2017 TOYOTA MIRAI hydrogen

872. Fuel cell vehicle
2
Fuel cell system
MIRAI_OM_USA_OM62023U■
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 cooling system, as
they will cause permanent damage.
● Consult your Toyota dealer for repleni shing or changing the fuel cell stack
coolant.
■ Ion filter
●An ion filter is installed in the coolant lines for the fuel cell 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 when 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 detectors are
activated.

882. Fuel cell vehicle
MIRAI_OM_USA_OM62023U■
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 away 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 deceleration, continu-
ous driving on an incline, continuous driving at high altitudes with a high
load, etc. In such situations, the power output restriction indicator (amber) is
displayed on the main display, “High FC Temperature Reduced Power” is
displayed on the multi-information display, and the power output 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 hydrogen.
● 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 system 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 located 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 electromagne\
tic
shielding configuration, and therefore emit approximately the same amount
of electromagnetic waves as conventional gasoline-powered vehicles or
home electronic appliances.
● Your vehicle may cause sound interference in some third party-produced
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 conditions.

892. Fuel cell vehicle
2
Fuel cell system
MIRAI_OM_USA_OM62023U■
Hydrogen Gas Characteristics
●Hydrogen gas ignites more easily than gasoline. However, it is lighter than
air and disperses quickly. So even if hydrogen were to leak from the system,
it would quickly dilute until it is no longer flammable.
● As with gasoline and natural gas, hydrogen gas is not dangerous if it is han-
dled properly. Thoroughly read and understand the characteristics shown in
the table below.
Hydrogen gas
LPG
(Liquid Petroleum Gas)
Gasoline
Normal stateGaseous
(Lighter than air)Gaseous
(Heavier than air)
Volatile liquid
(evaporates
easily)
(Heavier than air)
Ease of
ignitionEasier than
gasolineAt the same level
as gasoline—
Ease of
accumulation
• Disperses
upward and is
diluted to safe
concentrations
in open air
• Does not adhere to
clothing
• Spreads on the
ground or floor
• Does not adhere to
clothing• Spreads on theground or floor
• Adheres to clothing
Detectability
•Due to itscolorless and
odorless state,
difficult to detect
by sight or smell
• Vehicle
hydrogen
detectors will
display a
warning on the
multi-
information
display
• Detectable by odor and gas
leaking noise• Detectable bycolor and odor

902. Fuel cell vehicle
MIRAI_OM_USA_OM62023U■
Basic concepts of hydrogen safety
●Prevent leakage
The pipe joints of the hydrogen pipelines are designed to prevent leaks.
The joints are checked for gas leakage at every official vehicle inspection.
● Detect to stop leakage
• The vehicle is equipped with hydrogen detectors. If the hydrogen detec-
tors detect a leak, the hydrogen tank valves automatically close to pre-
vent more hydrogen from escaping.
• The vehicle is equipped with a collision sensor. If the collision sensor
detects a collision, the hydrogen tank valves automatically close to pre-
vent hydrogen gas from leaking from any damaged components.
● Disperse the leaked hydrogen gas
The hydrogen tanks and pipelines are located outside of the passenger
compartment, so any leaked gas will disperse into the atmosphere by
design.
● Eliminate sources of fire
No source of fire is located near the hydrogen pipelines by design.
WARNING
■Hydrogen-related components
● Never alter, customize, or disassemble any hydrogen-related parts.
● The hydrogen tanks, fuel cell stack, hydrogen pipelines, and connecting
components are filled with hydrogen gas. Do not remove or disassemble
these parts. Doing so can cause a hydrogen gas leak, resulting in fire or
explosion of the vehicle, which may result in death or serious injury.
■ When hydrogen gas leak or other malfunction is detected
● If you notice gas leaking noises or any other malfunction, immediately stop
the vehicle in a safe, well-ventilated place.
● If a warning message is shown on the multi-information display, immedi-
ately stop the vehicle in a safe, well-ventilated place.
● If a large amount of hydrogen gas leaking is noticed, turn off the power
switch, exit the vehicle, and stay far away from it. Display warning signs
and keep sources of fire away from the vehicle. If possible, get assistance.
When the above is done, immediately contact your Toyota dealer.

922. Fuel cell vehicle
MIRAI_OM_USA_OM62023U
WARNING
■Precautions in case of an accident
In the event of an accident, observe the following precautions. Failure to do
so can cause fire or electric shocks, resulting in death or serious injury.
● Stop the vehicle in a safe place to prevent subsequent accidents. Shift the
shift position to P and apply the parking brake.
● Check for hydrogen gas leakage.
Hydrogen leaks will cause a warning message to be shown on the multi-
information display. Larger leaks may also be audible.
● If a large amount of hydrogen gas leaking is noticed, turn off the power
switch, exit the vehicle, and stay far away from it. Display warning signs
and keep sources of fire away from the vehicle. If possible, get assistance.
When the above is done, immediately contact your Toyota dealer.
● Do not touch the high-voltage parts, cables (orange), or connectors.
● If electric wires are exposed inside or outside your vehicle, an electric
shock may occur. Never touch exposed electric wires.
● If a fluid leak occurs, do not touch the fluid as it may be the strong alkaline
electrolyte from the traction battery. If it comes into contact with your skin
or eyes, wash it off immediately with a large amount of water, and seek
immediate medical attention.
● If a vehicle fire occurs, extinguish it with a Class A, B, or C fire extin-
guisher. If using water, apply a large amount from a hydrant.
● In case of a vehicle fire, the hydrogen gas in the hydrogen tanks is
released via the hydrogen tank valves toward the rear of the vehicle
angled downward, in order to reduce the damage to the hydrogen tanks.
Keep away from the vehicle.
● If your vehicle needs to be towed, do so with the front wheels lifted. If the
wheels are touching the ground, the electric motor (traction motor) may
continue to generate electricity. This may cause a fire.

993. Instrument cluster
3
Instrument cluster
MIRAI_OM_USA_OM62023U
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)

1023. Instrument cluster
MIRAI_OM_USA_OM62023U
Gauges and meters
Main display
Displays the speedometer, fuel gauge, etc. (→P. 102)
Multi-information display
Presents the driver with a variety of vehicle data.
Displays warning messages in case of a malfunction. ( →P. 376)
Shift position indicator
Displays the selected shift position. (→P. 179)
Clock
→P. 280
Fuel gauge
Displays the quantity of fuel
remaining in the hydrogen
tanks.
Main display

1033. Instrument cluster
3
Instrument cluster
MIRAI_OM_USA_OM62023U
ECO MODE indicator and POWER MODE indicator
Displays the selected driving mode.
(→P. 181)
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. • This distance is computed base d on your average fuel consump-
tion. As a result, the actual dist ance that can be driven may differ
from that displayed.
• 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 meter
was last reset.
Trip meters “A” and “B” can be used to record and display different
distances independently.
Distance after start:
Displays the distance driven after the fuel cell system was started.
Blank:
A blank is displayed.