TOYOTA MIRAI 2020 Owners Manual (in English)

3717-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62073U
7
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.

3727-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62073U■
Checking fluid level
The brake fluid level should be
between the “MAX” and “MIN”
lines on the tank.
“MAX”
“MIN”
■Adding fluid
Make sure to check the fluid ty pe and prepare the necessary ite m.
■Brake fluid can absorb moisture from the air
Excess moisture in the brake fluid can cause a dangerous loss o f braking effi-
ciency. Use only newly opened brake fluid.
Brake fluid
Fluid typeFMVSS No.116 DOT 3 or SAE J1703 brake fluid, or
FMVSS No.116 DOT 4 or SAE J1704 brake fluid
ItemClean funnel
WARNING
■ When filling the reservoir
Take care as brake fluid can harm your hands and eyes and damag e
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, see a doctor.
NOTICE
■ If the fluid level is low or high
It is normal for the brake fluid level to go down slightly as t he brake pads
wear out or when the fluid level in the accumulator is high.
If the reservoir needs frequent refilling, there may be a serio us problem.

3737-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62073U
7
Maintenance and care
If none of the washer do not work
or the warning message appears
on the multi-information display,
the washer tank may be empty.
Add washer fluid. (P. 426)
Washer fluid
WARNING
■When adding washer fluid
Do not add washer fluid when the fuel cell system is hot or ope rating, as
washer fluid contains alcohol and may catch fire if spilled on the fuel cell
system, etc.
NOTICE
■ Do not use any fluid ot her than washer fluid
Do not use soapy water or antifreeze instead of washer fluid.
Doing so may cause streaking on the vehicle’s painted surfaces, as well as
damaging the pump leading to problems of the washer fluid not s praying.
■ Diluting washer fluid
Dilute washer fluid with water as necessary.
Refer to the freezing temperatures listed on the label of the washer fluid bot-
tle.

3747-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62073U
12-volt batter y
The 12-volt battery is located in
the right-hand side of the trunk.
Remove the 12-volt battery cover.
Make sure that the 12-volt battery terminals are not corroded a nd that
there are no loose connections, cracks, or loose clamps.
Terminals
Hold-down clamp
Location
Removing the 12-volt battery cover
Exterior

3757-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62073U
7
Maintenance and care
Install the 12-volt battery cover.
■Before recharging
When recharging, the 12-volt battery produces hydrogen gas which is flam-
mable and explosive. Therefore, observe the following precautio ns before
recharging:
● If recharging with the 12-volt battery installed on the vehicle , be sure to dis-
connect the ground cable.
● Make sure the power switch on the charger is off when connectin g and dis-
connecting the charger cables to the 12-volt battery.
■ After recharging/reconnecting the 12-volt battery
●Unlocking the doors using the smart key system may not be possi ble imme-
diately after reconnecting the 12-volt battery. If this happens, use the wire-
less remote control or the mechanical key to lock/unlock the do ors.
● Start the fuel cell system with the power switch in ACCESSORY m ode. The
fuel cell system may not start with the power switch turned off. However, the
fuel cell system will operate normally from the second attempt.
● The power switch mode is recorded by the vehicle. If the 12-vol t battery is
reconnected, the vehicle will return the power switch mode to t he status it
was in before the 12-volt battery was disconnected. Make sure t o turn off
the power before disconnect the 12-volt battery. Take extra car e when con-
necting the 12-volt battery if the power switch mode prior to d ischarge is
unknown.
● 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 system will not start even after multiple attempts at al l methods above,
contact your Toyota dealer.
Installing the 12-volt battery cover

