2020 LEXUS RC300 engine

2546-3. Do-it-yourself maintenance
Check the radiator, condenser and
intercooler radiator and clear away
any foreign objects.
If any of the above parts are extremely
dirty or you are not sure of their condi-
tion, have your vehicle inspected by
your Lexus dealer.
■Checking fluid level
The brake fluid level should be
between the “MAX” and “MIN” lines
on the tank.
RC350/RC300 AWD
RC300
■Adding fluid
Make sure to check the fluid type and
prepare the necessary item.
 Fluid type
SAE J1703 or FMVSS No.116 DOT 3
brake fluid
SAE J1704 or FMVSS No.116 DOT 4
brake fluid
Item
Clean funnel
WARNING
■When the engine is hot
Do not remove the engine coolant reser-
voir cap, intercooler coolant reservoir
cap and coolant inlet cap. ( P.314)
The cooling system may be under pres-
sure and may spray hot coolant if the cap
is removed, causing serious injuries, such
as burns.
NOTICE
■When adding coolant
Coolant is neither plain water nor
straight antifreeze. The correct mixture
of water and antifreeze must be used to
provide proper lubrication, corrosion
protection and cooling. Be sure to read
the antifreeze or coolant label.
■If you spill coolant
Be sure to wash it off with water to pre-
vent it from damagi ng parts or paint.
Checking the radiator, con-
denser and intercooler radiator
(if equipped)
WARNING
■When the engine is hot
Do not touch the radiator, condenser or
intercooler radiator as they may be hot
and cause serious injuries, such as burns.
Checking and adding the brake
fluid

2556-3. Do-it-yourself maintenance
6
Maintenance and care
■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.
Check the battery as follows.
■Battery exterior
Make sure that the battery terminals
are not corroded and that there are no
loose connections, cracks, or loose
clamps. Terminals
Hold-down clamp
■Before recharging
When recharging, the battery produces
hydrogen gas which is flammable and
explosive. Therefore, observe the following
before recharging:
●If recharging with the battery installed on
the vehicle, be sure to disconnect the
ground cable.
●Make sure the power switch on the char-
ger is off when connecting and discon-
necting the charger cables to the battery.
■After recharging/reconnecting the bat-
tery
The engine may not start. Follow the proce-
dure below to initialize the system.
1
Shift the shift lever to P.
2
Open and close either door.
3
Restart the engine.
●Unlocking the doors using the smart
access system with pu sh-button start may
not be possible immediately after recon-
necting the battery. If this happens, use
the wireless remote control or the
mechanical key to lock/unlock the doors.
●Start the engine with the engine switch in
ACCESSORY mode. The engine may
not start with the engine switch turned off.
However, the engine will operate nor-
mally from the second attempt.
●The engine switch mode is recorded by
the vehicle. If the battery is disconnected
and reconnected, the vehicle will return
the engine switch mode to the status it
was in before the battery was discon-
nected. Make sure to turn off the engine
before disconnecting the battery. Take
extra care when connecting the battery if
the engine switch mode prior to the bat-
tery being disconnected is unknown.
If the system will not start even after multi-
ple attempts, contact your Lexus dealer.
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 level in the accumulator
is high.
If the reservoir need s frequent refilling,
there may be a serious problem.
Battery
A
B

2566-3. Do-it-yourself maintenance
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.
RC350/RC300 AWD
WARNING
■Chemicals in the battery
Batteries contain poisonous and corro-
sive sulfuric acid and may produce
hydrogen gas which is flammable and
explosive. To reduce the risk of death or
serious injury, take the following precau-
tions while working on or near the bat-
tery:
●Do not cause sparks by touching the
battery terminals with tools.
●Do not smoke or light a match near the
battery.
●Avoid contact with eyes, skin and
clothes.
●Never inhale or swallow electrolyte.
●Wear protective safety glasses when
working near the battery.
●Keep children away from the battery.
■Where to safely charge the battery
Always charge the battery in an open
area. Do not charge the battery in a
garage or closed room where there is
insufficient ventilation.
■How to recharge the battery
Only perform a slow charge (5 A or
less). The 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 med-
ical 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 atten-
tion 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 neces-
sary.
●If you accidentally swallow electrolyte
Drink a large quantity of water or milk.
Get emergency medical attention imme-
diately.
NOTICE
■When recharging the battery
Never recharge the battery while the
engine is running. Also, be sure all acces-
sories are turned off.
Adding the washer fluid

