ECU TOYOTA MIRAI 2023 Repair Manual

4618-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
8
When trouble arises
■Rear passengers’ seat belt reminder lights (warning buzzer)*
*: Rear passengers’ seat belt warning buzzer:
The rear passengers’ seat belt war ning buzzer sounds to alert the rear
passenger that his or her seat belt is not fastened. If the sea t belt is
unfastened, the buzzer sounds int ermittently for a certain period of time,
after the seat belt is fastened and unfastened and the vehicle reaches a
certain speed.
■Warning buzzer
In some cases, the buzzer may not
be heard due to being in a noisy
location or audio sound.
■Front passenger detection sen-
sor, seat belt reminder and
warning buzzer
●If luggage is placed on the front
passenger seat, the front passen-
ger detection 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 n ot detect a pas-
senger, and the warning light may
not operate properly.
■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 position sensor,
driver’s seat belt buckle switch, front
passenger occupant classification
system (ECU and sensors), “AIR-
BAG ON” indicator light, “AIRBAG
OFF” indicator light, front passen-
ger’s seat belt buc kle switch, seat
belt pretensioners, airbags, inter-
connecting wiring and power
sources. ( P. 3 4 )
■Electric power steering system
warning light (warning buzzer)
When the 12-volt battery charge
becomes insufficient or the voltage
temporarily drops, the electric power
steering system warning light may
come on and the warning buzzer
may sound.
■When the tire pressure warning
light comes on
Inspect the tires to check if a tire is
punctured.
If a tire is punctured: P. 4 6 7
If none of the tires are punctured:
Turn the power switch off then turn it
to ON. Check if th e tire pressure
warning light com es on or blinks.
If the tire pressure warning light
blinks for approximately 1 minute
then stays on
There may be a malfunction in the
tire pressure warning system. Have
the vehicle inspected by your Toyota
dealer immediately.
If the tire pressur e warning light
comes on
1 After the temperature of the tires
has lowered sufficiently, check
the inflation pressure of each tire
and adjust them to the specified
level.
2 If the warning light does not turn
off even after several minutes
have elapsed, check that the
inflation pressure of each tire is
Warning lightDetails/Actions
Warns the rear passengers to fasten their seat belts
 Fasten the seat belt.

4668-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
■If a message that indicates the
need for visiting your Toyota
dealer is displayed
The system or part shown on the
multi-information display is malfunc-
tioning. Have the vehicle inspected
by your Toyota dealer immediately.
■If a message that indicates the
need for referring to Owner’s
Manual is displayed
●If any of the following messages
are shown on the multi-informa-
tion display, it may indicate a mal-
function. Have the vehicle
inspected by you r Toyota dealer
immediately.
• “Smart Key System Malfunction
See Owner’s Manual”
• “P Switch Malfunction Apply Park- ing Brake Securely When Parking
See Owner’s Manual”
• “Shift System Malfunction Apply Parking Brake Securely When
Parking See Owner’s Manual”
• “Shift System Unavailable Apply Parking Brake Securely When
Parking See Owner’s Manual”
• “Shift System Malfunction See Owner’s Manual”
• “Shift System Malfunction Stop in a Safe Place See Owner’s Man-
ual”
• “Battery Low Shifting Unavailable See Owner’s Manual”
• “FCV system malfunction”
• “Traction battery system malfunc-
tion”
• “Accelerator System Malfunction”
●If any of the following messages
are shown on the multi-informa-
tion display, it may indicate a mal-
function. Immediat ely stop the
vehicle and contact your Toyota
dealer.
• “Braking Power Low Stop in a Safe Place See Owner’s Manual”
• “FCV System Shutdown Due to
Hydrogen Leakage Stop in a Safe
Place See Owner’s Manual”
●If “FCV system stopped” is shown
on the multi-information display,
the vehicle may have run out of fuel. Stop the vehicle in a safe
place and, if the fuel level is low,
refuel the vehicle. (
P.83)
●If “Low Auxiliary Battery See
Owner’s Manual” is shown,
• When the display goes off after several seconds (displays for
about 6 seconds): Maintain the
fuel cell system operation for more
than 15 minutes and charge the
12-volt battery.
• When the display does not go off: Start up the fuel cell system using
the procedures: P. 4 8 5
●If “Maintenance Required for Trac-
tion Battery Cooling Parts See
Owner’s Manual” is shown, the fil-
ters may be clogged, the air intake
vents may be blocked, or there
may be a gap in the duct. There-
fore, perform the following correc-
tion procedure.
• Cleaning the traction battery air intake vents ( P.433)
If the warning message is shown
even if the vents are cleaned,
have the vehicle inspected by
your Toyota dealer.
■If “Ion Filter Maintenance
Required Visit Your Dealer” is
displayed
Ion filter replacement is necessary.
Contact your Toyota dealer.
NOTICE
■If “Low Auxiliary Battery See
Owner’s Manual” is displayed
frequently
The 12-volt battery may have
deteriorated. As the battery may
discharge in this state when left
unattended, have the battery
inspected by you r Toyota dealer.

