2021 LEXUS RX450h warning light

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.

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

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

3966-3. Do-it-yourself maintenance
3Remove the fuse with the pullout
tool.
Only some fuses can be removed
using the pullout tool.
4 Check if the fuse is blown.
Normal fuse
Blown fuse
Replace the blown fuse with a new fuse of
an appropriate amperage rating. The
amperage rating can be found on the fuse
box lid.
Many types of fuse are used on this vehicle.
This illustration shows a common type of
fuse used on this vehicle.
■After a fuse is replaced
●If the lights do not turn on even after the
fuse has been replaced, a bulb may need
replacement. ( P.399)
●If the replaced fuse blows again, have the
vehicle inspected by your Lexus dealer.
■If there is an overload in a circuit
The fuses are designed to blow, protecting
the wiring harness from damage.
■When replacing light bulbs
Lexus recommends that you use genuine
Lexus products designed for this vehicle.
Because certain bulbs are connected to cir-
cuits designed to prevent overload,
non-genuine parts or parts not designed for
this vehicle may be unusable.
A
B
WARNING
■To prevent system breakdowns and
vehicle fire
Observe the following precautions.
Failure to do so may cause damage to
the vehicle, and possibly a fire or injury.
●Never use a fuse of a higher amperage
rating than that indicated, or use any
other object in place of a fuse.
●Always use a genuine Lexus fuse or
equivalent.
Never replace a fuse with a wire, even
as a temporary fix.
●Do not modify the fuses or fuse boxes.
■Fuse box near the power control unit
Never check or replace the fuses as
there are high voltage parts and wiring
near the fuse box.
Doing so may cause electric shock,
resulting in death or serious injury.

4076-3. Do-it-yourself maintenance
6
Maintenance and care
WARNING
■To prevent injury
Before performing any light bulb
replacement procedure, be sure to turn
the power switch off. Failure to do so may
result in burns from hot components or a
part of your body may get caught on an
operating component, possibly causing
serious injury.
■Replacing light bulbs
●Turn off the lights. Do not attempt to
replace the bulb immediately after
turning off the lights.
The bulbs become very hot and may
cause burns.
●Do not touch the glass portion of the
light bulb with bare hands. When it is
unavoidable to hold the glass portion,
use and hold with a clean dry cloth to
avoid getting moisture and oils on the
bulb.
Also, if the bulb is scratched or
dropped, it may blow out or crack.
●Fully install light bulbs and any parts
used to secure them. Failure to do so
may result in heat damage, fire, or
water entering the headlight unit. This
may damage the headlights or cause
condensation to build up on the lens.
●Do not attempt to repair or disassem-
ble the light bulbs, connectors, electric
circuits or component parts.
Doing so may result in death or serious
injury due to electric shock.
■To prevent damage or fire
●Make sure bulbs are fully seated and
locked.
●Check the wattage of the bulb before
installing to prev ent heat damage.