coolant TOYOTA MIRAI 2018 Owners Manual (in English)

832. Fuel cell vehicle
2
Fuel cell system
MIRAI_OM_USA_OM62025U
The fuel cell vehicle has high-voltage components (about 650 V m axi-
mum) such as a fuel cell stack, traction battery, power control unit,
high-voltage cables (which are di stinguished from low-voltage cables
by their orange covers), electric motor (traction motor), etc., and high-
temperature parts such as the radiator for cooling. Pay attenti on to all
warning labels attached to the vehicle.
This diagram is for illustrative purposes only and may differ f rom the
actual vehicle.
High-voltage and high-temperature components
Warning label
Power control unit
High-voltage cables (orange)
Fuel cell stack
Traction battery
Service plug
Fuel cell converter Electric motor (traction motor)
Air conditioning compressor
Radiator for inverter cooling
Radiator for fuel cell stack
cooling
Auxiliary inverter
Cabin coolant heater

872. Fuel cell vehicle
2
Fuel cell system
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Fuel cell stack coolant
●Fuel cell stack coolant uses a specifically-designed fluid with high electrical
insulation properties, in order to safely cool the high-voltage fuel cell stack.
● Never add water or other coolants to the fuel cell stack coolin g system, as
they will cause permanent damage.
● Consult your Toyota dealer for replenishing or changing the fue l cell stack
coolant.
■ Ion filter
●An ion filter is installed in the coolant lines for the fuel ce ll stack, in order to
maintain the normal insulation properties of the coolant.
● It is necessary to periodically change the ion filter. ( P. 378) Contact your
Toyota dealer for this periodic maintenance.
■ Tailpipe
●When the power switch is turned off and the fuel cell system is stopped
( P. 173) after driving, exhaust water is discharged. Be careful w hen stand-
ing behind the vehicle to avoid dripping or spraying.
● It is possible to manually purge the exhaust. This may be desirable, for
instance, before parking in a garage. This is done by pressing the H
2O
switch. ( P. 173)
● On cold days, water vapor in the exhaust may appear as a white mist emit-
ted from the tailpipe. This is not a malfunction.
● If the tailpipe is blocked, the fuel cell system will stop.
■ Hydrogen detectors
When the power switch is turned to ON mode, the hydrogen detect ors are
activated.

882. Fuel cell vehicle
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Power output restriction
When the power output is restricted, the vehicle may fail to accelerate or even
decelerate, even though the accelerator pedal is depressed. If a safe driving
speed cannot be maintained, stop the vehicle in a safe place aw ay from the
traffic. This may be caused by the following conditions:
● The coolant temperature may be too high. This can be caused by driving
conditions such as repeated sudden acceleration and deceleratio n, continu-
ous driving on an incline, continuous driving at high altitudes with a high
load, etc. In such situations, the power output restriction ind icator (amber) is
displayed on the main display, “High FC Temperature Reduced Power” is
displayed on the multi-information display, and the power outpu t is
restricted. Once the coolant returns to normal temperature, the power out-
put will return to normal. ( P. 377)
● The remaining fuel may be low. After the low fuel warning indicator comes
on, the output power will be gradually restricted in order to extend the possi-
ble driving distance. Once getting to this point, the remaining driving dis-
tance possible is short. Immediately refill the vehicle with hy drogen.
● On cold days, the low fuel warning indicator comes on faster than usual and
the output power is restricted.
■ Vehicle proximity notification system
In the following cases, the vehicle proximity notification syst em may be diffi-
cult to hear for people around.
● In very noisy areas
● In wind or rain
Also, because the vehicle proximity notification system is loca ted in the front
of the vehicle, it may be more difficult to hear from the rear of the vehicle
compared to the front.
■ Electromagnetic waves (EMF)
●High-voltage parts and cables in fuel cell vehicles have an ele ctromagnetic
shielding configuration, and therefore emit approximately the s ame amount
of electromagnetic waves as conventional gasoline-powered vehicles or
home electronic appliances.
● Your vehicle may cause sound interference in some third party-p roduced
radio parts.
■ Traction battery
The traction battery has a limited service life. The lifespan of the traction bat-
tery can change according to driving style and driving conditio ns.

