2017 TOYOTA MIRAI key battery

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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2
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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

3968-2. Steps to take in an emergency
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If the fuel cell system will not start
One of the following may be the cause of the problem:
●The electronic key may not be functioning properly. ( →P. 398)
● There may not be sufficient fuel in the vehicle’s tank.
Refuel the vehicle.
● The fuel door may be open. ( →P. 201)
● There may be a malfunction in the immobilizer system.
( → P. 72)
● There may be a malfunction in the shift control system.
* (→ P. 378)
● The fuel cell system may be malf unctioning due to an electrical
problem such as electronic key ba ttery depletion or a blown fuse.
However, depending on the type of malfunction, an interim mea-
sure is available to start the fuel cell system. ( →P. 177, 397)
● The electronic key may be in battery-saving mode. ( →P. 133)
*: It may not be possible to shift the shift position from P to another position.
One of the following may be the cause of the problem:
● The 12-volt battery may be discharged. ( →P. 401)
● The 12-volt battery terminal connections may be loose or corroded.
(→ P. 328)
Reasons for the fuel cell system not starting vary depending on
the situation. Check the follo wing and perform the appropriate
procedure:
The fuel cell system will not start even though the correct start-
ing procedure is being followed. ( →P. 172)
The interior lights and headlights are dim, or the horn does not
sound or sounds at a low volume.

3988-2. Steps to take in an emergency
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If the electronic key does not operate
properly
■Doors
Use the mechanical key
(→ P. 117) in order to perform
the following operations
(driver’s door only):
Locks all doors
Unlocks the door
Turning the key rearward
unlocks the driver’s door. Turn-
ing the key once again unlocks
the other doors.
■
Tr u n k
Turn the mechanical key clock-
wise to open.
If communication between the electronic key and vehicle is
interrupted ( →P. 134) or the electronic key cannot be used
because the battery is depleted, the smart key system and wire-
less remote control cannot be used. In such cases, the doors
can be opened and the fuel cell system can be started by follow-
ing the procedure below.
Locking and unlocking the doors

4008-2. Steps to take in an emergency
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■Stopping the fuel cell system
Shift the shift position to P and press the power switch as you normally do
when stopping the fuel cell system.
■ Replacing the key battery
As the above procedure is a temporary measure, it is recommended that the
electronic key battery be replaced immediately when the battery is depleted.
(→P. 353)
■ Alarm
Using the mechanical key to lock the doors will not set the alarm system.
If a door is unlocked using the mechanical key when the alarm system is set,
the alarm may be triggered. ( →P. 75)
■ When the electronic key does not work properly
●Make sure that the smart key system has not been deactivated in the cus-
tomization setting. If it is off, turn the function on.
(Customizable features →P. 436)
● Check if battery-saving mode is set. If it is set, cancel the function.
(→P. 133)
■ Changing power switch modes
Release the brake pedal and press the power switch in step above.
The fuel cell system does not start and modes will be changed each time the
switch is pressed. (→P. 174)
WARNING
■ When using the mechanical key and operating the power windows
Operate the power window after checking to make sure that there is no pos-
sibility of any passenger having any of their body parts caught in the win-
dow.
Also, do not allow children to operate the mechanical key. It is possible for
children and other passengers to get caught in the power window.
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4038-2. Steps to take in an emergency
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When trouble arises
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 gradually even when
the vehicle is not in use, due to natural discharge and the draining effects of
certain electrical appliances. If the vehicle is left for a long 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 system 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 wireless remote
control or the mechanical key to lock or unlock the doors.
● The fuel cell system may not start on the first attempt after the 12-volt bat-
tery has recharged but will start normally after the second attempt. 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)
● 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.
● Make sure that the key is not inside the vehicle when recharging or replac-
ing the 12-volt battery. The key may be locked in the vehicle if the alarm is
activated. ( →P. 75)
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