2021 TOYOTA SIENNA HYBRID change key battery

901-5. Theft deterrent system
If a door is unlocked using the
mechanical key while the alarm is
set, a warning will sound intermit-
tently for approximately 10 seconds.
If the alarm is not canceled or
stopped during this time, the warn-
ing pattern change s and the warn-
ing sounds for a certain period of
time.
●A person inside the vehicle opens
a door or hood, or unlocks the
vehicle using an inside lock but-
ton.
●The 12-volt battery is recharged or
replaced when the vehicle is
locked. ( P.506)
■Alarm-operated door lock
In the following cases, depending
on the situation, th e door may auto-
matically lock to p revent improper
entry into the vehicle:
●When a person left in the vehicle
triggers the alarm by unlocking a
door or the back door.
●When a person lef t in the vehicle
unlocks a door or the back door
while the alarm is operating.
●When recharging or replacing the
12-volt battery.
NOTICE
■To ensure the system oper-
ates correctly
Do not modify or remove the sys-
tem. If modified or removed, the
proper operation of the system
cannot be guaranteed.

1673-2. Opening, closing and locking the doors
3
Before driving
hybrid system is started or power
switch modes are changed.
●Do not leave the electronic key on
top of the instrument panel or near
the door pockets when exiting the
vehicle. Depending on the radio
wave reception conditions, it may
be detected by the antenna out-
side the cabin and the door will
become lockable from the outside,
possibly trapping the electronic
key inside the vehicle.
●As long as the electronic key is
within the effective range, the
doors may be locked or unlocked
by anyone. However, only the
doors detecting the electronic key
can be used to unl ock the vehicle.
●Even if the electronic key is not
inside the vehicle, it may be possi-
ble to start the hybrid system if the
electronic key is near the window.
●The doors may unlock if a large
amount of water splashes on the
door handle, such as in the rain or
in a car wash when the electronic
key is within the effective range.
(The doors will automatically be
locked after approximately 60 sec-
onds if the doors are not opened
and closed.)
●If the wireless remote control is
used to lock the doors when the
electronic key is near the vehicle,
there is a possib ility that the door
may not be unlocke d by the entry
function. (Use the wireless remote
control to unloc k the doors.)
●Touching the door lock sensor
while wearing gloves may delay or
prevent lock operation. Remove
the gloves and touch the lock sen-
sor again.
●When the lock op eration is per-
formed using the lock sensor, rec-
ognition signals will be shown up
to two consecutive times. After
this, no recogniti on signals will be
given.
●If the door handle becomes wet
while the electronic key is within the effective range, the door may
lock and unlock repeatedly. In that
case, follow the
following correc-
tion procedures to wash the vehi-
cle:
• Place the electronic key in a loca-
tion 6 ft. (2 m) or more away from
the vehicle. (Take care to ensure
that the key is not stolen.)
• Set the electronic key to battery- saving mode to disable the smart
key system. ( P.166)
●If the electronic key is inside the
vehicle and a door handle
becomes wet during a car wash, a
message may be shown on the
multi-information display and a
buzzer will sound outside the vehi-
cle. To turn off th e alarm, lock all
the doors.
●The lock sensor may not work
properly if it comes into contact
with ice, snow, m ud, etc. Clean
the lock sensor and attempt to
operate it again, or use the lock
sensor on the lower part of the
door handle.
●A sudden approach to the effec-
tive range or door handle may pre-
vent the doors from being
unlocked. In this case, return the
door handle to the original position
and check that t he doors unlock
before pulling the door handle
again.
●If there is another electronic key in
the detection area, it may take
slightly longer to unlock the doors
after the door handle is gripped.
■When the vehicle is not driven
for extended periods
●Vehicles with entry function: To
prevent theft of the vehicle, do not
leave the electronic key within 6 ft.
(2 m) of the vehicle.
●The smart key system can be
deactivated in advance. ( P.544)
●Battery-saving mode can reduce
the power consumption of elec-
tronic keys. ( P.166)

