2020 TOYOTA MIRAI cooling

4568-2. Steps to take in an emergency
MIRAI_OM_USA_OM62073U
WARNING
■12-volt battery precautions
The 12-volt battery contains poisonous and corrosive acidic ele ctrolyte,
while related parts contain lead and lead compounds. Observe th e following
precautions when handling the 12-volt battery:
● When working with the 12-volt battery, always wear safety glass es and
take care not to allow any 12-volt battery fluids (acid) to come into contact
with skin, clothing or the vehicle body.
● Do not lean over the 12-volt battery.
● In the event that 12-volt battery fluid comes into contact with the skin or
eyes, immediately wash the affected area with water and seek me dical
attention.
Place a wet sponge or cloth over the affected area until medica l attention
can be received.
● Always wash your hands after handling the 12-volt battery suppo rt, termi-
nals, and other battery-related parts.
● Do not allow children near the 12-volt battery.
■ After recharging the 12-volt battery
Have the 12-volt battery inspected at your Toyota dealer as soo n as possi-
ble.
If the 12-volt battery is deteriorating, continued use may caus e the 12-volt
battery to emit a malodorous gas, which may be detrimental to the health of
passengers.
■ When exchanging the 12-volt battery
After exchanging, securely attach the exhaust hose and exhaust hole plug
to the exhaust hole of the exchanged 12-volt battery. If not pr operly
installed, gases (hydrogen) may leak into the vehicle interior, and there is
the possible danger of the gas igniting and exploding.
■ When replacing the 12-volt battery
 P. 376
NOTICE
■To prevent damaging the vehicle
The exclusive jump starting terminal is to be used when chargin g the 12-volt
battery from another vehicle in an emergency. It cannot be used to jump
start another vehicle.
■ When handling jumper cables
When connecting the jumper cables, ensure that they do not beco me entan-
gled in the cooling fans.

4588-2. Steps to take in an emergency
MIRAI_OM_USA_OM62073U■
If the high coolant temperature warning light comes on or
flashes
Stop the vehicle in a safe place and turn off the air condition
ing sys-
tem, and then stop t he fuel cell system.
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.
After the fuel cell system has
cooled down sufficiently,
inspect the hoses and radiator
core (radiator) for any leaks.
Fuel cell stack coolant sub
radiator
Fuel cell stack coolant radia-
tor
Electric cooling fans
If a large amount of coolant leaks, immediately contact your Toyota
dealer.
NOTICE
Correction procedures
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, imme-
diately contact your Toyota dealer.
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4608-2. Steps to take in an emergency
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If “FC System Overheat Output P
ower is Limited” is displayed
on the multi-information display
Stop the vehicle in a safe place and turn off the air conditioning
system, and then stop th e fuel cell system.
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.
After the fuel cell system has
cooled down, inspect the
hoses and radiator core
(radiator) for any leaks.
Inverter coolant radiator
Electric cooling fans
If a large amount of coolant
leaks, immediately contact
your Toyota dealer.
The inverter coolant level is
satisfactory if it is between
the “FULL” and “LOW” lines
on the reservoir.Inverter coolant reservoir
“FULL”
“LOW”
Add inverter cool ant if neces-
sary.
Water can be used in an emer-
gency if inverter coolant is
unavailable.
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4618-2. Steps to take in an emergency
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8
When trouble arises
Start the fuel cell system and turn the air conditioning system on
to check that the radiator coo ling fans operate and to check fo r
coolant leaks from t he radiator or hoses.
The fans operate when the air conditioning system is turned on immedi-
ately after a cold start. Confirm that the fans are operating b y checking
the fan sound and air flow. If it is difficult to check these, turn the air con-
ditioning system on and off repeatedly.
(The fans may not operate in freezing temperatures.)
If the fans are not operating:
Stop the fuel cell system immed iately and contact your Toyota
dealer.
If the fans are operating:
Have the vehicle inspected at the neare st Toyota dealer.
WARNING
■When inspecting under th e hood of your vehicle
Observe the following precautions.
Failure to do so may result in serious injury such as burns.
● If steam is seen coming from under the hood, do not open the ho od until
the steam has subsided. The motor compartment may be very hot.
● After the fuel cell system has been turned off, check that the “READY”
indicator is off.
When the fuel cell system is operating, the cooling fans may suddenly
operate even if the fuel cell system stops. Do not touch or app roach rotat-
ing parts such as the fans, which may lead to fingers or clothing (espe-
cially a tie, a scarf or a muffler) getting caught, resulting i n serious injury.
● Do not loosen the coolant reservoir caps or radiator cap, while the fuel cell
system and radiator are hot.
High temperature steam or coolant could spray out.
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4628-2. Steps to take in an emergency
MIRAI_OM_USA_OM62073U
NOTICE
■When adding inverter coolant
Add coolant slowly after the fuel cell system has cooled down s ufficiently.
Adding inverter cool coolant to a hot fuel cell system too quic kly can cause
damage to the fuel cell system.
■ To prevent damage to the cooling system
Observe the following precautions:
● Avoid contaminating the coolant with foreign matter (such as sa nd or dust
etc.).
● Do not use any coolant additive with inverter coolant.
● For replacement of the fuel cell stack coolant, contact your Toyota dealer.
● Do not use water or any other coolant when refilling the fuel c ell stack
coolant. Also, do not use any additive agents for the coolant.

