2023 TOYOTA MIRAI radiator cap

4117-3. Do-it-yourself maintenance
Owners Manual_USA_M62064_en
7
Maintenance and care
Inverter coolant reservoir cap
“MAX” line
“MIN” line
If the level is on or below the “MIN”
line, add coolant up to the “MAX”
line. ( P.490)
■Inverter coolant selection
Only use “Toyota Super Long Life
Coolant” or a similar high quality
ethylene glycol based non-silicate,
non-amine, non-nitrite, and non-
borate coolant with long-life hybrid
organic acid technology.
U.S.A.:
“Toyota Super Long Life Coolant” is
a mixture of 50% coolant and 50%
deionized water. (Minimum tem-
perature: -31°F [-35°C])
Canada:
“Toyota Super Long Life Coolant” is
a mixture of 55% coolant and 45%
deionized water. (Minimum tem-
perature: -44°F [-42°C])
For more details about coolant, con-
tact your Toyota dealer.
■If the inverter coolant level
drops within a short time of
replenishing
Visually check the radiators, hoses,
inverter coolant reservoir cap, drain
cock and water pump.
If you cannot find a leak, have your
Toyota dealer test the cap and
check for leaks in the cooling sys- tem.
Check the radiator and con-
denser and clear away any for-
eign objects. If either of the
above parts is extremely dirty or
you are not sure of their condi-
tion, have your vehicle
inspected by your Toyota dealer.
WARNING
■When the cell system is hot
Do not remove the coolant reser-
voir caps. ( P.493)
The cooling system may be under
pressure and may spray hot cool-
ant if the cap is removed, causing
serious injuries, such as burns.
NOTICE
■When adding coolant
Coolant is neither plain water nor
straight antifreeze. The correct
mixture of water and antifreeze
must be used to provide proper
lubrication, corrosion protection
and cooling. Be sure to read the
antifreeze or coolant label.
■If you spill coolant
Be sure to wash it off with water to
prevent it from damaging parts or
paint.
Checking the radiator and
condenser
WARNING
■When the fuel cell system is
hot
Do not touch the radiator or con-
denser as they may be hot and
cause serious injuries, such as
burns.

4938-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
8
When trouble arises
able.
6 Start the fuel cell system and
turn the air conditioning sys-
tem on to check that the radi-
ator cooling fan operate and
to check for coolant leaks
from the radiator or hoses.
The fan operate when the air condi-
tioning system is turned on immedi-
ately after a cold s tart. Confirm that
the fan is operating by checking the
fan sound and air flow. If it is diffi-
cult to check these, turn the air con-
ditioning system on and off
repeatedly.
(The fan may not o perate in freez-
ing temperatures.)
7 If the fan is not operating:
Stop the fuel cell system
immediately and contact your
Toyota dealer.
If the fan is operating:
Have the vehicle inspected at
the nearest Toyota dealer.
WARNING
■When inspecting under the
hood of your vehicle
Observe the following precau-
tions.
Failure to do so may result in seri-
ous injury such as burns.
●If steam is seen coming from
under the hood, do not open the
hood until the steam has sub-
sided. The fuel cell unit com-
partment may be very hot.
●Even if fuel cell system has
stopped, the cooling fan may
begin to move suddenly.
Do not touch or approach the
rotating parts of the fan. Doing
so may lead to fingers, clothes
or tools getting caught, resulting
in injury.
●Do not loosen the coolant reser-
voir caps or radia tor cap, while
the fuel cell system and radiator
are hot.
High temperature steam or
coolant could spray out.
NOTICE
■When inverter coolant
Add coolant slowly after the fuel
cell system has cooled down suffi-
ciently. Adding inverter cool cool-
ant to a hot fuel cell system too
quickly can cause damage to the
fuel cell system.
■To prevent damage to the
cooling system
Observe the following precau-
tions:
●Avoid contaminating the coolant
with foreign matter (such as
sand or dust etc.).
●Do not use any coolant additive
with inverter coolant.
●For replacement of the fuel cell
stack coolant, contact your Toy-
ota dealer.
●Do not use water or any other
coolant when refilling the fuel
cell stack coolant. Also, do not
use any additive agents for the
coolant.

4999-1. Specifications
Owners Manual_USA_M62064_en
9
Vehicle specifications
*: The fluid capacity is a reference quantity. If replacement is necessary, contact your Toyota dealer.
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 product.
 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 deale r about replenishing
or changing the fuel cell stack coolant.
Inverter
Use either of the following:
 “Toyota Super Long Life Coolant”
 Similar high-quality ethylene glycol-based non-
silicate, non-amine, non- nitrite, and non-borate
coolant with long-life hybrid org anic acid tech-
nology
Do not use plain water alone.
NOTICE
■Fuel cell stack coolant
The fuel cell stack coolant is e xclusive for fuel cell stack usage. Damage
may occur when water or any other type of coolant is used, so n ever use
any other fluid.
If the fuel cell stack coolant is low, immediately contact your Toyota dealer.

552Alphabetical Index
Owners Manual_USA_M62064_en
Pre-Collision System (PCS)... 219 Enabling/disabling the system........................................... 222
Function ............................... 219
Warning light ........................ 456
R
Radar cruise control (dynamic radar cruise control with full-
speed range) ......................... 244
Radiator ................................... 411
RCD (Rear Camera Detection) ............................................... 277Enabling/disabling the system ........................................... 278
Warning message ................ 279
RCTA (Rear Cross Traffic Alert) ............................................... 272Enabling/disabling the system ........................................... 273
Warning lights....................... 458
Warning message ................ 273
Rear automatic air conditioning system ................................... 349
Rear Camera Detection (RCD) ............................................... 277Enabling/disabling the system ........................................... 278
Warning message ................ 279
Rear Cross Traffic Alert (RCTA) ............................................... 272Enabling/disabling the system ........................................... 273
Warning lights....................... 458
Warning message ................ 273
Rear door sunshades ............ 380
Rear footwell lights ................ 355
Rear seats Cleaning ............................... 396
Head restraints ..................... 145
Seat heaters ......................... 351
Seat ventilators .................... 351 Rear side marker lights
Light switch...........................198
Replacing light bulbs ............443
Rear sunshade ........................381
Rear turn signal lights............190 Replacing light bulbs ............443
Turn signal lever ...................190
Rear view mirror Digital Rear-view Mirror ........150
Inside rear view mirror ..........149
Outside rear view mirrors .....160
Rear window defogger ...335, 342
Refueling ............ .....................210
Capacity ...............................497
Fuel types .............................497
When the fuel door cannot be opened ...............................482
Regenerative braking ...............78 Warning lights .......................454
Replacing Electronic key battery ...........436
Fuses....................................438
Light bulbs ............................443
Tires......................................424
Road accident cautions ...........88
Road Sign Assist ....................241
Roof film ..................................393
RSA (Road Sign Assist) .........241
Running out of fuel...................83
S
Safety Connect .........................65
Seat belt reminder light..460, 461
Seat belt shoulder anchor height
Adjustment .............................32
Seat belts...................................29 Active Assist ...........................33
Adjusting the seat belt shoulder anchor height........................32
Automatic Locking Retractor (ALR) ....................................31