2324-2. Driving procedures
■When the ambient temperature
is low, such as during winter
driving conditions
When starting the hybrid system,
the flashing time of the “READY”
indicator may be long. Leave the
vehicle as it is u ntil the “READY”
indicator is steady on, as steady
means the vehicle is able to move.
■Sounds and vibrations specific
to a hybrid vehicle
 P.81
■If the 12-volt battery is dis-
charged
The hybrid system cannot be
started using the smart key system.
Refer to P.506to re start the hybrid
system.
■Electronic key battery depletion
 P.128
■Conditions affecting operation
 P.166
■Note for the entry function
 P.166
■Steering lock function
●After turning the power switch to
OFF and opening and closing the
doors, the steer ing wheel will be
locked due to the steering lock
function. Operating the power
switch again automatically can-
cels the steering lock.
●When the steering lock cannot be
released, “Push Power Switch
while Turning the Steering Wheel
in Either Direction” will be dis-
played on the multi-information
display.
Check that the shift lever is set in
P. Press the power switch shortly
and firmly while turning the steer-
ing wheel left and right.
●To prevent the steering lock motor
from overheating , the motor may
be suspended if the hybrid system
is turned on and off repeatedly in
a short period of ti me. In this case,
refrain from operating the power
switch. After about 10 seconds,
the steering lo ck motor will
resume functioning.
■If there is a malfunction in the
smart key system
If “Smart Key System Malfunction
See Owner’s Manual” is displayed
on the multi-information display, the
system may be malfunctioning.
Have the vehicle inspected by your
Toyota dealer immediately.
■If the “READY” indicator does
not come on
In the event that the “READY” indi-
cator does not come on even after
performing the proper procedures
for starting the vehicle, contact your
Toyota dealer immediately.
■When “Check Fuel Cap” is dis-
played on the multi-information
display
 P.261
■If the hybrid sys tem is malfunc-
tioning
 P.86
■Electronic key battery
 P.447
■Operation of the power switch
●If the switch is not pressed shortly
and firmly, the power switch mode
may not change o r the hybrid sys-
tem may not start.
●If attempting to res tart the hybrid

2344-2. Driving procedures
the vehicle as is or selecting “Per-
form Auto Off” keeps the auto-
matic hybrid system shut off
feature enabled, or selecting
“Keep Vehicle On” disables the
automatic hybrid system shut off
feature.
●The timer for the automatic hybrid
system shut off feature will reset if
the brake pedal is depressed or if
the shift lever is in a position other
than P.
●After the vehicle is parked, if the
door is locked with the door lock
switch ( P.135) from the inside
or the mechanical key ( P.504)
from the outside, the automatic
hybrid system shut off fe ature will
be disabled. The timer for the
automatic hybrid system shut off
feature will be re-enabled if the
driver’s door is opened.
Modes can be changed by
pressing the power switch with
the brake pedal released. (The
WARNING
■Stopping the hybrid system
in an emergency
●If you want to stop the hybrid
system in an emergency while
driving the vehicle, press and
hold the power switch for more
than 2 seconds, or press it
briefly 3 times or more in suc-
cession. ( P.459)
However, do not touch the
power switch while driving
except in an emergency. Turn-
ing the hybrid system off while
driving will not cause loss of
steering or braking control, how-
ever, power assist for the steer-
ing wheel may be lost making it
difficult to steer smoothly before
stopping the vehicle depending
on the remaining charge in the
12-volt battery or usage condi-
tions. In this situation, you
should pull over and stop the
vehicle as soon as it is safe to
do so.
●If the power switch is operated
while the vehicle is running, a
warning message will be shown
on the multi-information display
and a buzzer sounds.
●When restarting the hybrid sys-
tem after an emergency shut-
down, shift the shift lever to N
and press the power switch
shortly and firmly.
■When parking
Exhaust gases include harmful
carbon monoxide (CO), which is
colorless and odorless. Observe
the following precautions.
Failure to do so may cause
exhaust gases to enter the vehicle
and may lead to an accident
caused by light-headedness, or
may lead to death or a serious
health hazard.
●If the vehicle is in a poorly venti-
lated area or a closed area,
such as a garage, stop the
hybrid system.
●Do not leave the vehicle with
the hybrid system operating for
a long time. If such a situation
cannot be avoided, park the
vehicle in an open space and
ensure that exhaust fumes do
not enter the ve hicle interior.
●Do not leave the hybrid system
operating in an area with snow
build-up, or where it is snowing.
If snowbanks build up around
the vehicle while the hybrid sys-
tem is operating, exhaust gases
may collect and enter the vehi-
cle.
Changing power switch
modes

