warning LEXUS RX450h 2021 Owners Manual

3756-3. Do-it-yourself maintenance
6
Maintenance and care
■Checking fluid level
The brake fluid level should be
between the “MAX” and “MIN” lines
on the tank.
■Adding fluid
Make sure to check the fluid type and
prepare the necessary item.
 Fluid type
FMVSS No.116 DOT 3 or SAE J1703
brake fluid
Item
Clean funnel
■Brake fluid can absorb moisture from
the air
Excess moisture in the brake fluid can cause
a dangerous loss of braking efficiency. Use
only newly opened brake fluid.
If any washer does not work or the
warning message appears on the
multi-information display, the washer
tank may be empty. Add washer fluid.
WARNING
■When the hybrid system is hot
Do not touch the radiator or condenser
as they may be hot and cause serious
injuries, such as burns.
Checking and adding the brake
fluid
WARNING
■When filling the reservoir
Take care as brake fluid can harm your
hands and eyes and damage painted sur-
faces.
If fluid gets on your hands or in your eyes,
flush the affected area with clean water
immediately.
If you still experience discomfort, see a
doctor.
NOTICE
■If the fluid level is low or high
It is normal for the brake fluid level to go
down slightly as the brake pads wear out
or when the fluid leve l in the accumulator
is high.
If the reservoir needs frequent refilling,
there may be a serious problem.
Washer fluid
WARNING
■When adding washer fluid
Do not add washer fluid when the hybrid
system is hot or operating as washer fluid
contains alcohol and may catch fire if
spilled on the engine, etc.

3786-3. Do-it-yourself maintenance
WARNING
■Chemicals in the 12-volt battery
The 12-volt battery contains poisonous
and corrosive sulfuric acid and may pro-
duce hydrogen gas which is flammable
and explosive. To reduce the risk of death
or serious injury, take the following pre-
cautions while working on or near the
12-volt battery:
●Do not cause sparks by touching the
12-volt battery terminals with tools.
●Do not smoke or light a match near the
12-volt battery.
●Avoid contact with eyes, skin and
clothes.
●Never inhale or swallow electrolyte.
●Wear protective safety glasses when
working near the 12-volt battery.
●Keep children away from the 12-volt
battery.
■Where to safely charge the 12-volt
battery
Always charge the 12-volt battery in an
open area. Do not charge the 12-volt bat-
tery in a garage or closed room where
there is insufficient ventilation.
■How to recharge the 12-volt battery
Only perform a slow charge (5 A or
less). The 12-volt battery may explode if
charged at a quicker rate.
■Emergency measures regarding
electrolyte
●If electrolyte gets in your eyes
Flush your eyes with clean water for at
least 15 minutes and get immediate
medical attention. If possible, continue
to apply water with a sponge or cloth
while traveling to the nearest medical
facility.
●If electrolyte gets on your skin
Wash the affected area thoroughly. If
you feel pain or burning, get medical
attention immediately.
●If electrolyte gets on your clothes
It can soak through clothing on to your
skin. Immediately take off the clothing
and follow the procedure above if nec-
essary.
●If you accidentally swallow electrolyte
Drink a large quantity of water or milk.
Get emergency medical attention
immediately.
■When replacing the 12-volt battery
Use a 12-volt battery designed for this
vehicle. Failure to do so may cause gas
(hydrogen) to enter the passenger com-
partment, causing a fire or explosion.
For replacement of the 12-volt battery,
contact your Lexus dealer.
■When handling the 12-volt battery
 P.453
■When disconnecting the 12-volt bat-
tery (RX450h)
Do not disconnect the negative (-) termi-
nal on the body side as shown. The dis-
connected negative (-) terminal may
touch the positive (+) terminal, which
may cause a short and result in death or
serious injury.
NOTICE
■When recharging the 12-volt battery
Never recharge the 12-volt battery while
the hybrid system is operating. Also, be
sure all accessories are turned off.

