2023 TOYOTA MIRAI battery

4057-3. Do-it-yourself maintenance
Owners Manual_USA_M62064_en
7
Maintenance and care
Tire inflation
pressure
(  P.428)• Tire pressure
gauge
• Compressed air source
Washer fluid
( P.412)
• Water or washer
fluid containing
antifreeze (for
winter use)
• Funnel (used only for adding
water or washer
fluid)
WARNING
The fuel cell unit compartment
contains many mechanisms and
fluids that may move suddenly,
become hot, or become electri-
cally energized. To avoid death or
serious injury, observe the follow-
ing precautions.
■When working on the fuel cell
unit compartment
●Be careful not to touch the high-
voltage parts or hydrogen-
related parts.
●Make sure that the “READY”
indicator is off.
●Keep hands, clothing and tools
away from the moving fan.
●Be careful not to touch the
motor, inverter, radiator, etc.
right after driving as they may
be hot. Coolant and other fluids
may also be hot.
●Do not leave anything that may
burn easily, such as paper and
rags, in the fuel cell unit com-
partment.
ItemsParts and tools●Do not smoke, cause sparks or
expose an open flame to the 12-
volt battery. 12-volt battery
fumes are flammable.
●Be extremely cautious when
working on the 12-volt battery. It
contains poisonous and corro-
sive sulfuric acid.
●Take care because brake fluid
can harm your hands or eyes
and damage painted surfaces. If
fluid gets on your hands or in
your eyes, flush the affected
area with clean water immedi-
ately.
If you still experience discom-
fort, consult a doctor.
●Never touch, disassemble,
remove or replace the high-volt-
age parts, cables and their con-
nectors. It can cause severe
burns or electric shock that may
result in death or serious injury.
■When working near the elec-
tric cooling fan or radiator
grille
Be sure the power switch is off.
With the power switch in ON, the
electric cooling fa n may automati-
cally start to run if the air condi-
tioning is on and/or the coolant
temperature is high. ( P. 4 1 1 )
■Safety glasses
Wear safety glasses to prevent
flying or falling material, fluid
spray, etc. from getting in your
eyes.
NOTICE
■If you remove the air cleaner
filter
Driving with the air cleaner filter
removed may cause excessive
motor wear due to dirt in the air.

4087-3. Do-it-yourself maintenance
Owners Manual_USA_M62064_en
Inverter coolant reservoir ( P.411)
Fuel cell stack coolant reservoir ( P.411)
Fuse boxes ( P.438)
Brake fluid reservoir ( P.412)
Washer fluid tank ( P.412)
Inverter coolant radiator ( P.411)
Electric cooling fan
Condenser ( P.411)
Fuel cell stack coolant radiator ( P. 4 1 1 )
■12-volt battery
 P. 4 1 3
Fuel cell unit compartment
Components

4137-3. Do-it-yourself maintenance
Owners Manual_USA_M62064_en
7
Maintenance and care
The 12-volt battery is located in
the right-hand side of the trunk.
Remove the luggage mat: P. 3 6 1
■Before recharging
When recharging, the 12-volt bat-
tery produces hydrogen gas which
is flammable and explosive. There-
fore, observe the following precau-
tions before recharging:
●If recharging with the 12-volt bat-
tery installed on the vehicle, be
sure to disconnect the ground
cable.
●Make sure the power switch on
the charger is off when connecting
and disconnecting the charger
cables to the 12-volt battery.
■After recharging/reconnecting
the 12-volt battery
●Unlocking the doors using the
smart key system may not be pos-
sible immediately after reconnect-
ing the 12-volt battery. If this
happens, use the wireless remote
control or the mechanical key to
lock/unlock the doors.
●Start the fuel cell system with the
power switch in ACC. The fuel cell
system may not start with the
power switch turned off. However,
the fuel cell system will operate
normally from the second attempt.
WARNING
■When adding washer fluid
Do not add washer fluid when the
fuel cell system is hot or operating
as washer fluid contains alcohol
and may catch fire if spilled on the
fuel cell system, etc.
NOTICE
■Do not use any fluid other
than washer fluid
Do not use soapy water or anti-
freeze instead of washer fluid.
Doing so may cause streaking on
the vehicle’s painted surfaces, as
well as damaging the pump lead-
ing to problems of the washer
fluid not spraying.
■Diluting washer fluid
Dilute washer fluid with water as
necessary.
Refer to the freezing tempera-
tures listed on the label of the
washer fluid bottle.
12-volt batter y
Location

4147-3. Do-it-yourself maintenance
Owners Manual_USA_M62064_en
●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 dis-
connected. Make sure to turn off
the power switch before discon-
necting the 12-volt battery. Take
extra care when connecting the
12-volt battery if the power switch
mode prior to discharge is
unknown.
●When the 12-volt b attery is recon-
nected, start the fuel cell system,
depress the brake pedal, and con-
firm that it is possible to shift into
each shift position.
If the system will not start even after
multiple attempts, contact your Toy-
ota dealer.
WARNING
■Chemicals in the 12-volt bat-
tery
The 12-volt battery contains poi-
sonous and corrosi ve sulfuric acid
and may produce hydrogen gas
which is flammable and explosive.
To reduce the risk of death or seri-
ous injury, take th e following pre-
cautions while working on or near
the 12-volt battery:
●Do not cause sparks by touch-
ing 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 electro-
lyte.
●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 insuf-
ficient ventilation.
■Emergency measures regard-
ing 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 near-
est medical facility.
●If electrolyte gets on your skin
Wash the affected area thor-
oughly. If you feel pain or burn-
ing, get medical attention
immediately.
●If electrolyte gets on your
clothes
It can soak through clothing on
to your skin. Imm ediately take
off the clothing and follow the
procedure above if necessary.
●If you accidentally swallow elec-
trolyte
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. Failu re to do so may
cause gas (hydrogen) to enter the
passenger compartment, causing
a fire or explosion.
For replacement of the 12-volt
battery, contact your Toyota
dealer.