2494-3. Operating the lights and wipers
4
Driving
■Headlight control sensor
The sensor may not function prop-
erly if an object is placed on the sen-
sor, or anything that blocks the
sensor is affixed to the windshield.
Doing so interfere s with the sensor
detecting the level of ambient light
and may cause the automatic head-
light system to malfunction.
■Automatic light off system
●When the headlights are on: The
lights turn off 30 seconds after the
power switch is turned to ACC or
OFF and a door is opened and
closed. (The lights turn off imme-
diately if on the key is
pressed after all the doors are
closed.)
●When only the tail lights are on:
The tail lights turn off automati-
cally if the power switch is turned
to ACC or OFF and the driver’s
door is opened.
Except for Canada: To turn the
lights on again, turn the power
switch to ON, or turn the light switch
off once and the n back to or
position.
For Canada: To turn the lights on
again, turn the power switch to ON,
or turn the light s witch to once
and then back to or posi-
tion.
■Light reminder buzzer
A buzzer sounds when the power
switch is turned to ACC or OFF and
the driver’s door is opened while the
lights are turned on.
■Windshield wiper linked head-
light illumination (if equipped)
When driving during daytime with
the headlight switch turned to , if
the windshield wipers are used, the
headlights will turn o n automatically
after several se conds to help
enhance the visibility of your vehi-
cle.
■12-volt battery-saving function
In order to prevent the 12-volt bat-
tery of the vehicle from discharging,
if the headlights and/or tail lights are
on when the power switch is turned
to OFF, the battery saving function
will operate and au tomatically turn
off all the lights af ter approximately
20 minutes.
When any of the following are per-
formed, the battery-saving function
is canceled once and then reacti-
vated. All the light s will turn off auto-
matically 20 minutes after the
battery-saving function has been
reactivated:
●When the headlight switch is oper-
ated
●When a door is opened or closed
■If “Headlight System Malfunc-
tion Visit Your Dealer” is dis-
played on the multi-information
display
The system may be malfunctioning.
Have the vehicle inspected by your
Toyota dealer.
■Welcome light illumination con-
trol
The parking lights and tail lights
automatically turn on at night when
the doors are un locked using the
entry function or wireless remote
control if the light switch is in the
position.
■Customization
Settings (e.g. light sensor sensitiv-
ity) can be changed.
(Customizable features: P.548)

3655-2. Using the interior lights
5
Interior features
together the front interior lights.
When a door is opened while the
front and rear interior light door
position is on, the lights turn on.
2Turns the light on
■Illuminated entry system
The lights automati cally turn on/off
according to the power switch
mode, the presence of the elec-
tronic key, whether the doors are
locked/unlocked, and whether the
doors are opened/closed.
■To prevent the 12-volt battery
from being discharged
If the interior lights remain on when
the power switch is turned to OFF,
the lights will go off automatically
after 20 minutes.
■The interior lights will turn on
automatically when
If any of the SRS airbags deploy
(inflate) or in the event of a strong
rear impact, the interior lights will
turn on automatically.
The interior lights will turn off auto-
matically after approximately 20
minutes.
The interior lights can be turned off
manually. However, in order to help
prevent further collisions, it is rec-
ommended that they be left on until
safety can be ensured.
(The interior lights may not turn on
automatically depending on the
force of the impact and conditions of
the collision.)
■Customization
Setting (e.g. the time elapsed before
the lights turn off) can be changed.
(Customizable features: P.552)
NOTICE
■To prevent 12-volt battery dis-
charge
Do not leave the lights on longer
than necessary when the hybrid
system is off.

5057-2. Steps to take in an emergency
7
When trouble arises
1Ensure that the shift lever is
in P and depress the brake
pedal.
2 Touch the electronic key to
the power switch as shown in
the illustration.
When the electronic key is
detected, a buzzer sounds and the
power switch will turn to ON.
When the smart key system is
deactivated in customization set-
ting, the power switch will turn to
ACC.
3Firmly depress the brake
pedal and check that is displayed on the multi-infor-
mation display.
4 Press the power switch
shortly and firmly.
In the event that t he hybrid system
still cannot be started, contact your
Toyota dealer.
■Stopping the hybrid system
Shift the shift lever to P, set the
parking brake and press the power
switch as you normally do when
stopping the hybrid system.
■Replacing the key battery
As the above proce dure is a tempo-
rary measure, it is recommended
that the electronic key battery be
replaced immediately when the bat-
tery is depleted. ( P.447)
■Changing power switch modes
Release the brake pedal and press
the power switch in step 3 above.
The hybrid system does not start
and modes will be changed each
time the switch is pressed.
(  P.234)
WARNING
■When using the mechanical
key and operating the power
windows or the moon roof (if
equipped)
Operate the power window or the
moon roof after checking to make
sure that there is n o possibility of
any passenger having any of their
body parts caught in the window
or the moon roof. 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 or
the moon roof.
Starting the hybrid sys-
tem