2576-3. Do-it-yourself maintenance
6
Maintenance and care
RC300Check if the treadwear indicators are
showing on the tires. Also check the
tires for uneven wear, such as excessive
wear on one side of the tread.
Check the spare tire condition and
pressure if not rotated.
New tread
Worn tread
Treadwear indicator
The location of treadwear indicators is
shown by a “TWI” or “ ” mark, etc.,
molded into the sidewall of each tire.
Replace the tires if the treadwear indica-
tors are showing on a tire.
WARNING
■When adding washer fluid
Do not add washer fluid when the engine
is hot or running 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 anti-
freeze instead of washer fluid.
Doing so may cause streaking on the
vehicle’s painted surfaces, as well as
damaging the pump leading to problems
of the washer fluid not spraying.
■Diluting washer fluid
Dilute washer fluid with water as neces-
sary.
Refer to the freezing temperatures listed
on the label of the washer fluid bottle.
Tires
Replace or rotate tires in accor-
dance with maintenance schedules
and treadwear.
Checking tires
A
B
C

2596-3. Do-it-yourself maintenance
6
Maintenance and care
Vehicles with front and rear tires of
the same size
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 in terval as tire inspec-
tion.
Do not fail to initialize the tire pressure
warning system after tire rotation.
Vehicles with front and rear tires of
differing sizes
Tires cannot be rotated.
■When rotating the tires
Make sure that the engine switch is off. If the
tires are rotated while the engine switch is in
IGNITION ON mode, the tire position
WARNING
■When inspecting or replacing tires
Observe the following precautions to
prevent accidents.
Failure to do so may cause damage to
parts of the drivetrain 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-b elted 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.
NOTICE
■Low profile tires
Low profile tires may cause greater dam-
age than usual to the tire wheel when
sustaining impact from the road surface.
Therefore, pay attention to the following:
●Be sure to use proper tire inflation
pressure. If tires are under-inflated,
they may be damaged more severely.
●Avoid potholes, uneven pavement,
curbs and other road hazards. Failure
to do so may lead to severe tire and
wheel damage.
■If tire inflation pressure of each tire
becomes low while driving
Do not continue driving, or your tires
and/or wheels may be ruined.
■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.
Tire rotation

2606-3. Do-it-yourself maintenance
information will not be updated.
If this accidentally occurs, either turn the
engine switch to off and then to IGNITION
ON mode, or initialize the system after
checking that the tire pressure is properly
adjusted.
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.
 If the tire pressure drops below a
predetermined level, the driver is
warned by a screen display and a
warning light. ( P.289)
 The tire pressure detected by the
tire pressure warning system can be
displayed on the multi-information
display. ( P.69)
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.
■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.
• An auxiliary-supported run-flat tire is 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 tires not equipped with tire pressure warning valves and transmitters are 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 af fected 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.
Tire pressure warning system

2626-3. Do-it-yourself maintenance
■The tire pressure warning system
must be initialized in the following
circumstances:
 When rotating the tires.
 When the tire inflation pressure is
changed such as when changing
traveling speed.
 When changing the tire size.
When the tire pressure warning system
is initialized, the cu rrent 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 engine 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 th e 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 engine switch to IGNI-
TION ON mode.
4 Press and hold the tire pressure
warning reset switch until the tire pressure warning light blinks slowly
3 times.
5 Wait for a few minutes with the
engine switch in IGNITION ON
mode and then turn the engine
switch off.
■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 engine
switch off during initialization, it is not
necessary to press the reset switch again
as initialization will restart automatically
when the engine switch has been turned
to IGNITION 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.
■When initialization of the tire pressure
warning system has failed
Initialization ca n be completed in a few min-
utes. However, in the following cases, the
settings have not been recorded and the
system will not operate properly. If repeated
attempts to record tire inflation pressure
settings are unsuccessf ul, have the vehicle
inspected by your Lexus dealer.
●When operating the tire pressure warn-
ing reset switch, the tire pressure warning
light does not blink 3 times.
Initializing the tire pressure
warning system

2666-3. Do-it-yourself maintenance
1Turn the engine switch off.
2 Open the glove box. Lift up the side
with the stay, disconnect the stay
tabs and remove the partition by
pulling horizontally.
3 Press the tabs and remove the filter
cover. 4
Press the tabs and remove the filter
case.
5 Remove the air conditioning filter
from the filter case and replace it
with a new one.
The “ UP” marks shown on the filter
and the filter case sh ould be pointing up.
■Checking interval
Inspect and replace the air conditioning fil-
ter according to the maintenance schedule.
In dusty areas or areas with heavy traffic
flow, early replacement may be required.
(For scheduled maintenance information,
please refer to the “Owner’s Manual Sup-
plement” or “Scheduled Maintenance”.)
■If air flow from the vents decreases dra-
matically
The filter may be clogged. Check the filter
and replace if necessary.
■Air conditioning filt er with deodorizing
function
When fragrances are placed in your vehi-
cle, the deodorizing effect may become
significantly weakened in a short period.
Air conditioning filter
The air conditioning filter must be
changed regularly to maintain air
conditioning efficiency.
Removing the air conditioning
filter