2023 TOYOTA SIENNA HYBRID battery

4046-2. Maintenance
General maintenance
Listed below are the general
maintenance items that
should be performed at the
intervals specified in the
“Owner’s Warranty Informa-
tion Booklet” or “Owner’s
Manual Supplement/Sched-
uled Maintenance Guide”. It
is recommended that any
problem you notice should
be brought to the attention
of your Toyota dealer or
qualified service shop for
advice.
WARNING
■If the hybrid system is run-
ning
Turn the hybrid system off and
ensure that there is adequate
ventilation before performing
maintenance checks.
Engine compartment
ItemsCheck points
Brake fluid
Is the brake fluid at
the correct level?
(  P.417)
Engine/power
control unit
coolant
Is the
engine/power con-
trol unit coolant at
the correct level?
( P.416)
Engine oil
Is the engine oil at
the correct level?
( P.413)
Exhaust sys-
temThere should not
be any fumes or
strange sounds.
Radiator/con-
denser
The radiator and
condenser should
be free from for-
eign objects.
( P.417)
Washer fluid
Is there sufficient
washer fluid?
( P.418)
Luggage compartment
ItemsCheck points
12-volt batteryCheck the connec-
tions. ( P.419)
Vehicle interior
ItemsCheck points
Accelerator
pedal
• The accelerator
pedal should
move smoothly
(without uneven
pedal effort or
catching).
Hybrid trans-
mission “Park”
mechanism
• When parked on a slope and the
shift lever is in P,
is the vehicle
securely
stopped?
ItemsCheck points

4066-2. Maintenance
The OBD system determines
that a problem exists some-
where in the emission control
system. Your vehicle may not
pass the I/M test and may need
to be repaired. Contact your
Toyota dealer to service the
vehicle.
When the 12-volt battery is
disconnected or discharged
Readiness codes that are set
during ordinary driving are
erased.
Also, depending on your driv-
ing habits, the readiness
codes may not be completely
set.
 When the fuel tank cap is
Vehicle exterior
ItemsCheck points
Doors
• Do the doors
operate
smoothly?
Engine hood
• Does the engine hood lock system
work properly?
Fluid leaks
• There should not be any signs of
fluid leakage
after the vehicle
has been parked.
Tires
• Is the tire infla-tion pressure
correct?
• The tires should not be damaged
or excessively
worn.
• Have the tires been rotated
according to the
maintenance
schedule?
• The wheel nuts should not be
loose.
Windshield
wipers/rear
window wiper
• The wiper blades should not show
any signs of
cracking, split-
ting, wear, con-
tamination or
deformation.
• The wiper blades should clear the
windshield/rear
window without
streaking or skip-
ping.
Emission inspection
and maintenance (I/M)
programs
Some states have vehicle
emission inspection pro-
grams which include OBD
(On Board Diagnostics)
checks. The OBD system
monitors the operation of
the emission control sys-
tem.
If the malfunction indica-
tor lamp comes on
Your vehicle may not
pass the I/M test in the fol-
lowing situations:

4096-3. Do-it-yourself maintenance
6
Maintenance and care
Hybrid bat-
tery (traction
battery) air
intake vent
( P.440)• Vacuum cleaner,
etc,
• Phillips screw- driver
Light bulbs
( P.448)
• Bulb with same
number and watt-
age rating as origi-
nal
• Phillips-head screwdriver
• Flathead screw- driver
• Wrench
Radiator and
condenser
(  P.417)

Tire inflation
pressure
( P.435)• Tire pressure
gauge
• Compressed air source
Washer fluid
( P.418)
• Water or washer
fluid containing
antifreeze (for win-
ter use)
• Funnel (used only for adding water or
washer fluid)
WARNING
The engine compartment contains
many mechanisms and fluids that
may move suddenly, become hot,
or become electrically energized.
To avoid death or serious injury,
observe the following precautions.
ItemsParts and tools■When working on the engine
compartment
●Make sure that “IGNITION ON”
on the multi-information display
and the “READY” indicator are
both off.
●Keep hands, clothing and tools
away from the moving fan.
●Be careful not to touch the
engine, power control unit, radi-
ator, exhaust manifold, etc. right
after driving as they may be hot.
Oil and other fluids may also be
hot.
●Do not leave anything that may
burn easily, such as paper and
rags, in the engine compart-
ment.
●Do not smoke, cause sparks or
expose an open flame to fuel or
the battery. Fuel and battery
fumes are flammable.
●Be extremely cautious when
working on the battery. It con-
tains poisonous and corrosive
sulfuric acid.
■When working near the elec-
tric cooling fan or radiator
grille
Be sure the power switch is OFF.
With the power switch in ON, the
electric cooling fa n may automati-
cally start to run if the air condi-
tioning is on and/or the coolant
temperature is high. ( P.417)
■Safety glasses
Wear safety gla sses to prevent
flying or falling material, fluid
spray, etc., from getting in your
eyes.

