Page 796 of 1014

7726-3. Do-it-yourself maintenance
GS450h_300h_OM_OM30D53E_(EE)
Tire inflation pressure
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 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.
The appearance of the tire can be misleading. In addition, tire inflation pres-
sure that is even just a few pounds off can affect ride quality and handling.
Do not reduce tire inflation pressure after driving. It is normal for tire infla-
tion 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.
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. 936)
Page 797 of 1014
773 6-3. Do-it-yourself maintenance
6
Maintenance and care
GS450h_300h_OM_OM30D53E_(EE)
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 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 799 of 1014

775
6 6-3. Do-it-yourself maintenance
Maintenance and care
GS450h_300h_OM_OM30D53E_(EE)
Use only Lexus wheel nuts and wrenches designed for use with
your aluminum 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 transmitters 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. 756)
Aluminum wheel precautions
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 tube-
less tire. Doing so may result in an accident, causing death or serious
injury.
Do not install steel wheels.
The wheel contact surface could be damaged, and the wheel could come
off while driving, which could lead to an accident resulting in death or
serious injury. (except for vehicles with a steel spare wheel)
Use of defective wheels prohibited
Do not use cracked or deformed wheels.
Doing so could cause the tire to leak air during driving, possibly causing an
accident.
Page 845 of 1014

819
7When trouble arises
GS450h_300h_OM_OM30D53E_(EE)7-1. Essential information
Emergency flashers ........... 820
If your vehicle
has to be stopped
in an emergency .............. 8217-2. Steps to take in an emergency
If your vehicle needs
to be towed ..................... 822
If you think something
is wrong .......................... 829
If a warning light turns on
or a warning buzzer
sounds ............................. 830
If a warning message
is displayed ..................... 838
If you have a flat tire (vehicles
with a spare tire) ............. 870
If you have a flat tire (vehicles
without a spare tire) ........ 884
If the hybrid system
will not start .................... 902
If the shift lever cannot be
shifted from P ................. 904
If the parking brake
cannot be released........... 905
If the electronic key does not
operate properly .............. 908
If the 12-volt battery
is discharged ....................911
If your vehicle overheats .. 915
If the vehicle
becomes stuck................. 923
Page 856 of 1014

829
7 7-2. Steps to take in an emergency
When trouble arises
GS450h_300h_OM_OM30D53E_(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 normal.
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 proba-
bly needs adjustment or repair. Contact any authorized Lexus
dealer or repairer, or another duly qualified and equipped profes-
sional as soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms
Page 862 of 1014

8357-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30D53E_(EE)
*1: Open door warning buzzer:
P. 8 4 8
*2: 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.
(If equipped)
Tire pressure warning light
When the light comes on:
Low tire inflation pressure
such as
• Natural causes (P.
836)
• Flat tire (P. 871, 885)
Adjust the tire inflation pres-
sure 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 sys-
tem checked by any autho-
rized Lexus dealer or
repairer, or another duly
qualified and equipped
professional.
When the light comes on
after blinking for 1 minute:
Malfunction in the tire pres-
sure warning systemHave the system checked by
any authorized Lexus dealer
or repairer, or another duly
qualified and equipped pro-
fessional.
Wa r n i n g
lightWarning light/DetailsCorrection procedure
Page 863 of 1014

8367-2. Steps to take in an emergency
GS450h_300h_OM_OM30D53E_(EE)
Front passenger detection sensor, seat belt reminder and warning buzzer
If luggage is placed on the front passenger seat, the front passenger detec-
tion sensor may cause the warning light to flash and the warning buzzer to
sound even if a passenger is not sitting in the seat.
If a cushion is placed on the seat, the sensor may not detect a passenger, and
the warning 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 com-
pletely 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 insufficient or the voltage tempo-
rarily 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
Carry out the following procedure after the tire temperature has lowered suf-
ficiently.
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 inflation pressure is at the specified 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.
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).
Page 864 of 1014
8377-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30D53E_(EE)
When a tire is replaced with a spare tire
The compact spare tire is not equipped with a tire pressure warning valve and
transmitter. 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. 7 6 0
If the tire pressure warning light frequently comes on after blinking for 1 min-
ute
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.