3816-3. Do-it-yourself maintenance
6
Maintenance and care
inspected at your Lexus dealer.
■Maximum load of tire
Check that the maximum load of the
replacement tire is greater than 1/2 of the
Gross Axle Weight Ratings (GAWR) of
either the front axle or the rear axle, which-
ever is greater.
For the GAWR, see the Certification Label.
For the maximum load of the tire, see the
load limit at maximum cold tire inflation
pressure mentioned on the sidewall of the
tire. ( P.471)
■Tire types
●Summer tires
Summer tires are high-speed performance
tires best suited to highway driving under
dry conditions. Since summer tires do not
have the same traction performance as
snow tires, summer tires are inadequate for
driving on snow-covered or icy roads. For
driving on snow-covered roads or icy
roads, the use of snow tires is recom-
mended. When installing snow tires, be
sure to replace all four tires.
●All season tires
All season tires are designed to provide
better traction in snow and to be adequate
for driving in most winter conditions as well
as for use year-round. All season tires,
however, do not have adequate traction
performance compared with snow tires in
heavy or loose snow. Also, all season tires
fall short in acceleration and handling per-
formance compared with summer tires in
highway driving.
●Snow tires
For driving on snow-covered roads or icy roads, we recommend using snow tires. If
you need snow tires, select tires of the
same size, construction and load capacity
as the originally instal
led tires. Since your
vehicle has radial tires as original equip-
ment, make sure your snow tires also have
radial construction. Do not install studded
tires without first checking local regula-
tions for possible restrictions. Snow tires
should be installe d on all wheels. (P.291)
■If the tread on snow tires wears down
below 0.16 in. (4 mm)
The effectiveness of the tires as snow tires is
lost.
WARNING
■When inspecting or replacing tires
Observe the following precautions to
prevent accidents.
Failure to do so may cause damage to
parts of the drive train as well as danger-
ous handling characteristics, which may
lead to an accident resulting in death or
serious injury.
●Do not mix tires of different makes,
models or tread patterns.
Also, do not mix tires of remarkably
different treadwear.
●Do not use tire sizes other than those
recommended by Lexus.
●Do not mix differently constructed
tires (radial, bias-belted or bias-ply
tires).
●Do not mix summer, all season and
snow tires.
●Do not use tires that have been used
on another vehicle.
Do not use tires if you do not know
how they were used previously.
●Do not tow if your vehicle has a com-
pact spare tire installed.

3826-3. Do-it-yourself maintenance
Rotate the tires in the order shown.
To equalize tire wear and extend tire life,
Lexus recommends that tire rotation is car-
ried out at the same interval as tire inspec-
tion.
Do not fail to initialize the tire pressure
warning system after tire rotation.
Your vehicle is equipped with a tire
pressure warning system that uses tire
pressure warning valves and transmit-
ters to detect low tire inflation pressure
before serious problems arise.
The tire pressure detected by the tire pressure warning system can be
displayed on the multi-information
display. (
P.88)
The illustration used is intended as an
example, and may differ from the image
that is actually displayed on the multi-infor-
mation display.
 If the tire pressure drops below a
predetermined level, the driver is
warned by a screen display and a
warning light. ( P.422)
The illustration used is intended as an
example, and may differ from the image
that is actually displayed on the multi-infor-
mation display.
■Routine tire inflation pressure checks
The tire pressure warning system does not
replace routine tire inflation pressure
checks. Make sure to check tire inflation
pressure as part of your routine of daily
vehicle checks.
NOTICE
■Driving on rough roads
Take particular care when driving on
roads with loose surfaces or potholes.
These conditions may cause losses in tire
inflation pressure, reducing the cushion-
ing ability of the tires. In addition, driving
on rough roads may cause damage to
the tires themselves, as well as the vehi-
cle’s wheels and body.
■If tire inflation pres sure of each tire
becomes low while driving
Do not continue driving, or your tires
and/or wheels may be ruined.
Tire rotation
Tire pressure warning system

