2023 TOYOTA MIRAI cooling

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.

4668-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
■If a message that indicates the
need for visiting your Toyota
dealer is displayed
The system or part shown on the
multi-information display is malfunc-
tioning. Have the vehicle inspected
by your Toyota dealer immediately.
■If a message that indicates the
need for referring to Owner’s
Manual is displayed
●If any of the following messages
are shown on the multi-informa-
tion display, it may indicate a mal-
function. Have the vehicle
inspected by you r Toyota dealer
immediately.
• “Smart Key System Malfunction
See Owner’s Manual”
• “P Switch Malfunction Apply Park- ing Brake Securely When Parking
See Owner’s Manual”
• “Shift System Malfunction Apply Parking Brake Securely When
Parking See Owner’s Manual”
• “Shift System Unavailable Apply Parking Brake Securely When
Parking See Owner’s Manual”
• “Shift System Malfunction See Owner’s Manual”
• “Shift System Malfunction Stop in a Safe Place See Owner’s Man-
ual”
• “Battery Low Shifting Unavailable See Owner’s Manual”
• “FCV system malfunction”
• “Traction battery system malfunc-
tion”
• “Accelerator System Malfunction”
●If any of the following messages
are shown on the multi-informa-
tion display, it may indicate a mal-
function. Immediat ely stop the
vehicle and contact your Toyota
dealer.
• “Braking Power Low Stop in a Safe Place See Owner’s Manual”
• “FCV System Shutdown Due to
Hydrogen Leakage Stop in a Safe
Place See Owner’s Manual”
●If “FCV system stopped” is shown
on the multi-information display,
the vehicle may have run out of fuel. Stop the vehicle in a safe
place and, if the fuel level is low,
refuel the vehicle. (
P.83)
●If “Low Auxiliary Battery See
Owner’s Manual” is shown,
• When the display goes off after several seconds (displays for
about 6 seconds): Maintain the
fuel cell system operation for more
than 15 minutes and charge the
12-volt battery.
• When the display does not go off: Start up the fuel cell system using
the procedures: P. 4 8 5
●If “Maintenance Required for Trac-
tion Battery Cooling Parts See
Owner’s Manual” is shown, the fil-
ters may be clogged, the air intake
vents may be blocked, or there
may be a gap in the duct. There-
fore, perform the following correc-
tion procedure.
• Cleaning the traction battery air intake vents ( P.433)
If the warning message is shown
even if the vents are cleaned,
have the vehicle inspected by
your Toyota dealer.
■If “Ion Filter Maintenance
Required Visit Your Dealer” is
displayed
Ion filter replacement is necessary.
Contact your Toyota dealer.
NOTICE
■If “Low Auxiliary Battery See
Owner’s Manual” is displayed
frequently
The 12-volt battery may have
deteriorated. As the battery may
discharge in this state when left
unattended, have the battery
inspected by you r Toyota dealer.

4898-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
8
When trouble arises
WARNING
●When working with the 12-volt
battery, always wear safety
glasses and take care not to
allow any battery fluids (acid) to
come into contact with skin,
clothing or the vehicle body.
●Do not lean over the 12-volt bat-
tery.
●In the event that battery fluid
comes into contact with the skin
or eyes, immediately wash the
affected area with water and
seek medical attention. Place a
wet sponge or cloth over the
affected area until medical
attention can be received.
●Always wash your hands after
handling the 12-volt battery sup-
port, terminals, and other bat-
tery-related parts.
●Do not allow child ren near the
12-volt battery.
■After recharging the 12-volt
battery
Have the 12-volt battery
inspected at your Toyota dealer
as soon as possible.
If the 12-volt battery is deteriorat-
ing, continued use may cause the
12-volt battery to emit a malodor-
ous gas, which may be detrimen-
tal to the health of passengers.
■When replacing the 12-volt
battery
●When the vent plug and indica-
tor are close to the hold down
clamp, the battery fluid (sulfuric
acid) may leak.
●For information regarding 12-
volt battery rep lacement, con-
tact your Toyota dealer.
●After replacing, s ecurely attach
the exhaust hose and exhaust
hole plug to the exhaust hole of
the replaced 12-volt battery. If
not properly installed, gases
(hydrogen) may leak into the
vehicle interior, and there is the
possible danger of the gas ignit-
ing and exploding.
NOTICE
■When handling jumper cables
When connecting the jumper
cables, ensure that they do not
become entangled in the cooling
fan.
■When connecting jumper
cables
Make sure to connect jumper
cables to the specified terminals
and connecting point. Failure to
do so may adversely affect the
electronic devices or damage to
them.
■To prevent damaging the
vehicle
The exclusive jump starting termi-
nal is to be used when charging
the 12-volt battery from another
vehicle in an emergency. It cannot
be used to jump start another
vehicle.

4908-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
Label
Fuel cell stack coolant reservoir
Inverter coolant reservoir
If your vehicle overheats
The following may indicate that your vehicle is overheating.
The high coolant temperature warning light ( P.455) comes on
or flashes, or a loss of fuel cell system power is experienced.
(For example, the vehicle speed does not increase.)
 The fuel cell system overheat warning light ( P.455) comes on
 Steam comes out from under the hood.
Parts name for cooling components

4918-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
8
When trouble arises
If the high coolant tempera-
ture warning light comes on or
flashes
1 Stop the vehicle in a safe
place and turn off the air con-
ditioning system, and then
stop the fuel cell system.
2 If you see steam:
Carefully lift the hood after
the steam subsides.
If you do not see steam:
Carefully lift the hood.
3 After the fuel cell system has
cooled down sufficiently,
inspect the hoses and radia- tor core (radiator) for any
leaks.
Electric cooling fan
Fuel cell stack coolant radia-
tor
If a large amount of coolant leaks,
immediately contact your Toyota
dealer.
4
The fuel cell stack coolant
level is satisfactory if it is
between the “MAX” and
“MIN” lines on the reservoir.
Fuel cell stack coolant reser-
voir
“MAX” line
“MIN” line
If the amount of fuel cell stack
coolant is low:
Immediately contact your Toyota
dealer.
NOTICE
■Fuel cell stack coolant
The fuel cell stack coolant is
exclusive for fuel cell stack usage.
Damage may occur when water
or any other type of coolant is
used, so never use any other
fluid. If the fuel cell stack coolant
is low, immediately contact your
Toyota dealer.
Correction procedures

4928-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
If the amount of fuel cell stack
coolant is not low:
Have the vehicle inspected at
the nearest Toyota dealer.
Even if the fuel cell stack cool-
ant is low, do not refill it.
If the fuel cell system over-
heat warning light comes on
1 Stop the vehicle in a safe
place and turn off the air con-
ditioning system, and then
stop the fuel cell system.
2 If you see steam or coolant
leaks:
Carefully lift the hood after
the steam subsides.
If you do not see steam or
coolant leaks:
Carefully lift the hood.
3 After the fuel cell system has
cooled down, inspect the hoses and radiator core (radi-
ator) for any leaks.
Electric cooling fan
Inverter coolant radiator
If a large amount of coolant leaks,
immediately contact your Toyota
dealer.
4
The inverter coolant level is
satisfactory if it is between
the “MAX” and “MIN” lines on
the reservoir.
Inverter coolant reservoir
“MAX” line
“MIN” line
5 Add inverter coolant if neces-
sary.
Water can be used in an emer-
gency if inverter coolant is unavail-