2017 TOYOTA MIRAI battery

3297-3. Do-it-yourself maintenance
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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 precautions 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 connecting and dis-
connecting the charger cables to the 12-volt battery.
■ After recharging/reconnect ing the 12-volt battery
● Unlocking the doors using the smart key system may not be possible 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 doors.
● Start the fuel cell system with the power switch in ACCESSORY mode. 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-volt battery is
reconnected, the vehicle will return the power switch mode to the status it
was in before the 12-volt battery was disconnected. Make sure to turn off
the power before disconnect the 12-volt battery. Take extra care when con-
necting the 12-volt battery if the power switch mode prior to discharge is
unknown.
● When the 12-volt battery is reconnected, start the fuel cell system, 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 all methods above,
contact your Toyota dealer.
Installing the 12-volt battery cover

3307-3. Do-it-yourself maintenance
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WARNING
■Chemicals in the 12-volt battery
The 12-volt battery contains poisonous and corrosive sulfuric acid 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 with 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 battery.
● 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 charge the 12-
volt battery in a garage or closed room where there is insufficient ventila-
tion.
■ How to recharge th e 12-volt battery
Only perform a slow charge (5 A or less). The 12-volt battery may 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 get immedi-
ate medical attention. If possible, continue to apply water with 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 dealer.

3317-3. Do-it-yourself maintenance
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Maintenance and care
NOTICE
■When recharging the 12-volt battery
Never recharge the 12-volt battery while the fuel cell system is operating.
Also, be sure all accessories are turned off.

3537-3. Do-it-yourself maintenance
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Maintenance and care
Electronic key battery
●Flathead screwdriver
● Small flathead screwdriver
● Lithium battery CR2032
Take out the mechanical key.
(→ P. 1 1 7 )
Remove the cover.
To prevent damage to the key,
cover the tip of the flathead screw-
driver with a rag.
Remove the depleted battery.
Insert a new battery with the “+”
terminal facing up.
Replace the battery with a new one if it is depleted.
You will need the following items:
Replacing the battery
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3547-3. Do-it-yourself maintenance
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■Use a CR2032 lithium battery
●Batteries can be purchased at your Toyota dealer, local electrical appliance
shops or camera stores.
● Replace only with the same or equivalent type recommended by the manu-
facturer.
● Dispose of used batteries according to local laws.
■ If the electronic key battery is depleted
The following symptoms may occur:
●The smart key system and wireless remote control will not function properly.
● The operational range will be reduced.
WARNING
■ Removed battery and other parts
These parts are small and if swallowed by a child, they can cause choking.
Keep away from children. Failure to do so could result in death or serious
injury.
NOTICE
■For normal operation after replacing the battery
Observe the following precautions to prevent accidents:
● Always work with dry hands.
Moisture may cause the battery to rust.
● Do not touch or move any other component inside the remote control.
● Do not bend either of the battery terminals.

359
8When trouble arises
MIRAI_OM_USA_OM62023U8-1. Essential information
Emergency flashers .......... 360
If your vehicle has to be stopped in an
emergency ...................... 361
8-2. Steps to take in an emergency
If your vehicle needs to be towed ......................... 362
If you think something is wrong .............................. 368
If a warning light turns on or a warning buzzer
sounds ............................ 369
If a warning message is displayed......................... 376
If you have a flat tire.......... 381
If the fuel cell system will not start ..................... 396
If the electronic key does not operate properly........ 398
If the 12-volt battery is discharged ................... 401
If your vehicle overheats ........................ 406
If the vehicle becomes stuck ............................... 412

3628-2. Steps to take in an emergency
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If your vehicle needs to be towed
In the following situations, it is not possible to be towed by another
vehicle using cables or chains, as the front wheels may be locked due
to the parking lock. Contact your Toyota dealer or commercial towing
service.
●There is a malfunction in the shift control system. ( →P. 378)
● There is a malfunction in the immobilizer system. ( →P. 72)
● There is a malfunction in the smart key system. ( →P. 398)
● The 12-volt battery is discharged. ( →P. 401)
If towing is necessary, we re commend having your vehicle
towed by your Toyota dealer or commercial towing service,
using a wheel-lift type truck or flatbed truck.
Use a safety chain system for all towing, and abide by all state/
provincial and local laws.
Situations when it is not possibl e to be towed by another vehicle

3738-2. Steps to take in an emergency
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When trouble arises
■SRS warning light
This warning light system monitors the airbag sensor assembly, front impact
sensors, side impact sensors (front door), side impact sensors (front), side
impact sensors (rear), driver’s seat posit ion sensor, driver’s seat belt buckle
switch, front passenger occupant classification system (ECU and sensors),
“AIR BAG ON” indicator light, “AIR BAG OFF” indicator light, front passen-
ger’s seat belt buckle switch, seat belt pretensioners, airbags, interconnect-
ing wiring and power sources. ( →P. 38)
■ Front passenger detection sensor, seat belt reminder and warning
buzzer
● If luggage is placed on the front passenger seat, the front passenger de\
tec-
tion sensor may cause the warning light to flash and the warning buzzer to
sound even if a passenger is not sitting in the seat.
● If a cushion is placed on the seat, the sensor may not detect a passenger,
and the warning light may not operate properly.
■ Electric power steering system warning light (warning buzzer)
When the 12-volt battery charge becomes insufficient or the voltage tempo-
rarily drops, the electric power steer ing system warning light may come on
and the warning buzzer may sound.
■
When the tire pressure warning light comes on
Inspect the appearance of the tire to check that the tire is not punctured.
If the tire is punctured: → P. 381
If the tire is not punctured:
After turning the power switch to off, turn it to ON mode again and make
sure the tire pressure warning light comes on or blinks.
The tire pressure warning light comes on
After the temperature of the tires have lowered sufficiently, check the
tire inflation pressure and adjust it to the specified level.
If the warning light does not go out even after several minutes, check
that the tire inflation pressu re is at the specified level.
If the warning light does not go out even after several minutes, have the
vehicle inspected by your Toyota dealer immediately.
The tire pressure warning light is blinking for 1 minute, and then comes
on
Malfunction in the tire pressure warning system. Have the system
checked by your Toyota dealer immediately.
■The tire pressure warning light may come on due to natural causes
The tire pressure warning light may come on due to natural causes such
as natural air leaks and tire inflat ion pressure changes caused by tem-
perature. In this case, adjusting the ti re inflation pressure will turn off the
warning light (afte r a few minutes).
■Conditions that the tire pressure warning system may not function
properly
→ P. 3 3 6
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