3836-3. Do-it-yourself maintenance
6
Maintenance and care
■Situations in which the tire pressure
warning system may not operate prop-
erly
●In the following cases, the tire pressure
warning system may not operate prop-
erly.
• 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.
• If a window tint that affects the radio wave signals is installed.
• If there is a lot of snow or ice on the vehi- cle, particularly around the wheels or
wheel housings.
• If the tire inflation pressure is extremely higher than the specified level.
• If wheel without the tire pressure warning
valve and transmitter is used.
• If the ID code on the tire pressure warn- ing valves and transmitters is not regis-
tered in the tire pressure warning
computer.
●Performance may be affected in the fol-
lowing situations.
• Near a TV tower, electric power plant, gas station, radio stat
ion, large display,
airport or other fac ility that generates
strong radio waves or electrical noise
• When carrying a portable radio, cellular phone, cordless phone or other wireless
communication device
If tire position information is not correctly
displayed due to the radio wave conditions,
the display may be corrected by driving and
changing the radio wave conditions.
●When the vehicle is parked, the time
taken for the warning to start or go off
could be extended.
●When tire inflation pr essure declines rap-
idly for example when a tire has burst, the
warning may not function.
■Warning performance of the tire pres-
sure warning system
The warning of the tire pressure warning
system will change in accordance with the
conditions 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.
■Tire pressure warning system certification
Except for vehicles sold in Canada

3846-3. Do-it-yourself maintenance
For vehicles sold in Canada
When replacing tires or wheels, tire
pressure warning valves and transmit-
ters 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 warn-
ing valve and transmitter ID codes reg-
istered by your Lexus dealer.
Installing tire pressure warning
valves and transmitters

3856-3. Do-it-yourself maintenance
6
Maintenance and care
( P.387)
■Replacing tires and wheels
If the ID code of the tire pressure warning
valve and transmitter is not registered, the
tire pressure warning system will not work
properly. After driving for about 20 min-
utes, the tire pressure warning light blinks
for 1 minute and stays on to indicate a sys-
tem malfunction.
■The tire pressure warning system
must be initialized in the following
circumstances:
 When the tire inflation pressure is
changed such as when changing
traveling speed.
 When the tire inflation pressure is
changed such as when the tire size
is changed.
 When rotating the tires.
When the tire pressure warning system
is initialized, the current tire inflation
pressure is set as the benchmark pres-
sure.
■How to initialize the tire pressure
warning system
1 Park the vehicle in a safe place and
turn the power switch off.
Initialization cannot be performed while
the vehicle is moving.
2 Adjust the tire inflation pressure to
the specified cold tire inflation pres-
sure level.
Make sure to adjust the tire pressure to the
specified cold tire infl ation pressure level.
The tire pressure warning system will oper-
ate based on this pressure level.
3 Turn the power switch to ON
mode.
4 Select on the multi-information
display.
5 Press or of the meter con-
trol switch, select the “Vehicle Set-
NOTICE
■Repairing or replacing tires, wheels,
tire pressure warning valves, trans-
mitters and tire valve caps
●When removing or fitting the wheels,
tires or the tire pressure warning
valves and transmitters, contact your
Lexus dealer as the tire pressure warn-
ing valves and transmitters may be
damaged if not handled correctly.
●Make sure to install the tire valve caps.
If the tire valve caps are not installed,
water could enter the tire pressure
warning valves and the tire pressure
warning valves could be bound.
●When replacing tire valve caps, do not
use tire valve caps other than those
specified. The cap may become stuck.
■To avoid damage to the tire pressure
warning valves and transmitters
When a tire is repaired with liquid seal-
ants, the tire pressu re warning valve and
transmitter may not operate properly. If a
liquid sealant is used , contact your Lexus
dealer or other qualified service shop as
soon as possible. Make sure to replace
the tire pressure warning valve and trans-
mitter when replacing the tire. ( P.384)
Initializing the tire pressure
warning system

