
4816-3. Do-it-yourself maintenance
6
Maintenance and care
RX450h_U_OM0E013U
■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.
■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.
Brake fluid
Fluid typeFMVSS No.116 DOT 3 or SAE J1703 brake fluid
ItemsClean funnel
WARNING
■When filling the reservoir
Take care as brake fluid can harm your hands and eyes and damage painted surfaces.
If fluid gets on your hands or in your eyes, flush the affected area with clean water
immediately.
If you still experience di scomfort, 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 level in the accumulator is high.
If the reservoir needs frequent ref illing, there may be a serious problem.

4826-3. Do-it-yourself maintenance
RX450h_U_OM0E013U
If none of the washer do not work or the
“Windshield Washer Fluid Low”
appears on the multi-information dis-
play, the washer tank may be empty.
Add washer fluid.
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.
NOTICE
■Do not use any fluid other than washer fluid
Do not use soapy water or engine antifreeze instead of washer fluid.
Doing so may cause streaking on the vehicle’s painted surfaces.
■Diluting washer fluid
Dilute washer fluid with water as necessary.
Refer to the freezing temperatures listed on the label of the washer fluid bottle.

4846-3. Do-it-yourself maintenance
RX450h_U_OM0E013U
Make sure that the 12-volt battery terminals are not corroded and that there are
no loose connections, cracks, or loose clamps. Terminals
Hold-down clamp
Install the 12-volt battery cover with the
clips. Push up center position
Insert
Press
■Before recharging
When recharging, the 12-volt battery produces hydrogen gas which is flammable and
explosive. Therefore, observe the following precautions before recharging:
●If recharging with the 12-volt battery installed on the vehicle, be sure to disconnect the
ground cable.
●Make sure the power switch on the charge r is off when connecting and disconnecting
the charger cables to the 12-volt battery.
■After recharging/reconnecting the 12-volt battery
●The hybrid system may not start. Follow the procedure below to initialize the system.
Shift the shift lever to P.
Open and close any of the doors.
Restart the hybrid system.
●Unlocking the doors using the smart access system with push-button start may not be
possible immediately after reconnecting the 12-volt battery. If this happens, use the
wireless remote control or the mechan ical key to lock/unlock the doors.
●Start the hybrid system with the power sw itch in ACCESSORY mode. The hybrid sys-
tem may not start with the power switch turned off. However, the hybrid system will
operate normally from the second attempt.
Exterior
1
2
Installing the 12-volt battery cover
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2
3
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2
3

4856-3. Do-it-yourself maintenance
6
Maintenance and care
RX450h_U_OM0E013U
●The power switch mode is recorded by the vehicle. If the 12-volt battery is reconnected,
the vehicle will return the power switch mode to the status it was in before the 12-volt
battery was disconnected. Make sure to turn off the power before disconnect the 12-
volt battery. Take extra care when connec ting the 12-volt battery if the power switch
mode prior to discharge is unknown.
If the system will not start even after multip le attempts at all methods above, contact your
Lexus dealer.
WARNING
■Chemicals in the 12-volt battery
The 12-volt battery contains poisonous and corrosive sulfuric acid and may produce
hydrogen gas which is flammable and explosive. To reduce the risk of death or serious
injury, take the following precautions 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 matc h 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 battery in
a garage or closed room where th ere 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 fe el 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 fol-
low the procedure above if necessary.
●If you accidentally swallow electrolyte
Drink a large quantity of water or milk. Get emergenc y medical attention immedi-
ately.
■When handling the 12-volt battery
P. 572

4886-3. Do-it-yourself maintenance
RX450h_U_OM0E013U
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.
◆Installing tire pressure warning valves and transmitters
When replacing tires or wheels, tire pr essure warning valves and transmitters
must also be installed.
When new tire pressure wa rning 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 initia lized. Have tire pressure warning valve
and transmitter ID codes registered by your Lexus dealer. ( P. 489)
◆Initializing the tire pressure warning system
■The tire pressure warning system must be initialized in the following circum-
stances:
●When the tire inflation pressure is changed such as when changing travel-
ing 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 pressure.
Tire pressure warning system
●The tire pressure detected by the tire
pressure warning system can be dis-
played on the multi-information display.
The illustration used is intended as an exam-
ple, and may differ from the image that is
actually displayed on the multi-information
display.
●If the tire pressure drops below a prede-
termined level, the driver is warned by a
screen display and a warning light.
( P. 538)
The illustration used is intended as an exam-
ple, and may differ from the image that is
actually displayed on the multi-information
display.

