TOYOTA MIRAI 2018 Owners Manual (in English)

4018-2. Steps to take in an emergency
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8
When trouble arises
If the 12-volt batter y is discharged
If you have a set of jumper (or booster) cables and a second vehicle
with a 12-volt battery, you can jump start your vehicle by foll owing the
steps below.
Confirm that the electronic key
is being carried.
When connecting the jumper (or
booster) cables, depending on the
situation, the alarm may activate
and the doors may lock. ( P.##)
Open the hood (P. 320) and
fuse box cover.
Open the exclusive jump start-
ing terminal cover.
The following procedures may be u sed to start the fuel cell sys-
tem if the 12-volt battery is discharged.
You can also call your Toyota de aler or a qualified repair shop.

4028-2. Steps to take in an emergency
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Remove the motor cover.
Connect the jumper cables according to the following procedure:Connect a positive jumper cable clamp to the exclusive jump
starting terminal on your vehicle.
Connect the clamp on the other end of the positive cable to the
positive (+) battery termi nal on the second vehicle.
Connect a negative cable clamp to the negative (-) battery term i-
nal on the s econd vehicle.
Connect the clamp at the other e nd of the negative cable to a
solid, stationary, unpainted meta llic point away from the exclusive
jump starting terminal and any moving parts, as shown in the
illustration.
Start the engine of the second v ehicle. Increase the engine speed
slightly and maintain at that lev el for approximately 5 minutes to
recharge the 12-volt battery of your vehicle.
Maintain the engine speed of the second vehicle and start the f uel
cell system of your vehicle by tu rning the power switch to ON mode.

4038-2. Steps to take in an emergency
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When trouble arises
Make sure the “READY” indicator comes on. If the indicator does
not come on, contact your Toyota dealer.
Once the fuel cell system has started, remove the jumper cables in
the exact reverse order from which they were connected.
Close the exclusive jump starting terminal cover, reinstall the motor
cover and the fuse box cover to its original position.
Once the fuel cell system starts, have the vehicle inspected at your
Toyota dealer as soon as possible.
■ Starting the fuel cell system when the 12-volt battery is discharged
The fuel cell system cannot be started by push-starting.
■ To prevent 12-volt battery discharge
●Turn off the headlights and the audio system while the fuel cell system is off.
● Turn off any unnecessary electrical components when the vehicle is running
at a low speed for an extended period, such as in heavy traffic .
■ Charging the 12-volt battery
The electricity stored in the 12-volt battery will discharge gr adually even when
the vehicle is not in use, due to natural discharge and the dra ining effects of
certain electrical appliances. If the vehicle is left for a lon g time, the 12-volt
battery may discharge, and the fuel cell system may be unable to start. (The
12-volt battery recharges automatically while the fuel cell sys tem is operat-
ing.)
■ When the 12-volt battery is removed or discharged
● In some cases, it may not be possible to unlock the doors using the smart
key system when the 12-volt battery is discharged. Use the wire less remote
control or the mechanical key to lock or unlock the doors.
● The fuel cell system may not start on the first attempt after t he 12-volt bat-
tery has recharged but will start normally after the second att empt. This is
not a malfunction.
● The power switch mode is memorized by the vehicle. When the 12- volt bat-
tery is reconnected, the system will return to the mode it was in before the
12-volt battery was discharged. Before disconnecting the 12-volt battery,
turn the power switch off.
If you are unsure what mode the power switch was in before the 12-volt bat-
tery discharged, be especially careful when reconnecting the 12 -volt battery.
● If the 12-volt battery is depleted with the shift position in P , it will not be pos-
sible to shift the shift position other than P. In this case, the vehicle cannot
be towed without lifting both front wheels because the front wheels are
locked by the parking lock. ( P. 363)

4048-2. Steps to take in an emergency
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When the 12-volt battery is reconnected, start the fuel cell sy stem, depress
the brake pedal, and confirm that it is possible to shift into each shift posi-
tion.
● If the battery is removed or the terminals disconnected without operating the
water release function during cold weather, the vehicle may not start due to
the fuel cell system being frozen. To prevent this, operate the water release
function before removing the battery or disconnecting the termi nals.
( P. 176)
■ When exchanging the 12-volt battery
Use a Central Degassing type 12-volt battery (Japanese Industri al Stan-
dards). Also, use 12-volt batteries with case sizes similar to one prior the
exchange and an equivalent 20 hour rate capacity (20HR) or grea ter.
• If the sizes differ, the 12-volt battery cannot be properly se cured.
• If the 20 hour rate capacity is low, even if the time period w here the vehicle
is not used is a short time, the 12-volt battery may discharge and fuel cell
system may not be able to start.
For details, consult your Toyota dealer.
WARNING
■ Avoiding 12-volt batte ry fires or explosions
Observe the following precautions to prevent accidentally ignit ing the flam-
mable gas that may be emitted from the 12-volt battery:
● Make sure each jumper cable is connected to the correct terminal and that
it is not unintentionally in contact with any other than the in tended terminal.
● Do not allow the other end of the jumper cable connected to the “+” termi-
nal to come into contact with any other parts or metal surfaces in the area,
such as brackets or unpainted metal.
● Do not allow the + and - clamps of the jumper cables to come in to contact
with each other.
● Do not smoke, use matches, cigarette lighters or allow open fla me near
the 12-volt battery.

4058-2. Steps to take in an emergency
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When trouble arises
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. 330
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.

4068-2. Steps to take in an emergency
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If your vehicle overheats
The following may indicate that your vehicle is overheating.
● The high coolant temperature warning light ( P. 369) comes on
or flashes, or a loss of fuel ce ll system power is experienced. (For
example, the vehicle s peed does not increase.)
● “FC System Overheat Output Power is Limited” ( P. 376) is dis-
played on the multi-in formation display
● Steam comes out from under the hood.
Label
Fuel cell stack coolant
reservoir Inverter coolant reservoir

4078-2. Steps to take in an emergency
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When trouble arises
■If the high coolant temperature warning light comes on or
flashes
Stop the vehicle in a safe place and turn off the air conditioning 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.

4088-2. Steps to take in an emergency
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The fuel cell stack coolant level
is satisfactory if it is between
the “FULL” and “LOW” lines on
the reservoir.
Fuel cell stack coolant reser-
voir
“FULL” line
“LOW” line
If the amount of fuel cell stack coolant is low:
Immediately contact your Toyota dealer.
If the amount of fuel cell st ack coolant is not low:
Have the vehicle inspected at the neare st Toyota dealer.
Even if the fuel cell stack cool-
ant is low, do not refill it.

4098-2. Steps to take in an emergency
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When trouble arises
■If “FC System Overheat Output Power 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.

4108-2. Steps to take in an emergency
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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.