2021 LEXUS RX450h battery

3676-3. Do-it-yourself maintenance
6
Maintenance and care
6-3.Do-it-yourself maintenance
Do-it-yourself service pre-
cautions
If you perform maintenance by
yourself, be sure to follow the cor-
rect procedure as given in these
sections.
Maintenance
ItemsParts and tools
12-volt battery
condition
( P.376)•Grease
• Conventional
wrench (for terminal
clamp bolts)
Brake fluid level
( P.375)
• FMVSS No.116 DOT
3 or SAE J1703
brake fluid
•Rag or paper towel
• Funnel (used only for adding brake fluid)
Engine/power
control unit cool-
ant level
( P.373)
•“Toyota Super Long
Life Coolant” or a
similar high quality
ethylene gly-
col-based non-sili-
cate, non-amine,
non-nitrite and
non-borate coolant
with long-life hybrid
organic acid tech-
nology
For the U.S.A.:
“Toyota Super Long
Life Coolant” is
pre-mixed with 50%
coolant and 50%
deionized water.
For Canada:
“Toyota Super Long
Life Coolant” is
pre-mixed with 55%
coolant and 45%
deionized water.
•Funnel (used only for adding coolant)
Engine oil level
( P.371)
•“Toyota Genuine
Motor Oil” or equiv-
alent
• Rag or paper towel
•Funnel (used only for adding engine oil)
Fuses ( P.395)
•Fuse with same
amperage rating as
original
Headlight aim
( P.397)• Phillips-head screw-
driver
ItemsParts and tools

3716-3. Do-it-yourself maintenance
6
Maintenance and care
Washer fluid tank (P.375)
Brake fluid reservoir ( P.375)
Engine oil level dipstick ( P.372)
Engine coolant reservoir ( P.373)
Power control unit coolant reservoir ( P.373)
Fuse boxes ( P.395)
Radiator ( P.374)
Power control unit coolant radiator ( P.374)
Condenser ( P.374)
Electric cooling fans
Engine oil filler cap ( P.372)
■12-volt battery
 P.376
With the engine at operating tempera-
ture and turned off, check the oil level
Engine compartment
Components
A
B
C
D
E
F
G
H
I
J
K
Checking and adding the engine
oil

3766-3. Do-it-yourself maintenance
RX450h
The 12-volt battery is located in the
left-hand side of luggage compart-
ment.
RX450hL
The 12-volt battery is located in the
left-hand side of luggage compart-
ment.
RX450h
1 Lift the deck board and attach the
hook. ( P.331)
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.
12-volt battery
Location
Removing the 12-volt battery
cover

3776-3. Do-it-yourself maintenance
6
Maintenance and care
2Remove the cover after removing
the clips.
1 Press
2 Pull out
RX450hL
1 Remove the deck board and side
auxiliary box cover. ( P.332)
2 Remove the 12-volt battery cover.
3 Remove the deck side trim cover.
■Before recharging
When recharging, the 12-volt battery pro-
duces hydrogen gas which is flammable
and explosive. Therefore, observe the fol- lowing precautions before recharging:
●If recharging with the 12-volt battery
installed on the vehicle, be sure to discon-
nect the ground cable.
●Make sure the power switch on the char-
ger is off when connecting and discon-
necting 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 sys-
tem.
1 Shift the shift lever to P.
2 Open and close any of the doors.
3 Restart the hybrid system.
●Unlocking the doors using the smart
access system with pu sh-button start may
not be possible immediately after recon-
necting the 12-volt battery. If this hap-
pens, use the wireless remote control or
the mechanical key to lock/unlock the
doors.
●Start the hybrid system with the power
switch in ACCESSORY mode. The
hybrid system may not start with the
power switch turned off. However, the
hybrid system will operate normally from
the second attempt.
●The power switch mode is recorded by
the vehicle. If the 12-volt battery is recon-
nected, the vehicle will return the power
switch mode to the stat us 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 connecting the 12-volt battery
if the power switch mode prior to dis-
charge is unknown.
If the system will not start even after multiple
attempts at all the methods above, contact
your Lexus dealer.

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.

3796-3. Do-it-yourself maintenance
6
Maintenance and care
RX450h
Make sure that the 12-volt battery ter-
minals are not corroded and that there
are no loose connections, cracks, or
loose clamps.
Terminals
Hold-down clamp
RX450hL
Make sure that the 12-volt battery ter-
minals are not corroded and that there
are no loose connections, cracks, or
loose clamps.
Terminals
Hold-down clamp
RX450h
Install the 12-volt battery cover with the
clips.
1 Push up center position
2 Insert
3 Press
RX450hL
1 Install the deck side trim cover.
2 Install the 12-volt battery cover.
Exterior
A
B
A
B
Installing the 12-volt battery
cover

3936-3. Do-it-yourself maintenance
6
Maintenance and care
■Replacing the rear wiper insert
Have the rear wiper inse rt replaced by your
Lexus dealer.
■Handling of the windshield wiper blades
and inserts
Improper handling of the windshield wiper
blades and inserts may cause them to be
damaged. If it is difficult to follow the wiper
blade and insert replacement procedure
precisely, contact your Lexus dealer.
■If the electronic key battery is depleted
The following symptoms may occur:
●The smart access system with push-but-
ton start and wireless remote control will
not function properly.
●The operationa l range will be reduced.
Flathead screwdriver
 Lithium battery CR2032
■Use a CR2032 lithium battery
●Batteries can be purchased at your Lexus
dealer, local electrical appliance shops or
camera stores.
●Replace only with the same or equivalent
type recommended by the manufacturer.
●Dispose of used batteries according to
the local laws.
1Take out the mechanical key.
2 Remove the cover.
To prevent damage to the key, cover the tip
Electronic key battery
Replace the battery with a new one
if it is depleted.
You will need the following items:
Replacing the battery

3946-3. Do-it-yourself maintenance
of the flathead screwdriver with a tape.
3Remove the depleted battery.
When removing the cover, the electronic
key module may stick to the cover and the
battery may not be visible. In this case,
remove the electronic key module in order
to remove the battery.
Insert a new battery with the “+” terminal
facing up.
WARNING
■Battery precautions
Observe the following precautions.
Failure to do so may result in death or
serious injury.
●Do not swallow the battery. Doing so
may cause chemical burns.
●A coin battery or button battery is
used in the electronic key. If a battery is
swallowed, it may cause severe chemi-
cal burns in as little as 2 hours and may
result in death or serious injury.
●Keep away new and removed batteries
from children.
●If the cover cannot be firmly closed,
stop using the electronic key and stow
the key in the place where children
cannot reach, and then contact your
Lexus dealer.
●If you accidentally swallow a battery or
put a battery into a part of your body,
get emergency medical attention
immediately.
■To prevent battery explosion or leak-
age of flammable liquid or gas
●Replace the battery with a new battery
of the same type. If a wrong type of
battery is used, it may explode.
●Do not expose batteries to extremely
low pressure due to high altitude or
extremely high temperatures.
●Do not burn, break or cut a battery.
NOTICE
■For normal operation after replacing
the battery
Observe the following precautions to
prevent accidents:
●Always work with dry hands.
Moisture may cause the battery to
rust.
●Do not touch or move any other com-
ponent inside the remote control.
●Do not bend either of the battery ter-
minals.