4896-3. Do-it-yourself maintenance
6
Maintenance and care
RX450h_U_OM0E013U
■How to initialize the tire pressure warning systemPark the vehicle in a safe place and turn the power switch off.
Initialization cannot be performed while the vehicle is moving.
Adjust the tire inflation pressure to th e specified cold tire inflation pressure
level. ( P. 589)
Make sure to adjust the tire pressure to the specified cold tire inflation pressure
level. The tire pressure warning system will operate based on this pressure level.
Turn the power switch to ON mode.
Select on the multi-information display. ( P. 109)
Press or of the meter con-
trol switch, select the “TPMS”
screen and then press and hold
the
until the tire pressure
warning light blinks slowly 3
times.
“- -” will be displayed for inflation
pressure of each tire on the multi-
information displa y while the tire
pressure warning system determines
the position of each tire.
When position of each tire is determined, the inflation pressure of each tire will be
displayed on the mult i-information display.
Drive the vehicle at approximately 25 mph (40 km/h) or more for approx-
imately 10 to 30 minutes until the inflat ion pressure of each tire is displayed
on the multi-information display.
If tire inflation pressure becomes low before the inflation pressure is displayed, the
tire pressure warning light will come on.
Depending on the vehicle and driving co nditions, initialization may take up to
approximately 1 hour to complete.
◆Registering ID codes
The tire pressure warning valve and tran smitter is equipped with a unique ID
code. When replacing a tire pressure warning valve and transmitter, it is nec-
essary to register the ID code. Have the ID code registered by your Lexus
dealer.
1
2
3
4
5
6

4916-3. Do-it-yourself maintenance
6
Maintenance and care
RX450h_U_OM0E013U
■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 road s, the use of snow tires is recommended.
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, how-
ever, do not have adequate traction perfor mance compared with snow tires in heavy
or loose snow. Also, all season tires fall short in acceleration and handling perfor-
mance 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 ti res of the same size, construction and load capacity as the
originally installed tires. Since your vehicle has radial tires as original equipment, make
sure your snow tires also have radial cons truction. Do not install studded tires without
first checking local regulations for possible restrictions. Snow tires should be installed
on all wheels. ( P. 390)
■Initializing the tire pressure warning system
Initialize the system with the tire inflation pressure adjusted to the specified level.
■If the tread on snow tires wears down below 0.16 in. (4 mm)
The effectiveness of the tires as snow tires is lost.
■If you press the tire pressure warning reset switch accidentally
If initialization is performed, adjust the tire inflation pressure to the specified level and ini-
tialize the tire pressure warning system again.

4926-3. Do-it-yourself maintenance
RX450h_U_OM0E013U
■Situations in which the tire pressure warning system may not operate properly
●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.
• If a window tint that affects th e 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 extr emely 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 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 st rong 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 correctl y 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 pressure declines rapidly for example when a tire has burst, the
warning may not function.
■The initialization operation
●Make sure to carry out initialization afte r adjusting the tire inflation pressure.
Also, make sure the tires are cold before carryi ng out initialization or tire inflation pres-
sure adjustment.
●If you have accidentally turned the power switch off during initialization, it is not neces-
sary 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 re set switch when initialization is not necessary, adjust the
tire inflation pressure to the specified leve l when the tires are cold, and conduct initial-
ization again.
●While the position of each tire is being de termined and the inflation pressures are not
being displayed on the multi-info rmation display, if the inflation pressure of a tire drops,
the tire pressure warning light will come on.