2021 TOYOTA SIENNA HYBRID battery

4236-3. Do-it-yourself maintenance
6
Maintenance and care
Remove the cover.
Make sure that the 12-volt bat-
tery terminals are not corroded
and that there are no loose con-
WARNING
●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 insuf-
ficient ventilation.
■Emergency measures regard-
ing electrolyte
●If electrolyte gets in your eyes
Flush your eyes with clean water
for at least 15 minutes and get
immediate medical attention. If
possible, continue to apply water
with a sponge or cloth while trav-
eling to the nearest medical facil-
ity.
●If electrolyte gets on your skin
Wash the affected area thor-
oughly. 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
clothing and follow the procedure
above if necessary.
●If you accidentally swallow elec-
trolyte
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. Failu re 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.
■When there is insufficient 12-
volt battery fluid
Do not use if ther e is insufficient
fluid in the 12-volt battery. There
is a possible danger that the 12-
volt battery may explode.
NOTICE
■When recharging the 12-volt
battery
Never recharge t he 12-volt bat-
tery while the hybrid system is
operating. Also, be sure all acces-
sories are turned off.
Removing the 12-volt bat-
tery cover
Exterior

4436-3. Do-it-yourself maintenance
6
Maintenance and care
Remove the dust from the air
intake vents with a vacuum
cleaner, etc.
Make sure to only use a vacuum to
suck out dust and clogs. Attempting
to blow out dust and clogs using an
airgun, etc. may push it into the air
intake vent. (P.446)
NOTICE
■When using the air condition-
ing system
Make sure that a filter is always
installed. Using the air condition-
ing system without a filter may
cause damage to the system.
■When removing the glove box
Always follow the specified proce-
dure to remove the glove box
(  P.441). If the glove box is
removed without following the
specified procedure, the hinge of
the glove box may become dam-
aged.
■To prevent damage to the fil-
ter cover
When moving the filter cover in
the direction of arrow to release
the fitting, pay attention not to
apply excessive force to the
claws. Otherwise, the claws may
be damaged.
Cleaning the hybrid
battery (traction bat-
tery) air intake vents
and filters
To prevent the fuel econ-
omy from being affected,
visually inspect the hybrid
battery (traction battery) air
intake vents periodically for
dust and clogs. If they are
dusty or clogged or if
“Maintenance Required for
Traction Battery Cooling
Parts See Owner’s Manual”
is shown on the multi-infor-
mation display, clean the air
intake vents using the fol-
lowing procedures:
Cleaning the air intake
vents

4456-3. Do-it-yourself maintenance
6
Maintenance and care
7Install the air intake vent
cover.
Insert the tab of the cover as shown
in the illustrati on and push the
cover to engage the claws.
8 Using a Phillips screwdriver,
install the clip.
■Scheduled maintenance of the
air intake vents is necessary
when
In some situations such as when the
vehicle is used frequently or in
heavy traffic or dusty areas, the air
intake vents may need to be
cleaned more regularly. For details,
refer to “Scheduled Maintenance
Guide” or “Owner’s Manual Supple-
ment”.
■Cleaning the air intake vents
●Dust in the air in take vents may
interfere with the cooling of the
hybrid battery (traction battery). If
charging/discharging of the hybrid
battery (traction battery) becomes
limited, the distance that the vehi-
cle can be driven using the electric motor (traction motor) may be
reduced and the fuel economy
may be reduced. Inspect and
clean the air intake vents periodi-
cally.
●Improper handling of the air intake
vent covers and filters may result
in damage to them. If you have
any concerns about cleaning the
filters, contact your Toyota dealer.
■If “Maintenance Required for
Traction Battery Cooling Parts
See Owner’s Manual” is shown
on the multi-information display
●If this warning message is shown
on the multi-information display,
remove the air intake vent covers
and clean the filters. (
P.444)
●After cleaning the air intake vents,
start the hybrid system and check
that the warning message is no
longer shown.
It may take approximately 20 min-
utes after the hybrid system is
started until the warning message
disappears. If the warning mes-
sage does not disappear, have
the vehicle inspected by your
Toyota dealer.
WARNING
■When cleaning the air intake
vents
●Do not use water or other liq-
uids to clean the air intake
vents. If water is applied to the
hybrid battery (traction battery)
or other components, a mal-
function or fire may occur.
●Before cleaning the air intake
vents, make sure to turn the
power switch off to stop the
hybrid system.
■When removing the air intake
vent covers
Do not touch the service plug
located underneath the console
box. ( P.84)

4466-3. Do-it-yourself maintenance
NOTICE
■When cleaning the air intake
vents
When cleaning the air intake
vents, make sure to only use a
vacuum to suck out dust and
clogs. If a compressed air blow
gun, etc. is used to blow out dust
and clogs, the dust or clogs may
be pushed into the air intake
vents, which may affect the per-
formance of the hybrid battery
(traction battery) and cause a
malfunction.
■To prevent damage to the
vehicle
●Do not allow water or foreign
matter to enter t he air intake
vents when the covers are
removed.
●Carefully handle the removed
filter so that it will not be dam-
aged. If the filter is damaged,
have it replaced with a new filter
by your Toyota dealer.
●Make sure to reinstall the filters
and covers to their original posi-
tions after cleaning.
●Do not install anything to the air
intake vents other than the
exclusive filters for this vehicle
or use the vehicle without the fil-
ters installed.
■If “Maintenance Required for
Traction Battery Cooling
Parts See Owner’s Manual” is
shown on the multi-informa-
tion display
If the vehicle is continuously
driven with the warning message
(indicating that charging/discharg-
ing of the hybrid battery [traction
battery] may become limited) dis-
played, the hybrid battery (traction
battery) may malfunction. If the
warning message is displayed,
clean the air intake vents immedi-
ately.

