2021 LEXUS ES300h battery

3216-3. Do-it-yourself maintenance
6
Maintenance and care
Fuse boxes (P.349)
Engine oil filler cap ( P.322)
Engine oil level dipstick ( P.321)
Brake fluid reservoir ( P.325)
Radiator ( P.324)
Electric cooling fan
Condenser ( P.324)
Power control unit coolant reservoir ( P.324)
Engine coolant reservoir ( P.323)
Washer fluid tank ( P.325)
■12-volt battery
 P.326
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
Checking and adding the engine
oil

3266-3. Do-it-yourself maintenance
The 12-volt battery is located on the
right-hand side of the trunk.
■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 dis-
connect 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
●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
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

3276-3. Do-it-yourself maintenance
6
Maintenance and care
switch mode to the status it was in before
the 12-volt battery was disconnected.
Make sure to turn off the power switch
before disconnect the 12-volt battery.
Take extra care when connecting the 12-
volt battery if the power switch mode
prior to discharge is unknown.
If the hybrid system will not start even after
multiple attempts at all methods above,
contact your Lexus dealer.
Lift the luggage mat up.
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
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 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
battery in a garage or closed room
where there is insufficient ventilation.
■How to recharge the 12-volt battery
Recharge at a current of 5 A or less and
make sure that the recharging period
does not exceed a total of 12 hours.
■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.
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.
Removing the 12-volt battery
cover

3286-3. Do-it-yourself maintenance
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
Check the 12-volt battery condition by
indicator color. Blue: Good condition
Red: Charging is necessary.Have the vehicle inspected by your Lexus
dealer.
Clear: Replacement is necessary.
Have the 12-volt battery checked by your
Lexus dealer.
Exterior
Checking 12-volt battery condi-
tion
A
B
A
B
C

3446-3. Do-it-yourself maintenance
Remove the dust from the air intake
vent with a vacuum cleaner, etc.
Make sure to only use a vacuum to suck
out dust and clogs. Attempting to blow out
dust and clogs using an airgun, etc. may
push it into the air intake vent. ( P.346)
If dust and clogs cannot be completely
removed with the air intake vent cover
installed, remove the cover and clean the filter.
1
Turn the power switch off.
2 Using a Phillips screwdriver,
remove the clip.
3 Remove the air intake vent cover.
1 Pull the cover as shown in the illus-
tration to disengage the 7 claws,
starting from the claw in the upper
right corner.
2 Pull the cover toward the front of
the vehicle to remove it.
Cleaning the hybrid battery
(traction battery) air intake
vent and filter
To prevent the fuel economy from
being affected, visually inspect the
hybrid battery (traction battery) air
intake vent periodically for dust and
clogs. If it is dusty or clogged or if
“Maintenance required for Trac-
tion battery cooling parts See
owner’s manual” is displayed on the
multi-information display, clean the
air intake vent using the following
procedures:
Cleaning the air intake vent
If dust and clogs cannot be com-
pletely removed

3466-3. Do-it-yourself maintenance
8Using a Phillips screwdriver, install
the clip.
■Scheduled maintenance of the air
intake vent is necessary when
In some situations such as when the vehicle
is used frequently or in heavy traffic or dusty
areas, the air intake vent may need to be
cleaned more regularly.
For details, refer to “Owner’s Manual Sup-
plement” or “Scheduled Maintenance”.
■Cleaning the air intake vent
●Dust in the air intake vent may interfere
with the cooling of the hybrid battery
(traction battery). If charging/discharg-
ing of the hybrid batt ery (traction battery)
becomes limited, the distance that the
vehicle can be driven using the electric
motor (traction motor) may be reduced
and the fuel economy may be reduced.
Inspect and clean the air intake vent peri-
odically.
●Improper handling of the air intake vent
cover and filter may result in damage to
them. If you have any concerns about
cleaning the filter, contact your Lexus
dealer.
■If “Maintenance required for Traction
battery cooling parts See owner’s man-
ual” is displayed on the multi-informa-
tion display
●If this warning message is displayed on
the multi-information display, remove the
air intake vent cover and clean the filter.
(  P.344)
●After cleaning the air intake vent, start
the hybrid system and check that the
warning message is no longer displayed.
After the hybrid system is started, it may be necessary to drive the vehicle up to
approximately 20 minutes before the
warning message disapp
ears. If the warn-
ing message does not disappear after
driving for appropri ately 20 minutes,
have the vehicle inspected by your Lexus
dealer.
WARNING
■When cleaning the air intake vent
●Do not use water or other liquids to
clean the air intake vent. If water is
applied to the hybrid battery (traction
battery) or other components, a mal-
function or fire may occur.
●Before cleaning the air intake vent,
make sure to turn the power switch off
to stop the hybrid system.
■When removing the air intake vent
cover
Do not touch the service plug located
near the air intake vent. ( P.65)
NOTICE
■When cleaning the air intake vent
When cleaning the air intake vent, make
sure to only use a vacuum to suck out
dust and clogs. If a compressed air blow
gun, etc. is used to blow out dust and
clogs, the dust or clogs may be pushed
into the air intake ve nt, which may affect
the performance of the hybrid battery
(traction battery) and cause a malfunc-
tion.

3476-3. Do-it-yourself maintenance
6
Maintenance and care
■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.
Prepare the following before replacing
the battery:
Flathead screwdriver
 Small 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.
NOTICE
■To prevent damage to the vehicle
●Do not allow water or foreign matter
to enter the air intake vent when the
cover is removed.
●Carefully handle the removed filter so
that it will not be damage.
If the filter is damaged, have it
replaced with a new filter by your
Lexus dealer.
●Make sure to reinst all the filter and
cover to their original positions after
cleaning.
●Do not install anything to the air intake
vent other than the exclusive filter for
this vehicle or use the vehicle without
the filter installed.
■If “Maintenance required for Trac-
tion battery cooling parts See
owner’s manual” is displayed on the
multi-information display
If the vehicle is continuously driven with
the warning message (indicating that
charging/discharging of the hybrid bat-
tery (traction battery) may become lim-
ited) displayed, the hybrid battery
(traction battery) may malfunction.
Electronic key battery
Replace the battery with a new one
if it is depleted.
Items to prepare
Replacing the battery

3486-3. Do-it-yourself maintenance
2Remove the cover.
To prevent damage to the key, wrap the tip
of the screwdriver with tape.
3Remove the depleted battery.
Insert a new battery with the “+” terminal
facing up.
WARNING
■Battery precautions
Observe the following precautions. Fail-
ure to do so may result in death or seri-
ous 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
chemical burns in as little as 2 hours
and may result in death or serious
injury.
●Keep away new and removed batter-
ies 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
■When replacing the battery
Use a screwdriver of appropriate size.
Applying excessive force may deform or
damage the cover.
■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.