2023 TOYOTA MIRAI cooling

822-1. Fuel cell electric vehicle
Owners Manual_USA_M62064_en
■High-voltage and high-temperature components
The fuel cell electric vehicle has high-voltage components (abo ut
650 V maximum) such as a fuel c ell stack, traction battery, power
control unit, fuel cell converter, high-voltage cables (which a re distin-
guished from low-voltage cables b y their orange covers), electric
motor (traction motor), etc., and high-temperature parts such a s the
radiator for cooling. Pay attention to all warning labels attached to
the vehicle.
This diagram is for illustrative purposes only and may differ f rom the actual
vehicle.
Warning label
Radiator for inverter cooling
Radiator for fuel cell stack cooling
Fuel cell water pump
Fuel cell converter and auxiliary inverter
Power control unit
Cabin coolant heater
Traction battery
Service plug

842-1. Fuel cell electric vehicle
Owners Manual_USA_M62064_enhydrogen tanks or valves need to
be disposed.
■Fuel cell stack coolant
●Fuel cell stack coolant uses a spe-
cifically-designed fluid with high
electrical insulation properties, in
order to safely cool the high-volt-
age fuel cell stack.
●Never add water or other coolants
to the fuel cell st
ack cooling sys-
tem, as they will cause permanent
damage.
●Consult your Toyota dealer for
replenishing or changing the fuel
cell stack coolant.
■Ion filter
●An ion filter is inst alled in the cool-
ant lines for the fuel cell stack, in
order to maintain the normal insu-
lation properties of the coolant.
●It is necessary to periodically
change the ion filter. ( P.466)
Contact your Toyota dealer for this
periodic maintenance.
■Tailpipe
●When the power switch is turned
off and the fuel cell system is
stopped ( P.182) after driving,
exhaust water is discharged. Be
careful when standing behind the
vehicle to avoid dripping or spray-
ing.
●It is possible to manually purge
the exhaust. Thi s may be desir-
able, for instance, before parking
in a garage. This is done by press-
ing the H
2O switch. ( P.196)
●On cold days, water vapor in the
exhaust may appe ar as a white
mist emitted from the tailpipe. This
is not a malfunction. A white mist
may be emitted from the vehicle
side depending on the wind direc-
tion. If it is a concern, consult with
a Toyota dealer.
●If the tailpipe is blocked, the fuel
cell system will stop.
●In the following state when cold, a white mist may be emitted. Water
vapor is being emitted as a sys-
tem protection and it is not a mal-
function.
• If several minutes have passed after opening the fuel lid, such as
refueling.
• Several hours have passed after the power switch was turned off.
■Hydrogen detectors
When the power switch is turned to
ON, the hydrogen detectors are
activated.
■Power output restriction
When the power output is restricted,
the vehicle may fa il to accelerate or
even decelerate, even though the
accelerator pedal is depressed. If a
safe driving speed cannot be main-
tained, stop the ve hicle in a safe
place away from the traffic. This
may be caused by the following con-
ditions:
●The coolant temperature may be
too high. This can be caused by
driving conditions such as
repeated sudden acceleration and
deceleration, continuous driving
on an incline, continuous driving
at high altitudes with a high load,
etc. In such situations, “FCV sys-
tem overheated Output power
reduced” is displayed on the multi-
information display, and the power
output is restricted. Once the cool-
ant returns to normal temperature,
the power output will retu rn to nor-
mal. ( P.464)
●The remaining fuel may be low.
After the low fuel level warning
light comes on, the output power
will be gradually restricted in order
to extend the possible driving dis-
tance. Once getting to this point,
the remaining driving distance
possible is short. Immediately refill
the vehicle with hydrogen.
●On cold days, the low fuel level
warning light comes on faster than
usual and the output power is
restricted.

902-1. Fuel cell electric vehicle
Owners Manual_USA_M62064_en
■If a warning light comes on, a
warning message is displayed,
or the 12-volt battery connec-
tion is disconnected
The fuel cell system may not be
able to restart.
If the “READY” indicator does not
come on, even when the start pro-
cedure is repeated, contact your
Toyota dealer.
There are air intake vents on
each side of the rear seatback
with the purpose of cooling the
traction battery. If the vents are
blocked, it may interfere with the
cooling of the traction battery.
If input/output of the traction battery
becomes limited and the distance
that the vehicle can be driven using
the traction motor is reduced, the
fuel economy may be reduced.
Traction battery air intake
vents
NOTICE
■Traction battery air intake
vents
●Make sure not to block the air
intake vents with anything, such
as cover, or luggage. The
input/output of t he traction bat-
tery may be restricted, leading
to a reduction in traction battery
output and a malfunction.
●Periodically clean the air intake
vents to prevent them from clog-
ging. ( P.433)
●Do not get water or foreign
materials in the air intake vents
as this may cause a short circuit
and damage the traction bat-
tery.