4157-3. Do-it-yourself maintenance
Owners Manual_USA_M62064_en
7
Maintenance and care
Make sure that the 12-volt bat-
tery terminals are not corroded
and that there are no loose con-
nections, cracks, or loose
clamps. Terminals
Hold-down clamp
Check the 12-volt battery condi-
tion by indicator color. Blue: Good condition
Red: Charging is necessary.
Have the vehicle inspected
by your Toyota dealer.
Clear: Replacement is nec-
essary.
Have the 12-volt battery
checked by your Toyota
dealer.
NOTICE
■When recharging the 12-volt
battery
Never recharge the 12-volt bat-
tery while the fue l cell system is
operating. Also, be sure all acces-
sories are turned off.
Exterior
Checking the 12-volt bat-
tery condition

4337-3. Do-it-yourself maintenance
Owners Manual_USA_M62064_en
7
Maintenance and care
areas with heavy traffic flow, early
replacement may be required. (For
scheduled maintenance information,
please refer to the “Scheduled
Maintenance Guide” or “Owner’s
Manual Supplement”.)
■If air flow from the vents
decreases dramatically
The filter may be clogged. Check
the filter and replace if necessary.
■Air conditioning filter with
deodorizing function
When fragrances are placed in your
vehicle, the deodorizing effect may
become significantly weakened in a
short period.
When an air conditioning odor
comes out continuously, replace the
air conditioning filter.
■Scheduled maintenance of the
air intake vents is necessary
when
In some situations such as when the
vehicle is used frequently or in
heavy traffic or dusty areas, the air
intake vents may need to be
cleaned more regularly.
For details, refer to the “Owner’s
Warranty Information Booklet” or
“Owner’s Manual Supplement”.
■Cleaning the air intake vents
Improper handling of the air intake
vent covers and filt ers may result in
damage to them. If you have any
concerns about cleaning the filter,
contact your Toyota dealer.
NOTICE
■When using the air condition-
ing system
Make sure that a filter is always
installed.
Using the air conditioning system
without a filter may cause damage
to the system.
■To prevent damage to the fil-
ter cover
When moving the filter cover in
the direction of arrow to release
the fitting, pay attention not to
apply excessive force to the
claws. Otherwise, the claws may
be damaged.
Cleaning the traction
batter y air intake
vents
To prevent the fuel economy
from being affected, visually
inspect the traction battery
air intake vents periodically
for clogs. If it is dusty or
clogged or if “Maintenance
Required for Traction Bat-
tery Cooling Parts See
Owner’s Manual” is shown
on the multi-information
display, clean the air intake
vents using the following
procedures:

4347-3. Do-it-yourself maintenance
Owners Manual_USA_M62064_en
1Turn the power switch off.
2 Remove the grille.
3 Remove the filter from the air
intake vent grille.
If dust has accumu lated on the air
intake vent grille, remove t he dust
with a vacuum cleaner, etc.
4 Remove the dust and sand
from the filter.
Using a vacuum cleaner, etc.,
absorb dust and sand from the filter
by profiling the nozzle lightly along
the fold.
5Hold the filter to the light and
check if it is not clogged.
If the dust or sand cannot be
removed completely, contact your
Toyota dealer.
6Reinstall the filter to the grille.
NOTICE
■If “Maintenance Required for
Traction Battery Cooling
Parts See Owner’s Manual” is
shown on the multi-informa-
tion display
Clean the air intake vents immedi-
ately.
If the vehicle is continuously
driven with the warning message
displayed, it may cause a mal-
function or output restriction of the
traction battery.
Cleaning procedure

4357-3. Do-it-yourself maintenance
Owners Manual_USA_M62064_en
7
Maintenance and care
7 Install the grille.
If “Maintenance Required for
Traction Battery Cooling Parts
See Owner’s Manual” was
displayed on the multi-infor-
mation display
8 Start the fuel cell system and
check that the warning mes-
sage is no longer displayed.
It may be necessary to drive the
vehicle for approximately 20 min-
utes before the warning message is
displayed again then disappears.
If the warning message does not
disappear after some time, have
the vehicle inspected by your Toy-
ota dealer.
■If the dust or sand on the filter
cannot be removed
It is recommended to use a vacuum
cleaner with plastic brushes.
WARNING
■When cleaning the air intake
vents
●Do not use water or other liq-
uids to clean the air intake
vents. If water is applied to the
traction battery or other compo-
nents, a malfunction or fire may
occur.
●Before cleaning the air intake
vents, make sure to turn the
power switch off to stop the fuel
cell system.
●Do not put a han d or leg in the
air intake vent. If it is caught in a
cooling fan, or if it touches a
high voltage part that results in
an electric shock, death or seri-
ous injuries may result.
■When removing the air intake
vent covers
Do not touch the service plug
located near the air intake vents.
(  P. 8 1 )
NOTICE
■When cleaning the air intake
vents
Do not use an ai r blow gun, etc.
Dust may be blown out, possibly
causing a malfunction or output
restriction of the traction battery.
■To prevent damage to the
vehicle
Observe the following precau-
tions:
●Do not allow wa ter or foreign
matter to enter the air intake
vent.
●Make sure to reinstall the filter
and cover to their original posi-
tions after cleaning.