4136-3. Do-it-yourself maintenance
6
Maintenance and care
Fuse box (P.446)
Engine oil filler cap ( P.414)
Engine oil level dipstick ( P.413)
Brake fluid reservoir ( P.417)
Radiator ( P.417)
Electric cooling fan
Condenser ( P.417)
Power control unit coolant reservoir ( P.416)
Washer fluid tank ( P.418)
Engine coolant reservoir ( P.416)
■12-volt battery
 P.419
With the engine at operating
temperature and turned off,
Engine compartment
Components
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B
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4196-3. Do-it-yourself maintenance
6
Maintenance and care
The 12-volt battery is located in
the right-hand side of luggage
compartment.
■Before recharging
When recharging, the 12-volt bat-
tery produces hydrogen gas which
is flammable and explosive. There-
fore, observe the following precau-
tions before recharging:
●If recharging with the 12-volt bat-
tery installed on the vehicle, be
sure to disconnect the ground
cable.
●Make sure the power switch on
the charger is off when connecting
and disconnecting the charger
cables to the 12-volt battery.
■After recharging/reconnecting
the 12-volt battery
●Unlocking the doors using the
smart key system may not be pos-
sible immediately after reconnect-
ing the 12-volt battery. If this
happens, use the wireless remote
control or the mechanical key to
lock/unlock the doors.
●Start the hybrid system with the
power switch in ACC. The hybrid
system may not start with the
power switch turned off. How-
ever, the hybrid system will oper-
ate 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 1
2-volt battery was dis-
connected. Make sure to turn off
the power switch before discon-
nect the 12-volt battery. Take
extra care when connecting the
12-volt battery if the power switch
mode prior to discharge is
unknown.
If the hybrid system will not start
even after multiple attempts at all
methods above, contact your
Toyota dealer.12-volt battery
Location
WARNING
■Chemicals in the 12-volt bat-
tery
The 12-volt battery contains poi-
sonous 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 touch-
ing 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 electro-
lyte.
●Wear protective safety glasses
when working near the 12-volt
battery.
●Keep children away from the
12-volt battery.

4206-3. Do-it-yourself maintenance
Remove the cover.
Make sure that the 12-volt bat-
tery terminals are not corroded
and that there are no loose con-
nections, cracks, or loose
clamps.
WARNING
■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. 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.
■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

4406-3. Do-it-yourself maintenance
■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 Supplement”.
■Cleaning the air intake vents
Improper handling of the air intake
vent covers and filt ers may result in
damage to them. If you have any
concerns about cleaning the filters,
contact your Toyota dealer.
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.438). 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
To prevent the fuel econ-
omy from being affected,
visually inspect the hybrid
battery (traction battery) air
intake vents periodically for
clogs.
If they are dusty or clogged
or if “Maintenance Required
for Traction Battery Cooling
Parts See Owner’s Manual”
is displayed on the multi-
information display, clean
the air intake vents using
the following procedures:

4416-3. Do-it-yourself maintenance
6
Maintenance and care
1Turn the power switch off.
2 Using a Phillips screwdriver,
remove the clip.
3 Remove the air intake vent
cover.
Pull the cover as shown in the illus-
tration to disengage the claws,
starting from the claw in the upper
right corner and pull the cover
toward the front of the vehicle to remove it.
4
Remove the filter from the air
intake vent cover.
Disengage the 3 center claws from
the filter.
If dust has accumula ted on the air
intake vent cover, remove the dust
with a vacuum cleaner, etc.
5 Remove the dust and sand
from the filter.
Using a vacuum cleaner, etc.,
absorb dust and sand from the filter
by profiling the nozzle lightly along
the fold.
NOTICE
■If “Maintenance Required for
Traction Battery Cooling
Parts See Owner’s Manual” is
displayed on the multi-infor-
mation display
Clean the air intake vents immedi-
ately.
If the vehicle is continuously
driven with the warning message
displayed, it may cause a mal-
function or output restriction of the
hybrid battery (tr action battery).
Cleaning procedure