3866-3. Do-it-yourself maintenance
tings” screen and then press the .
6 Press or of the meter con-
trol switch, select the “TPMS”
screen and then press and hold the
until the tire pressure warn-
ing light blinks slowly 3 times.
“- -” will be displayed for inflation pressure
of each tire on the multi-information dis-
play while the tire pr essure warning system
determines the position of each tire.
7 Drive the vehicle at approximately
25 mph (40 km/h) or more for
approximately 10 to 30 minutes
until the inflation pressure of each
tire is displayed on the multi-infor-
mation display.
When position of each tire is determined,
the inflation pressure of each tire will be
displayed on the multi-information display.
If tire inflation pr essure becomes low
before the inflation pr essure is displayed,
the tire pressure warning light will come
on.
Depending on the vehicle and driving con-
ditions, initialization may take up to
approximately 1 hour to complete.
■Initializing the tire pressure warning sys-
tem
Initialize the system with the tire inflation
pressure adjusted to the specified level.
■If you press the tire pressure warning
reset switch accidentally
If initialization is perf ormed, adjust the tire
inflation pressure to the specified level and
initialize the tire pressure warning system
again.
■Initialization procedure
●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
pressure adjustment.
●If you have accidentally turned the power
switch off during initialization, it is not
necessary to press the reset switch again
as initialization will restart automatically
when the power switch has been turned
to 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
initialization again.
●While the position of each tire is being
determined and the inflation pressures
are not being displayed on the
multi-information display, if the inflation
pressure of a tire drops, the tire pressure
warning light will come on.
■When initialization of the tire pressure
warning system has failed
Initialization may take longer to complete if
the vehicle is driven on an unpaved road.
When performing initia lization, drive on a
paved road if possible. Depending on the
driving environment and condition of the
tires, initialization will be completed in
approximately 10 to 30 minutes. If initializa-
tion is not complete after driving approxi-
mately 10 to 30 minutes, continue driving
for a while.
If the inflation pressure of each tire is not
displayed after driving for approximately 1
hour, perform the following procedure.
●Park the vehicle in a safe place for
approximately 20 minutes. Then drive
straight (with occasional left and right
turns) at approximately 25 mph (40
km/h) or more for approximately 10 to
30 minutes.

3876-3. Do-it-yourself maintenance
6
Maintenance and care
However, in the following situations, the tire
inflation pressure will not be recorded and
the system will not operate properly. Per-
form initialization again.
●When operating the tire pressure warn-
ing reset switch, the tire pressure warning
light does not blink 3 times.
●After performing init ialization, the tire
pressure warning light blinks for 1 minute
then stays on while driving.
If the inflation pressure of each tire is still not
displayed, have the vehicle inspected by
your Lexus dealer.
The tire pressure warning valve and
transmitter is equipped with a unique
ID code. When replacing a tire pres-
sure warning valve and transmitter, it is
necessary to register the ID code.
Have the ID code registered by your
Lexus dealer. The recommended cold tire inflation
pressure and tire size are displayed on
the tire and loading information label.
(
P.460)
Tire valve
Tire pressure gauge
WARNING
■When initializing the tire pressure
warning system
Do not initializing tire inflation pressure
without first adjusting the tire inflation
pressure to the spec ified level. Other-
wise, the tire pressure warning light may
not come on even if the tire inflation pres-
sure is low, or it may come on when the
tire inflation pressure is actually normal.
Registering ID codes
Tire inflation pressure
Checking the specified tire infla-
tion pressure
Inspection and adjustment pro-
cedure
A
B

3886-3. Do-it-yourself maintenance
1Remove the tire valve cap.
2 Press the tip of the tire pressure
gauge onto the tire valve.
3 Read the pressure using the gauge
gradations.
4 If the tire inflation pressure is not at
the recommended level, adjust the
pressure.
If you add too much air, press the
center of the valve to deflate.
5 After completing the tire inflation
pressure measurem ent and adjust-
ment, apply soapy water to the
valve and check for leakage.
6 Put the tire valve cap back on.
■Tire inflation pressure check interval
You should check tire inflation pressure
every two weeks, or at least once a month.
Do not forget to check the spare.
■Effects of incorrect tire inflation pres-
sure
Driving with incorrect ti re inflation pressure
may result in the following:
●Reduced fuel economy
●Reduced driving comfort and poor han-
dling
●Reduced tire life due to wear
●Reduced safety
●Damage to the drive train
If a tire needs frequent inflating, 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 or has not been driven for
more than 1 mile or 1.5 km, you will get an
accurate cold tire in flation pressure read- ing.
●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 ti
re inflation pressure
to be higher after driving as heat is gen-
erated in the tire. Do not reduce tire infla-
tion pressure after driving.
●Never exceed the vehicle capacity
weight.
Passengers and luggage weight should
be placed so that the vehicle is balanced.
WARNING
■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 dam-
age
●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 a valve cap is not installed, dirt or mois-
ture may get into the valve and cause an
air leak, resulting in decreased tire infla-
tion pressure.