993. Instrument cluster
3
Instrument cluster
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Warning lights inform the driver of malfunctions in the indicated vehi-
cle’s systems.
Warning lights
*1
Hydrogen leak warning
light ( P. 369)*1
Slip indicator ( P. 370)
*1
Brake system warning
light (P. 369)Parking brake warning
light (P. 371)
*1
Charging system
warning light ( P. 369)Open door warning light
(P. 371)
*1High coolant
temperature warning
light ( P. 369)Low fuel level warning
light (P. 371)
*1
Brake system warning
light (P. 369)Driver’s and front
passenger’s seat belt
reminder light ( P. 3 7 1 )
*1
SRS warning light
(P. 370)*1
Master warning light
(P. 371)
*1
ABS warning light
(P. 370)*1
Tire pressure warning
light ( P. 371)
*1
(Red/
Ye l l o w )
Electric power steering
system warning light
( P. 370)*3Brake Override System/
Drive-Start Control
warning light ( P. 372)
*1, 2
PCS warning light
(P. 370)

1033. Instrument cluster
3
Instrument cluster
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Power restriction indicator
Blue: The fuel cell system output power is restricted, because the
coolant temperature is low.
Amber: The fuel cell system output power is restricted, because the
coolant temperature is high.
Outside temperature
Displays the outside temperature within the range of -40°F (-40 °C)
to 122°F (50°C).
Low outside temperature indicator flashes when the ambient tem-
perature is 37°F (3°C) or lower.
Driving range distance
Displays the estimated maximum distance that can be driven with
the quantity of fuel remaining. • Displays the possible driving d istance computed from the fuel
consumption studied f rom the driving history and the current
remaining amount of fuel. The ac tual possible driving distance
may differ as fuel consumpti on changes, depending on driving
environment (weather, traffic, etc.) and conditions (sudden acc el-
eration, air conditioning, etc.).
• When only a small amount of fuel is added to the hydrogen tanks, the display may not be updated.
Speedometer
Displays the vehicle speed.
Odometer and trip meter
Odometer:
Displays the total distance the vehicle has been driven.
Trip meter:
Displays the distance the vehicl e has been driven since the met er
was last reset.
Trip meters “A” and “B” can be used to record and display diffe rent
distances independently.
Distance after start:
Displays the distance driven afte r the fuel cell system was started.
Blank:
A blank is displayed.

1063. Instrument cluster
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Outside temperature display
●In the following situations, the correct outside temperature ma y not be dis-
played, or the display may take longer than normal to change.
• When stopped, or driving at low speeds (less than 16 mph [25 k m/h])
• When the outside temperature has changed suddenly (at the entr ance/
exit of a garage, tunnel, etc.)
● When “--” or “E” is displayed, the system may be malfunctioning .
Take your vehicle to your Toyota dealer.
■ Liquid crystal display
Small spots or light spots may appear on the display. This phen omenon is
characteristic of liquid crystal displays, and there is no prob lem continuing to
use the display.
■ Customization
The meter display can be customized on the multi-information di splay.
(Customizable features: P. 439)
NOTICE
■To prevent damage to the fuel cell system and its components
This vehicle is equipped with high coolant temperature warning light
(  P. 369), instead of, coolant temperature gauge.
The fuel cell system may be overheating if the high coolant temperature
warning light flashes or comes on. In this case, immediately st op the
vehicle in a safe place, and che ck the fuel cell system after it has cooled
completely.