4699-1. Specifications
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9
Vehicle specifications
*: The fluid capacity is a reference quantity.If replacement is necessary, contact your Toyota dealer.
Cooling system
Capacity*
Fuel cell
stack 20.7 qt. (19.6 L, 17.2 Imp.qt.)
Inverter 5.0 qt. (4.7 L, 4.1 Imp.qt.)
Coolant
type
Fuel cell
stack“Toyota Genuine FC Stack Coolant”
• In order to safely cool the fuel cell stack,
which is at high voltages, the fuel cell stack
coolant is an exclusive high insulation prod-
uct.
• Never use water or other kinds of coolants as they will cause damage.
• Coolant changes are unnecessary.
• Do not reuse coolant that has been removed from the radiator.
• Coolant is colorless.
• Consult your Toyota dealer about replenish- ing or changing the fuel cell stack coolant.
Inverter Use either of the following:
• “Toyota Super Long Life Coolant”
• A similar high-quality ethylene glycol-based
non-silicate, non-amine, non-nitrite, and
non-borate coolant with long-life hybrid
organic acid technology
Do not use plain water alone.
NOTICE
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, imme-
diately contact your Toyota dealer.

515Alphabetical index
MIRAI_OM_USA_OM62073U
Child-protectors....................... 135
Cleaning ........................... 352, 356Aluminum wheels.................. 353
Exterior ................................. 352
Interior................................... 356
Seat belts .............................. 357
Clock ......................................... 328
Coat hooks ............................... 329
Condenser ................................ 371
Console box ............................. 321
Coolant Capacity ................................ 469
Checking ............................... 370
Preparing and checking Warning light ...................... 418
Cooling system ........................ 370 Fuel cell system
overheating......................... 457
Cruise control Dynamic radar cruise
control................................. 253
Cup holders.............................. 322
Curtain shield airbags ............... 37
Customizable features ............ 484 Daytime running light
system.................................... 203
Defogger Outside rear view mirrors ..... 309
Rear window ......................... 309
Windshield ............................ 309
Dimensions .............................. 466
Dinghy towing.......................... 185
Display Drive information .................. 118
Dynamic radar cruise control ................................ 253
Energy monitor ..................... 118
LDA (Lane Departure Alert with steering control) .......... 238
Multi-information display ....... 117
Parking Support Brake function
(for static objects) .............. 279
Warning message ................ 426
Do-it-yourself maintenance .... 364
Door courtesy lights Location ................................ 317
Wattage ................................ 471
Door lock Doors .................................... 132
Key ....................................... 449
Smart key system ................. 132
Wireless remote control ........ 132D
*: Refer to the “NAVIGATION SYSTEM OWNER’S MANUAL”.