coolant TOYOTA MIRAI 2020 (in English) User Guide

3707-3. Do-it-yourself maintenance
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The coolant level is satisfactory if it is between the “FULL” a nd “LOW”
lines on the reservoir when the fuel cell system is cold.
“FULL” line
“LOW” line
If the level is on or below the
“LOW” line, contact your Toyota
dealer.
The coolant level is satisfact ory if it is between the “FULL” a nd “LOW”
lines on the reservoir when the fuel cell system is cold.
Inverter coolan t reservoir cap
“FULL” line
“LOW” line
If the level is on or below the
“LOW” line, add coolant up to the
“FULL” line.
■ 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-bora te coolant with
long-life hybrid organic acid technology.
For the U.S.A.: “Toyota Super Long Life Coolant” is a mixture o f 50% coolant and
50% deionized water. (Minimum temperature: -31
F [-35C])
For Canada: “Toyota Super Long Life Coolant” is a mixture of 55 % coolant and
45% deionized water. (Minimum temperature: -44
F [-42C])
For more details about inverter coolant, contact your Toyota dealer.
Fuel cell stack coolant
NOTICE
■ Fuel cell stack coolant
An exclusive coolant for the fuel cell system is filled in the fuel cell stack
coolant reservoir. Do not use any substitute. It may damage you r vehicle.
Inverter coolant

3717-3. Do-it-yourself maintenance
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Maintenance and care
■If the inverter coolant level drops within a short time of repl enishing
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 system.
Check the radiator and condenser and clear away any foreign objects.
If either of the above parts is extremely dirty or you are not sure of
their condition, have your vehic le inspected by your Toyota dea ler.
WARNING
■When the fuel cell system is hot
Do not remove the coolant reservoir caps.
The cooling system may be under pressure and may spray hot coolant if the
cap is removed, causing serious injuries, such as burns.
NOTICE
■When adding coolant
Coolant is neither plain water nor straight antifreeze. The cor rect 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 p arts or paint.
Radiator and condenser
WARNING
■When the fuel cell system is hot
Do not touch the radiator or condenser as they may be hot and c ause seri-
ous injuries, such as burns.

4178-2. Steps to take in an emergency
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When trouble arises
If you think something is wrong
●Fluid leaks un der the vehicle.
(Water dripping from the air conditioning a fter use is normal.)
● Flat-looking tires or uneven tire wear
● The high coolant temperature war ning light flashes or comes on
● Excessive tire squeal when cornering
● Strange noises related to the suspension system
● Pinging or other noises rel ated to the fuel cell system
● Stumbling or running roughly
● Appreciable loss of power
● Vehicle pulls heavily to one side when braking
● Vehicle pulls heavily to one s ide when driving on a level road
● Loss of brake effectiveness, spongy feeling, pedal almost touch es
the floor
If you notice any of the followi ng symptoms, your vehicle proba -
bly needs adjustment or repair. Contact your Toyota dealer as
soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms

4188-2. Steps to take in an emergency
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If a warning light turns on or a war ning
buzzer sounds
Calmly perform the following actions if any of the warning ligh ts
comes on or flashes. If a light comes on or flashes, but then
goes off, this does not necessarily indicate a malfunction in the
system. However, if this continues to occur, have the vehicle
inspected by your Toyota dealer.
Warning light and w arning buzzer list
Warning lightWarning light/Details/Actions
Hydrogen leak warning light (warning buzzer)
When a hydrogen gas leak is detected, a buzzer sounds,
a light comes on, and a warning message is displayed on
the multi-information display.
 P. 93
(U.S.A.)
(Red)
(Canada)
Brake system warning li ght (warning buzzer)*1
Indicates that:
• The brake fluid level is low; or
• The brake system is malfunctioning
 Immediately stop the vehicle in a safe place and con-
tact your Toyota dealer. Continuing to drive the vehi-
cle may be dangerous.
Charging system warning light
Indicates a malfunction in the vehicle’s charging system
 Immediately stop the vehicle in a safe place and con-
tact your Toyota dealer.
High coolant temperature warning light
Indicates that the coolant temperature is abnormal
P. 457
 Immediately stop the vehicle in a safe place and con-
tact your Toyota dealer.
(Yellow)
Brake system warning light
Indicates a malfunction in:
• The regenerative braking system; or
• The electronically controlled brake system
 Have the vehicle inspected by your Toyota dealer
immediately.

4578-2. Steps to take in an emergency
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When trouble arises
If your vehicle overheats
The following may indicate that your vehicle is overheating.
● The high coolant temperature warning light ( P. 418) 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. 426) 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

4588-2. Steps to take in an emergency
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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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4598-2. Steps to take in an emergency
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When trouble arises
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.4

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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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
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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.