2023 TOYOTA MIRAI battery replacement

3275-6. Driving tips
Owners Manual_USA_M62064_en
5
Driving
5-6.Driving tips
 Use washer fluid that is
appropriate to the prevailing
outside temperatures.
 Have a service technician
inspect the condition of the
12-volt battery.
 Have the vehicle fitted with
four snow tires or purchase a
set of tire chains for the rear
tires.
Ensure that all tires are the speci-
fied size and brand, and that chains
match the size of the tires.
Winter driving tips
Carry out the necessary
preparations and inspec-
tions before driving the
vehicle in winter. Always
drive the vehicle in a man-
ner appropriate to the pre-
vailing weather conditions.
Preparation for winter
WARNING
■Driving with snow tires
Observe the following precautions
to reduce the risk of accidents.
Failure to do so m ay result in a
loss of vehicle control and cause
death or serious injury.
●Use tires of the specified size.
●Maintain the recommended
level of air pressure.
●Do not drive in excess of 75
mph (120 km/h), regardless of
the type of snow tires being
used.
●Use snow tires on all, not just
some wheels.
■Driving with tire chains
Observe the following precautions
to reduce the risk of accidents.
Failure to do so may result in the
vehicle being unable to be driven
safely, and may cause death or
serious injury.
●Do not drive in excess of the
speed limit specifi ed for the tire
chains being used, or 30 mph
(50 km/h), whichever is lower.
●Avoid driving on bumpy road
surfaces or over potholes.
●Avoid sudden acceleration,
abrupt steering, sudden brak-
ing and shifting operations that
cause sudden regenerative
braking.
●Slow down sufficiently before
entering a curve to ensure that
vehicle control is maintained.
●Do not use LTA (Lane Tracing
Assist) system.
NOTICE
■Repairing or replacing snow
tires
Request repairs or replacement of
snow tires from Toyota dealers or
legitimate tire retailers.
This is because the removal and
attachment of snow tires affects
the operation of the tire pressure
warning valves and transmitters.

3376-1. Using the air conditioning system and defogger
Owners Manual_USA_M62064_en
6
Interior features
1 Press the “AUTO” switch.
2 Adjust the temperature set-
ting.
3 To stop the operation, press
the “OFF” switch.
If the fan speed setting or air
flow modes are operated, the
automatic mode indicator goes
off. However, automatic mode
for functions other than that
operated is maintained.
■Using automatic mode
Fan speed is adjusted automati-
cally according to the temperature
setting and the ambient conditions. Therefore, the fan may stop for a
while until warm or
cool air is ready
to flow immediately after the auto-
matic mode switch is pressed.
To turn on the “SYNC” mode,
press the “SYNC” switch.
The driver’s side temperature con-
trol knob can be used to adjust the
temperature for the driver’s and
passenger’s side. To enter individ-
ual mode, operate the passenger’s
side temperature control knob or
press the “SYNC” switch again.
When the “SYNC” mode is on, the
indicator illuminates on the “SYNC”
switch.
This feature is used to prevent
ice from building up on the wind-
shield and wiper blades.
Press the switch to turn the sys-
tem on/off.
The indicator comes on when the
system is on.
The windshield wiper de-icer will
automatically turn off after approxi-
mately 15 minutes.
WARNING
■When the outside rear view
mirror defoggers are operat-
ing
Do not touch the rear view mirror
surfaces when the outside rear
view mirror defoggers are on.
NOTICE
■To prevent 12-volt battery dis-
charge
Do not leave the air conditioning
system on longer than necessary
when the fuel cell system is off.
■When repairing/replacing
parts of the air conditioning
system
Have repair/replacement per-
formed by your Toyota dealer.
When a part of the air conditioning
system, such as the evaporator, is
to be replaced, it must be
replaced with a new one.
Using automatic mode
Adjusting the temperature
for driver and passenger
seats simultaneously
(“SYNC” mode)
Windshield wiper de-icer
(if equipped)

4007-2. Maintenance
Owners Manual_USA_M62064_en
7-2.Maintenance
■Repair and replacement
It is recommended that genuine
Toyota parts be used for repairs to
ensure performanc e of each sys-
tem. If non-Toyota parts are used in
replacement or if a repair shop other
than a Toyota dealer performs
repairs, confirm the warranty cover-
age.
■Allow inspection and repairs to
be performed by a Toyota
dealer
●Toyota technicians are well-
trained specialists and are kept up
to date with the latest service
information. They are well
informed about the operation of all
systems on your vehicle.
●Keep a copy of the repair order. It
proves that the maintenance that
has been performed is under war-
ranty coverage. If any problem
should arise while your vehicle is
under warranty, your Toyota
dealer will promptly take care of it.
General maintenance should be
performed on a daily basis. This
can be done by yourself or by a
Toyota dealer.
Scheduled maintenance should
be performed at specified inter-
vals according to the mainte-
nance schedule.
For details about maintenance
items and schedules, refer to the
“Scheduled Maintenance Guide” or
“Owner’s Manual Supplement”.
You can perform some mainte-
nance procedures by yourself.
Please be aware that do-it-your-
self maintenance may affect
Maintenance require-
ments
To ensure safe and econom-
ical driving, day-to-day care
and regular maintenance
are essential. It is the
owner’s responsibility to
perform regular checks.
Toyota recommends the
maintenance below.
WARNING
■If your vehicle is not properly
maintained
Improper maintenance could
result in serious damage to the
vehicle and possible death or seri-
ous injury.
■Handling of the 12-volt bat-
tery
●Oils, fuels and fluids contained
in vehicles as well as waste pro-
duced by component wear con-
tain or emit chemicals known to
the State of California to cause
cancer and birth defects or
other reproductive harm. Avoid
exposure and wash any
affected area immediately.
●12-volt battery posts, terminals
and related accessories con-
tain lead and lead compounds
which are known to cause brain
damage. Wash your hands after
handling. ( P.413)
General maintenance
Scheduled maintenance
Do-it-yourself mainte-
nance

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:

4367-3. Do-it-yourself maintenance
Owners Manual_USA_M62064_en
■If the electronic key battery is
depleted
The following symptoms may occur:
●The smart key system and wire-
less remote control will not func-
tion properly.
●The operational range will be
reduced.
 Flathead screwdriver
 Small flathead screwdriver
 Lithium battery CR2032
■Use a CR2032 lithium battery
●Batteries can be purchased at
your Toyota dealer, local electrical
appliance shops or camera stores.
●Replace only with the same or
equivalent type recommended by
the manufacturer.
●Dispose of used batteries accord-
ing to local laws.
NOTICE
●Do not install anything to the air
intake vent other than the exclu-
sive filter for this vehicle or use
the vehicle without the filter
installed.
■To prevent damage to the fil-
ter
Observe the following precau-
tions.
If the filter is damaged, have it
replaced with a new filter by your
Toyota dealer.
●Do not use an air blow gun, etc.
●Do not press hard a vacuum
cleaner, etc. against the filter.
●Do not use a hard brush, such
as a metal brush.
●Do not break the fold of the fil-
t er.
Electronic key batter y
Replace the battery with a
new one if it is depleted.
As the key may be damaged
if the following procedure is
not performed properly, it is
recommended that key bat-
tery replacement be per-
formed by your Toyota
dealer.
Items to prepare

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.