3157-2. Maintenance
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7
Maintenance and care
General maintenance
Listed below are the general maintenance items that should be
performed at the intervals specified in the “Owner’s Warranty
Information Booklet” or “Own er’s Manual Supplement/Sched-
uled Maintenance Guide”. It is recommended that any problem
you notice should be brought to the attention of your Toyota
dealer or qualified s ervice shop for advice.
Motor compartment
ItemsCheck points
Brake fluidIs the brake fluid at the correct
level? ( P. 326)
CoolantIs the coolant at the correct level?
(P. 324)
Radiator/condenser
The radiator and condenser should
be free from foreign objects.
(P. 325)
Washer fluidIs there sufficient washer fluid?
(P. 327)
Tr u nk
ItemsCheck points
12-volt battery Check the connections. (P. 328)

3187-3. Do-it-yourself maintenance
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Do-it-yourself ser vice precautions
If you perform maintenance by yourself, be sure to follow the
correct procedure as given in these sections.
ItemsParts and tools
12-volt battery
condition
(  P. 3 2 8 )•Grease
• Conventional wrench (for terminal clamp bolts)
Brake fluid level
( P. 3 2 6 )• FMVSS No.116 DOT 3 or SAE J1703 brake fluid
• Rag or paper towel
• Funnel (used only for adding brake fluid)
Inverter coolant
level ( P. 324)
• “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.
“Toyota Super Long Life Coolant” is pre-mixed with
50% coolant and 50% deionized water.
• Funnel (used only for adding coolant)
Fuses ( P. 355)• Fuse with same amperage rating as original
Light bulbs
( P. 3 5 8 )
Radiator and con-
denser (
P. 325)
Tire inflation
pressure
( P. 346)• Tire pressure gauge
• Compressed air source
Washer fluid
( P. 3 2 7 )• Water or washer fluid containing antifreeze (for win-
ter use)
• Funnel (used only for adding water or washer fluid)

3197-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62025U
7
Maintenance and care
WARNING
The motor compartment contains many mechanisms and fluids that may
move suddenly, become hot, or become electrically energized. To avoid death
or serious injury, observe the following precautions.
■ When working on the motor compartment
● Be careful not to touch the high-voltage parts or hydrogen-rela ted parts.
● Make sure that the “READY” indicator is off.
● Keep hands, clothing and tools away from the moving fans.
● Be careful not to touch the motor, inverter, radiator, etc., ri ght after driving
as they may be hot. Coolant and other fluids may also be hot.
● Do not leave anything that may burn easily, such as paper and r ags, in the
motor compartment.
● Do not smoke, cause sparks or expose an open flame to the 12-volt bat-
tery. 12-volt battery fumes are flammable.
● Be extremely cautious when working on the 12-volt battery. It c ontains poi-
sonous and corrosive sulfuric acid.
● Take care because brake fluid can harm your hands or eyes and d amage
painted surfaces. If fluid gets on your hands or in your eyes, flush the
affected area with clean water immediately.
If you still experience discomfort, consult a doctor.
● Never touch, disassemble, remove or replace the high-voltage parts,
cables and their connectors. It can cause severe burns or electric shock
that may result in death or serious injury.
■ When working near the electric cooling fans or radiator grille
Be sure the power switch is off.
With the power switch in ON mode, the electric cooling fans may automati-
cally start to run if the air conditioning is on and/or the coolant temperature
is high. ( P. 325)
■ Safety glasses
Wear safety glasses to prevent flying or falling material, flui d spray, etc.,
from getting in your eyes.
NOTICE
■ If you remove the air cleaner filter
Driving with the air cleaner filter removed may cause excessive motor wear
due to dirt in the air.

3237-3. Do-it-yourself maintenance
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7
Maintenance and care
Motor compartment
Washer fluid tank (P. 327)
Brake fluid reservoir ( P. 326)
Inverter coolant reservoir ( P. 324)
Fuse boxes ( P. 355)
Fuel cell stack coolant radiator
( P. 325) Inverter coolant radiator
( P. 325)
Condenser ( P. 325)
Electric cooling fans
Fuel cell stack coolant reser-
voir ( P. 324)
Fuel cell stack coolant sub
radiator ( P. 325)