4738-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
8
When trouble arises
wise as far as possible.
5 Make sure that the compres-
sor switch is off.
6 Lift the rubber stopper on the
compressor. 7
Remove the power plug from
the compressor.
8 Connect the power plug to
the power outlet socket.
( P.372)
9 Connect the bottle to the
compressor.
As shown in the illustration, insert
the bottle securely into the com-
pressor until the upper side of the
mark on the bottle is aligned with

4788-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
■When fixing the flat tire
●Stop your vehicle in a safe and
flat area.
●Do not touch the wheels or the
area around the brakes immedi-
ately after the vehicle has been
driven.
After the vehicle has been
driven, the wheels and the area
around the brakes may be
extremely hot. Touching these
areas with hands, feet or other
body parts may result in burns.
●Connect the valve and hose
securely with the tire installed
on the vehicle. If the hose is not
properly connected to the valve,
air leakage may occur as seal-
ant may be sprayed out.
●If the hose comes off the valve
while inflating the tire, there is a
risk that the hose will move
abruptly due to air pressure.
●After inflation of the tire has
completed, the sealant may
splatter when the hose is dis-
connected or some air is let out
of the tire.
●Follow the operation procedure
to repair the tire. If the proce-
dures not followed, the sealant
may spray out.
●Keep back from the tire while it
is being repaired, as there is a
chance of it bursting while the
repair operation is being per-
formed. If you notice any cracks
or deformation of the tire, turn
off the compressor switch and
stop the repair operation imme-
diately.
●The repair kit may overheat if
operated for a long period of
time. Do not operate the repair
kit continuously for more than
40 minutes.
●Parts of the re pair kit become
hot during operation. Be careful
handling the repair kit during
and after operation. Do not
touch the metal part connecting
the bottle and the compressor. It
will be extremely hot.
●Do not attach the vehicle speed
warning sticker to an area other
than the one indicated. If the
sticker is attached to an area
where an SRS airbag is located,
such as the pad of the steering
wheel, it may prevent the SRS
airbag from operating properly.
■Driving to spread the liquid
sealant evenly
Observe the following precautions
to reduce the risk of accidents.
Failing to do so may result in a
loss of vehicle control and cause
death or serious injury.
●Drive the vehicle carefully at a
low speed. Be especially careful
when turning and cornering.
●If the vehicle does not drive
straight or you feel a pull
through the steering wheel, stop
the vehicle and check the fol-
lowing.
WARNING

4878-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
8
When trouble arises
■Starting the fuel cell system
when the 12-volt battery is dis-
charged
The fuel cell system cannot be
started by push-starting.
■To prevent 12-volt battery dis-
charge
●Turn off the headlights and the
audio system while the fuel cell
system is off.
●Turn off any unnecessary electri-
cal components when the vehicle
is running at a low speed for an
extended period, such as in heavy
traffic.
■When the 12-volt battery is
removed or discharged
●Information stor ed in the ECU is
cleared. When the 12-volt battery
is depleted, have the vehicle
inspected at you r Toyota dealer.
●Some systems may require initial-
ization. ( P.526)
●If the 12-volt battery discharges, it
may not be possible to shift the
shift position to other positions.
In this case, the vehicle cannot be
towed without lifting both rear
wheels because the rear wheels will
be locked.
■When removing the 12-volt bat-
tery terminals
When the 12-volt battery terminals
are removed, the information stored
in the ECU is cleared. Before
removing the 12-volt battery termi-
nals, contact your Toyota dealer.
■Charging the 1 2-volt battery
The electricity stor ed in the 12-volt
battery will discharge gradually even
when the vehicle is not in use, due
to natural discharge and the drain-
ing effects of certain electrical appli-
ances. If the vehicle is left for a long
time, the 12-volt battery may dis-
charge, and the fuel cell system
may be unable to s tart. (The 12-volt battery recharges automatically
while the fuel cell
system is operat-
ing.)
■When recharging or replacing
the 12-volt battery
●In some cases, it may not be pos-
sible to unlock the doors using the
smart key system when the 12-
volt battery is discharged. Use the
wireless remote c ontrol 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 battery has recharged but will
start normally after the second
attempt. This is not a malfunction.
●The power switch mode is memo-
rized by the vehicle. When the 12-
volt battery is reconnected, the
system will return to the mode it
was in before the 12-volt battery
was discharged. Before discon-
necting the 12-volt battery, turn
the power switch off.
If you are unsure what mode the
power switch was in before the
12-volt battery discharged, be
especially careful when recon-
necting the 12-volt battery.
●When the 12-volt battery is recon-
nected, start the fuel cell system,
depress the brake pedal, and con-
firm that it is possible to shift into
each shift position.
●If the battery is removed or the ter-
minals disconnected without oper-
ating the water release function
during cold weather, the vehicle
may not start due to the fuel cell
system being frozen. To prevent
this, operate th e water release
function before removing the bat-
tery or disconnecting the termi-
nals. ( P.196)