912-1. Fuel cell electric vehicle
Owners Manual_USA_M62064_en
2
Fuel cell systemMaintaining the Fuel cell System
Indicator to Eco area on the
multi-information display can
extend your driving range.
( P.103, 108)
Drive your vehicle smoothly.
Avoid abrupt acceleration and
deceleration.
Mild acceleration and decelera-
tion can help curb wasteful fuel
consumption.
If the brakes are operated gently
and in a timely manner, a
greater amount of electrical
energy can be regenerated
when slowing down.
Repeated acceleration and
deceleration, as well as long
waits at traffic lights, will lead to decreased fuel economy. Check
traffic reports before leaving and
avoid delays as much as possi-
ble. When driving in a con-
gested traffic situations, gently
release the brake pedal to allow
the vehicle to move forward
slightly while avoiding overuse
of the accelerator pedal. Doing
so can help control excessive
fuel consumption.
Similar to an electric vehicle, a
fuel cell electric vehicle uses the
most fuel in high output driving
such as driving on a steep uphill
or at high speeds. Moderate the
vehicle speed and maintain a
steady speed.
When using Eco drive mode, the
torque corresponding to the
accelerator pedal depression
amount can be generated more
smoothly than it is in normal
conditions. In addition, the oper-
ation of the air conditioning sys-
tem (heating/cooling) will be
minimized, improving the fuel
economy. (
P.320)
 Use the air conditioning only
when necessary. Doing so
Fuel cell electric vehi-
cle driving tips
To maximize fuel economy
and range, pay attention to
the following:
Use of Fuel cell System
Indicator
Accelerator pedal/brake
pedal operation
When braking
Delays
Driving with high power
output
Using Eco drive mode
Air conditioning

3205-5. Using the driving support systems
Owners Manual_USA_M62064_en
Multi-information display
Driving mode select switch
Driving mode changes if the switch
is pressed.
1 Normal mode
Provides an optimal balance of fuel
economy, quietness, and dynamic
performance. Suitable for normal
driving.
2Sport mode
Controls the transmission and fuel
cell system to provide quick, power-
ful acceleration. Making it suitable
for when agile dri ving response is
desired, such as when driving on
roads with many curves.
When the sport mod e is selected,
sport mode indicator comes on.
3 Eco drive mode
Helps the driver accelerate in an
eco friendly mann er and improve
fuel economy through moderate
throttle characteristics and by con-
trolling the operation of the air con-
ditioning system (heating/ cooling).
When the Eco drive mode is
selected, Eco drive mode indicator
comes on.
■Operation of the air condition-
ing system in Eco drive mode
Eco drive mode con trols the heat-
ing/ cooling operations and fan
speed of the air conditioning system
to enhance fuel efficiency. To
improve air conditioning perfor-
mance, perform the following opera-
tions:
●Turn off eco air conditioning mode
(  P.334, 341)
●Adjust the fan speed ( P.333,
341)
●Turn off Eco drive mode
■Automatic deactivation of sport
mode
If the power switch is turned off after
driving in sport mode, the drive
mode will be change d to normal
mode.
Driving mode select
switch
The driving modes can be
selected to suit driving con-
dition.
Selecting a drive mode

3346-1. Using the air conditioning system and defogger
Owners Manual_USA_M62064_en
and the fan speed decrease
switch to decrease the fan
speed.
Press the “OFF” switch to turn the
fan off.
■Change the airflow mode
Press the airflow mode control
switch.
The airflow mode changes as fol-
lows each time the switch is
pressed.
1 Air flows to the upper body.
2 Air flows to the upper body
and feet.
3 Air flows to the feet.
4 Air flows to the feet and the
windshield defogger oper-
ates.
■Switching between outside
air and recirculated air
modes
Press the outside/recirculated
air mode switch.
The mode switches between out-
side air mode and recirculated air
mode each time the switch is oper- ated.
When recirculated air mode is
selected, the indicator illuminates
on the outside/recirculated air
mode switch.
■Set cooling and dehumidifi-
cation function
Press the “A/C” switch.
When the function is on, the indica-
tor illuminates on the “A/C” switch.
■Eco air conditioning mode
The air conditioning is controlled
with low fuel consumption priori-
tized such as reducing fan
speed, etc.
Press the eco air conditioning
mode switch.
When the eco air conditioning
mode is on, the indicator illumi-
nates on the eco air conditioning
mode switch.
■Defogging the windshield
Defoggers are used to defog the
windshield and front side win-
dows.
Press the windshield defogger
switch.
Set the outside/recirculated air
mode switch to outside air mode if
the recirculated air mode is used. (It
may switch automatically.)
To defog the windshield and the
side windows quickly, turn the air
flow and temperature up.
To return to the previous mode,
press the windshield defogger
switch again when the windshield is
defogged.

