
If the shift lever cannot be shifted from P............................ 545
If the parking brake cannot be released................. 546
If the electronic key does not operate properly .....................548
If the 12-volt battery is discharged .................................. 551
If your vehicle overheats ......... 556
If the vehicle becomes stuck ............................................. 563

475
7
7-2. Steps to take in an emergency
When trouble arises
GS450h_300h_OM_OM30F00E_(EE)
If you think something is wrong
●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 notice any of the following symptoms, your vehicle probably needs
adjustment or repair. Contact any authorized Lexus dealer or repairer, or
another duly qualified an
d equipped professional as soon as possible.
Visible s ymp toms
Audible symptoms
Operational symptoms

4797-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30F00E_(EE)
*: Driver’s and front passenger’s seat belt buzzer:The driver’s and front passenger’s seat belt buzzer sounds to alert the driver and front
passenger that his or her seat belt is not fastened. The buzzer sounds intermittently for
30 seconds after the vehicle reaches a speed of 20 km/h (12 mph). Then, if the seat
belt is still unfastened , the buzzer will sound in a different tone for 90 more seconds.
■Front passenger detection sensor, seat belt reminder and warning buzzer
●If luggage is placed on the front passenge r seat, the front passenger detection sensor
may cause the warning light to flash and the warning buzzer to sound even if a passen-
ger is not sitting in the seat.
●If a cushion is placed on the seat, the sensor may not detect a passenger, and the warn-
ing light may not operate properly.
■If the malfunction indicator lamp comes on while driving
The malfunction indicator lamp will come on if the fuel tank becomes completely empty.
If the fuel tank is empty, refuel the vehicle immediately. The malfunction indicator lamp
will go off after several trips.
If the malfunction indicator lamp does not go off, contact any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional as soon as possible.
■Electric power steering system warning light (warning buzzer)
When the 12-volt battery charge becomes insu fficient or the voltage temporarily drops,
the electric power steering system warning light may come on and the warning buzzer
may sound.
■When the tire pressure warning light comes on (if equipped)
Carry out the following procedure after the tire temperature has lowered sufficiently.
●Check the tire inflation pressure and adjust to the appropriate level.
●If the warning light does not go out even after several minutes, check that the tire infla-
tion pressure is at the specifie d level and carry out initialization.
The warning light may come on again if the above operations are conducted without first
allowing the tire temperature to lower sufficiently.
(If equipped)
Tire pressure warning light When the light comes on:
Low tire inflation pressure such as
• Natural causes ( →P. 4 8 0 )
• Flat tire ( →P. 5 1 7 , 5 2 8 )
→ Adjust the tire inflation pre ssure to the specified level.
The light will turn off after a few minutes. In case the light does
not turn off even if the tire inflation pressure is adjusted, have the
system checked by any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
When the light comes on af ter blinking for 1 minute:
Malfunction in the tire pressure warning system
→ Have the system checked by any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
Warning lightWarning light/Details/Actions

4807-2. Steps to take in an emergency
GS450h_300h_OM_OM30F00E_(EE)
■The tire pressure warning light may come on due to natural causes
The tire pressure warning light may come on due to natural causes such as natural air
leaks and tire inflation pressure changes caused by temperature. In this case, adjusting
the tire inflation pressure will turn off the warning light (after a few minutes).
■When a tire is replaced with a spare tire
The compact spare tire is not equipped with a tire pressure warning valve and transmit-
ter. If a tire goes flat, the tire pressure warning light will not turn off even though the flat
tire has been replaced with the spare tire.
■Conditions that the tire pressure warning system may not function properly
→P. 4 3 6
■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 because of noisy place or an audio sound.
WA R N I N G
■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 us ual 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.
●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 any 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.
■If a blowout or sudden air leakage should occur
The tire pressure warning system may not activate immediately.

5047-2. Steps to take in an emergency
GS450h_300h_OM_OM30F00E_(EE)
(If equipped)
Indicates that the tire inflation pressure is low
→Check the tire inflation pressure, and adjust to the
appropriate level.
(If equipped)
Indicates a malfunction in th e tire pressure warning sys-
tem
→ Stop the vehicle in a safe place and turn the power
switch off then on again. If the tire pressure warning
indicator flashes for 1 minute then illuminates, there
is a malfunction in the system. Have the vehicle
inspected by any authorized Lexus dealer or
repairer, or another duly qualified and equipped
professional.
(If equipped)
Indicates that the tire position information cannot be rec-
ognized
→Drive for a short while an d check if the display
updates.
If the radio wave conditions improve, the display
may return to normal. If the tire pressure is still not
displayed after driving for several minutes, stop the
vehicle in a safe place, turn the power switch off
then on again, and start driving. If the tire pressure is
still not displayed even after repeating this process
several times, have the vehicle inspected by any
authorized
Lexus dealer or repairer, or another duly qualified
and equipped professional.
Wa r n i n g m e s s a g eDetails/Actions