3767-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62073U
WARNING
■Chemicals in the 12-volt battery
The 12-volt battery contains poisonous and corrosive sulfuric a cid and may
produce hydrogen gas which is flammable and explosive. To reduce the risk
of death or serious injury, take the following precautions while working on or
near the 12-volt battery:
● Do not cause sparks by touching the 12-volt battery terminals w ith tools.
● Do not smoke or light a match near the 12-volt battery.
● Avoid contact with eyes, skin and clothes.
● Never inhale or swallow electrolyte.
● Wear protective safety glasses when working near the 12-volt ba ttery.
● Keep children away from the 12-volt battery.
■ Where to safely charge the 12-volt battery
Always charge the 12-volt battery in an open area. Do not charg e the
12-volt battery in a garage or closed room where there is insufficient ventila-
tion.
■ How to recharge the 12-volt battery
Only perform a slow charge (5 A or less). The 12-volt battery m ay explode if
charged at a quicker rate.
■ Emergency measures regarding electrolyte
● If electrolyte gets in your eyes
Flush your eyes with clean water for at least 15 minutes and ge t immedi-
ate medical attention. If possible, continue to apply water wit h a sponge or
cloth while traveling to the nearest medical facility.
● If electrolyte gets on your skin
Wash the affected area thoroughly. If you feel pain or burning, get medical
attention immediately.
● If electrolyte gets on your clothes
It can soak through clothing on to your skin. Immediately take off the cloth-
ing and follow the procedure above if necessary.
● If you accidentally swallow electrolyte
Drink a large quantity of water or milk. Get emergency medical attention
immediately.
■ When replacing the 12-volt battery
Use a 12-volt battery designed for this vehicle. Failure to do so may cause
gas (hydrogen) to enter the passenger compartment, causing a fire or
explosion.
For replacement of the 12-volt battery, contact your Toyota dea ler.

3777-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62073U
7
Maintenance and care
NOTICE
■When recharging th e 12-volt battery
Never recharge the 12-volt battery while the fuel cell system i s operating.
Also, be sure all accessories are turned off.

3787-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62073U
Tires
Check if the treadwear indicators are showing on the tires. Also check
the tires for uneven wear, such as excessive wear on one side o f the
tread.
Check the spare tire condition and pressure if not rotated.
New tread
Worn tread
Treadwear indicator
The location of treadwear indicators is shown by a “TWI” or “ ” mark,
etc., molded into the s idewall of each tire.
Replace the tires if the treadwear indicators are showing on a tire.
Rotate the tires in the order
shown.
To equalize tire wear and extend
tire life, Toyota recommends that
tire rotation is carried out at the
same interval as tire inspection.
Replace or rotate tires in accordance with maintenance sched-
ules and treadwear.
Checking tires
Tire rotation
Front

3797-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62073U
7
Maintenance and care
Your vehicle is equipped with a tire pressure warning system that uses
tire pressure warning valves and transmitters to detect low tire infla-
tion pressure before serious problems arise.
If the tire pressure drops below a predetermined level, the dri ver is
warned by a warning light. ( P. 421)
◆Installing tire pressure warn ing valves and transmitters
When replacing tires or wheels, tire pressure warning valves an d
transmitters must also be installed.
When new tire pressure warning valves and transmitters are
installed, new ID codes must be registered in the tire pressure
warning computer and the tire pressure warning system must be
initialized. Have tire pressure warning valves and transmitter ID
codes registered by your Toyota dealer. ( P. 379)
◆Registering ID codes
The tire pressure warning valve and transmitter is equipped wit h a
unique ID code. When replacing a tire pressure warning valve an d
transmitter, it is necessary to register the ID code. Have the ID code
registered by your Toyota dealer.
Tire pressure warning system

3807-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62073U
■When to replace your vehicle’s tires
Tires should be replaced if:
●The treadwear indicators are showing on a tire.
●You have tire damage such as cuts, splits, cracks deep enough t o
expose the fabric, and bulges indicating internal damage
●A tire goes flat repeatedly or c annot be properly repaired due to the size
or location of a cut or other damage
If you are not sure, consult with your Toyota dealer.
■Replacing tires and wheels
If the ID code of the tire press ure warning valve and transmitt er is not reg-
istered, the tire pressure warni ng system will not work properly. A f t e r d r i v -
ing for about 20 minutes, the tire pressure warning light blink s for 1
minute and stays on to indi cate a system malfunction.
■Tire life
Any tire over 6 years old must be checked by a qualified techni cian even
if it has seldom or never been u sed or damage is not obvious.
■Routine tire inflation pressure checks
The tire pressure warning system does not replace routine tire inflation
pressure checks. Make sure to chec k tire inflation pressure as part of
your routine of daily vehicle checks.
■Maximum load of tire
Check that the maximum load of t he replacement tire is greater than 1/2
of the Gross Axle Weight Ratings (GAWR) of either the front axl e or the
rear axle, whichever is greater.
For the GAWR, see the Certification
Label. For the maximum load of the tire,
see the load limit at maximum cold tire
inflation pressure mentioned on the
sidewall of the tire. ( P. 4 7 2 )