3356-1. Using the air conditioning system and defogger
Owners Manual_USA_M62064_en
6
Interior features
When the windshield defogger
switch is on, the indicator illumi-
nates on the windshield defogger
switch.
■Defogging the rear window
and outside rear view mir-
rors
Defoggers are used to defog the
rear window and to remove rain-
drops, dew and frost from the
outside rear view mirrors.
Press the rear window and out-
side rear view mirror defoggers
switch.
The defoggers will automatically
turn off after 15 minutes.
When the rear window and outside
rear view mirror defoggers switch is
on, the indicator illuminates on the
rear window and ou tside rear view
mirror defoggers switch.
■When the outside temperature
exceeds 75°F (24°C) and the air
conditioning system is on
●In order to reduce the air condi-
tioning power consumption, the air
conditioning system may switch to
recirculated air mode automati-
cally.
This may also reduce fuel con-
sumption.
●Recirculated air mode is selected
as a default mode when the power
switch is turned to ON.
●It is possible to switch to outside
air mode at any time by pressing
the outside/recirculated air mode
switch.
■Fogging up of the windows
●The windows will easily fog up
when the humidity in the vehicle is
high. Turning the cooling and
dehumidification function on will dehumidify the air from the outlets
and defog the windshield effec-
tively.
●If you turn the cooling and dehu-
midification function off, the win-
dows may fog up more easily.
●The windows may fog up if the
recirculated air mode is used.
■When driving on dusty roads
Close all windows. If dust thrown up
by the vehicle is still drawn into the
vehicle after closing the windows, it
is recommended that the air intake
mode be set to outside air mode and
the fan speed to a ny setting except
off.
■Outside/recirculated air mode
●Setting to the recirculated air
mode temporarily is recom-
mended in preventing dirty air
from entering the vehicle interior
and helping to c ool the vehicle
when the outside air temperature
is high.
●Outside/recirculated air mode may
automatically switch depending on
the temperature setting or the
inside temperature.
■When the outside temperature
falls to nearly 32°F (0°C)
The dehumidification function may
not operate even when “A/C” switch
is pressed.
■Operation of the air condition-
ing system in Eco drive mode
●In Eco drive mode, the air condi-
tioning system is controlled as fol-
lows to prioritize fuel efficiency:
• Fuel cell system and compressor
operation controlled to restrict
heating/cooling capacity
• Fan speed restri cted when auto-
matic mode is selected
●To improve air conditioning perfor-
mance, perform the following
operations:
• Adjust the fan speed
• Turn off Eco drive mode ( P.320)
• Turn off Eco air conditioning mode

3416-1. Using the air conditioning system and defogger
Owners Manual_USA_M62064_en
6
Interior features
*: If equipped
■Adjusting the temperature
setting
Press of the temperature
control switches on the air con-
ditioning control panel to
increase the temperature.
Press of the temperature
control switches on the air con-
ditioning control panel to
decrease the temperature.
If the switch is pr essed and held or
selected and held, the temperature
will continuously change.
If the “A/C” indicat or is turned off,
the system will blow ambient tem-
perature air or heated air. ( P.346)
■Setting the fan speed
Press the fan speed increase
switch on the air conditioning
control panel to increase the fan
speed.
Press the fan speed decrease
switch on the air conditioning
control panel to decrease the
fan speed.
Press the “OFF” switch on the air
conditioning control panel to turn
the fan off.
■Change the airflow mode
Select the airflow mode control
switch on the air conditioning
control screen.
The airflow mode changes each
time the switch is selected.
: Air flows to the upper body
: Air flows to the upper body
and feet
: Air flows to the feet
: Air flows to the feet and the
windshield defogger operates
■Switching between outside
air and recirculated air
modes
Select the outside/recirculated
air mode switch on the air condi-
tioning control screen.
The mode switches between out-
side air mode and recirculated air
mode each time the switch is
selected.
When recirculated air mode is
selected, the indicator illuminates
on the outside/recirculated air
mode switch.
■Set cooling and dehumidifi-
cation function
Select the “A/C” switch on the
air conditioning control screen.
When the function is on, the indica-
tor illuminates on the “A/C” switch.
■Eco air conditioning mode
The air conditioning is controlled
with low fuel consumption priori-
tized such as reducing fan
speed, etc.
Select the eco air conditioning
mode switch on the air condi-
tioning control screen.