4476-3. Do-it-yourself maintenance
6
Maintenance and care
■If the key battery is depleted
The following symptoms may occur:
●The smart key system and wire-
less remote contr ol will not func-
tion properly.
●The operational range will be
reduced.
Prepare the following before
replacing the battery:
 Flathead screwdriver
 Small flathead screwdriver
 Lithium battery CR2450
■Use a CR2450 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 manufacturer.
●Dispose of used ba tteries accord-
ing to the local laws.
1 Release the lock and remove
the mechanical key.
2 Remove the key cover.
Use a screwdriver of an appropriate
size. Forcedly prying may cause
the cover damaged.
To prevent damage to the key,
cover the tip of the flathead screw-
driver with a rag.
3Remove the depleted battery
using a small flathead screw-
driver.
When removing the cover, the elec-
tronic key module may stick to the
cover and the batt ery may not be
visible. In this case, remove the
electronic key module in order to
remove the battery.
When removing the battery, use a
screwdriver of an appropriate size.
Insert a new battery with the “+” ter-
Electronic key battery
Replace the battery with a
new one if it is depleted.
Items to prepare
Replacing the battery

4486-3. Do-it-yourself maintenance
minal facing up.
4When installing, reverse the
steps listed.
WARNING
■Battery precautions
Observe the following precau-
tions.
Failure to do so m ay result in
death or serious injury.
●Do not swallow the battery.
Doing so may cause chemical
burns.
●A coin battery or button battery
is used in the electronic key. If a
battery is swallowed, it may
cause severe chemical burns in
as little as 2 hours and may
result in death or serious injury.
●Keep away new and removed
batteries from children.
●If the cover cannot be firmly
closed, stop using the electronic
key and stow the key in the
place where children cannot
reach, and then contact your
Toyota dealer.
●If you accidentally swallow a
battery or put a b attery into a
part of your body, get emer-
gency medical attention imme-
diately.
■To prevent battery explosion
or leakage of flammable liq-
uid or gas
●Replace the battery with a new
battery of the same type. If a
wrong type of battery is used, it
may explode.
●Do not expose batteries to
extremely low pr essure due to
high altitude or extremely high
temperatures.
●Do not burn, bre ak or cut a bat-
tery.
NOTICE
■When replacing the battery
Use a flathead screwdriver of
appropriate size. Applying exces-
sive force may deform or damage
the cover.
■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.

457
7
7
When trouble arises
When trouble arises
7-1. Essential informationEmergency flashers .... 458
If your vehicle has to be stopped in an emergency.................................. 459
If the vehicle is trapped in rising water ................ 460
7-2. Steps to take in an emer- gency
If your vehicle needs to be towed......................... 462
If you think something is wrong ........................ 465
If a warning light turns on or a warning buzzer sounds.................................. 466
If a warning message is dis- played........................ 477
If you have a flat tire (vehi- cles without spare tire) 481
If you have a flat tire (vehi- cles with spare tire) ... 491
If the hybrid system will not start ........................... 501
If you lose your keys ... 502
If the fuel filler door cannot be opened ................. 503
If the electronic key does not operate properly .. 504
If the 12-volt battery is dis- charged ..................... 506
If your vehicle overheats .................................. 511If the vehicle becomes stuck
.................................. 514

4747-2. Steps to take in an emergency
seat.
●If a cushion is placed on the seat,
the sensor may not 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
sensors, “AIR BAG ON” indicator
light, “AIR BAG OFF” indicator light,
front passenger’s seat belt buckle
switch, seat belt pretensioners and
force limiters, airbags, interconnect-
ing wiring and power sources.
(  P.42)
■If the malfunction indicator
lamp comes on while driving
First check the following:
●Is the fuel t ank empty?
If it is, fill the fuel tank immediately.
●Is the fuel tank cap loose?
If it is, tighten it securely.
The light will go o ff after several
driving trips.
If the light does not go off even after
several trips, contact your Toyota
dealer as soon as possible.
■Electric power steering system
warning light (warning buzzer)
When the 12-volt battery charge
becomes insufficien t 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.491 If none of the tires are punctured:
Turn the power switch to OFF then
turn it to ON.
Check if the tire pressure warning
light comes on or blinks.
If the tire pressur
e 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
at the specified level and perform
initialization. ( P.430)
■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 inflation
pressure changes caused by tem-
perature. In this ca se, adjusting the
tire inflation pressure will turn off the
warning ligh t (after a few minutes).
■When a tire is replaced with a
compact spare tire (vehicles
with compact spare tire)
The compact spare tire is not
equipped with a tire pressure warn-
ing valve and tran smitter. If a tire
goes flat, the tire pressure warning
light will not turn off even though the
flat tire has been replaced with the
spare tire. Replac e the spare tire
with the standard tire and adjust the
tire inflation pressure. The tire pres-
sure warning light will go off after a
few minutes.