4888-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
■When replacing the 12-volt bat-
tery
●Use a Central Degassing type 12-
volt battery (European Regula-
tions).
●Use a 12-volt battery with the
same case size as the previous
12-volt battery and an equivalent
20 hour rate capacity (20HR) or
greater.
• If the sizes differ, the 12-volt bat- tery cannot be properly secured.
• If the 20 hour rate capacity is low,
even if the time period where the
vehicle is not used is a short time,
the 12-volt battery may discharge
and the fuel cell system may not
be able to start.
●Use a 12-volt battery with a han-
dle. If a 12-volt b attery without a
handle is used, removal is more
difficult.
●After replacing, firmly attach the
following items to the exhaust hole
of the 12-volt battery.
• Use the exhaust hose that was
attached to the 12-volt battery
before replacing an d confirm that
it is firmly connected to the hole
section of t he vehicle.
• Use the exhaust hole plug included with the 12-volt battery
replaced or the one installed on
the 12-volt battery prior to the
replacement. (Depending on the
12-volt battery to be replaced, the
exhaust hole may be plugged.)
Exhaust hole plug
Exhaust hole
Exhaust hose For details, consult your Toyota
dealer.
WARNING
■When removing the 12-volt
battery terminals
Always remove the negative (-)
terminal first. If the positive (+) ter-
minal contacts any metal in the
surrounding area when the posi-
tive (+) terminal is removed, a
spark may occur, leading to a fire
in addition to ele ctrical shocks
and death or serious injury.
■Avoiding 12-volt battery fires
or explosions
Observe the following precautions
to prevent accidentally igniting the
flammable gas that may be emit-
ted from the 12-volt battery:
●Make sure each jumper cable is
connected to the correct termi-
nal and that it is not unintention-
ally in contact with any other
than the intended terminal.
●Do not allow the other end of
the jumper cable connected to
the “+” terminal 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
into contact with each other.
●Do not smoke, use matches,
cigarette lighter s or allow open
flame near the 1 2-volt battery.
■12-volt battery precautions
The 12-volt battery contains poi-
sonous and corrosive acidic elec-
trolyte, while related parts contain
lead and lead compounds.
Observe the following precautions
when handling the 12-volt battery:

4898-2. Steps to take in an emergency
Owners Manual_USA_M62064_en
8
When trouble arises
WARNING
●When working with the 12-volt
battery, always wear safety
glasses and take care not to
allow any battery fluids (acid) to
come into contact with skin,
clothing or the vehicle body.
●Do not lean over the 12-volt bat-
tery.
●In the event that battery fluid
comes into contact with the skin
or eyes, immediately wash the
affected area with water and
seek medical attention. Place a
wet sponge or cloth over the
affected area until medical
attention can be received.
●Always wash your hands after
handling the 12-volt battery sup-
port, terminals, and other bat-
tery-related parts.
●Do not allow child ren near the
12-volt battery.
■After recharging the 12-volt
battery
Have the 12-volt battery
inspected at your Toyota dealer
as soon as possible.
If the 12-volt battery is deteriorat-
ing, continued use may cause the
12-volt battery to emit a malodor-
ous gas, which may be detrimen-
tal to the health of passengers.
■When replacing the 12-volt
battery
●When the vent plug and indica-
tor are close to the hold down
clamp, the battery fluid (sulfuric
acid) may leak.
●For information regarding 12-
volt battery rep lacement, con-
tact your Toyota dealer.
●After replacing, s ecurely attach
the exhaust hose and exhaust
hole plug to the exhaust hole of
the replaced 12-volt battery. If
not properly installed, gases
(hydrogen) may leak into the
vehicle interior, and there is the
possible danger of the gas ignit-
ing and exploding.
NOTICE
■When handling jumper cables
When connecting the jumper
cables, ensure that they do not
become entangled in the cooling
fan.
■When connecting jumper
cables
Make sure to connect jumper
cables to the specified terminals
and connecting point. Failure to
do so may adversely affect the
electronic devices or damage to
them.
■To prevent damaging the
vehicle
The exclusive jump starting termi-
nal is to be used when charging
the 12-volt battery from another
vehicle in an emergency. It cannot
be used to jump start another
vehicle.

5119-1. Specifications
Owners Manual_USA_M62064_en
9
Vehicle specifications
*: Table 1 -Occupant loading and di stribution for vehicle normal load for var-
ious designated seating capacities
Tread ribA tread section running circumferentially
around a tire
Tread separationPulling away of the tread from the tire car-
cass
Treadwear indicators (TWI)
The projections within the principal
grooves designed to give a visual indica-
tion of the degrees o f wear of the tread
Wheel-holding fixtureThe fixture used to hold the wheel and tire
assembly securely during testing
Tire related termMeaning
Designated seating
capacity, Number of occupantsVehicle normal load,
Number of occupantsOccupant distribution in a normally loaded vehi- cle
2 through 422 in front
5 through 1032 in front, 1 in second
seat
11 through 155
2 in front, 1 in second
seat, 1 in third seat, 1 in fourth seat
16 through 207
2 in front, 2 in second
seat, 2 in third seat, 1 in fourth seat

5169-2. Customization
Owners Manual_USA_M62064_en
■Smart key system and wireless remote control (P.127, 133,
136)
■Smart key system ( P.127, 133, 136)
■Wireless remote control ( P.125, 127, 134)
FunctionDefault settingCustomized
setting
Operating signal (Buzzers)5OffO—O1 to 7
Operation signal (Emergency
flashers)OnOffO—O
Time elapsed before auto-
matic door lock function is
activated if door is not
opened after being unlocked
60 seconds
Off
O—O30 seconds
120 seconds
Open door warning buzzerOnOff——O
FunctionDefault settingCustomized setting
Smart key systemOnOff——O
Smart door unlockingDriver’s doorAll the doorsO—O
Time elapsed before unlock-
ing all the door when gripping
and holding the driver’s door
handle
2 seconds
Off
——O1.5 seconds
2.5 seconds
Number of consecutive door
lock operations2 timesAs many as desired——O
FunctionDefault settingCustomized setting
Wireless remote controlOnOff——O
Unlocking operation
Driver’s door unlocked in
one step, all doors
unlocked in two step
All doors
unlocked in one step
O—O

52910-1. For owners
Owners Manual_USA_M62064_en
10
For owners
 Tirez sur la ceinture épaulière
jusqu’à ce qu’elle recouvre
entièrement l’épaule; elle ne
doit cependant pas toucher le
cou ni glisser de l’épaule.
 Placez la ceinture abdominale
le plus bas possible sur les
hanches.
 Réglez la position du dossier.
Tenez-vous assis bien au
fond du siège, le dos droit.
 Ne vrillez pas la ceinture de
sécurité.
■Manipulation des ceintures
de sécurité
Avec un chiffon ou une éponge,
nettoyez à l’aide d’un savon
doux et de l’eau tiède. Vérifiez
aussi les ceintures régulière-
ment pour vous assurer qu’elles
ne présentent pas d’usure
excessive, d’effilochage ou de
coupures.
Seat belt instructions
for Canadian owners
(in French)
The following is a French
explanation of seat belt
instructions extracted from
the seat belt section in this
manual.
See the seat belt section for
more detailed seat belt
instructions in English.
Utilisation adéquate des
ceintures de sécurité
Entretien et nettoyage
AVERTISSEMENT
■Dommages et usure de la
ceinture de sécurité
Vérifiez périodiquement le sys-
tème de ceintures de sécurité.
Vérifiez qu’il n’y a pas de cou-
pures, d’effilochures ni de pièces
desserrées. N’utilisez pas une
ceinture de sécurité endommagée
avant qu’elle ne soit remplacée.
Les ceintures de sécurité endom-
magées ne peuvent pas protéger
les occupants contre les bless-
ures graves, voire mortelles.