2021 TOYOTA SIENNA HYBRID fuel

3545-1. Using the air conditioning system and defogger
for functions other than that
operated is maintained.
■Using automatic mode
Fan speed is adjusted automati-
cally according to the temperature
setting and the ambient conditions.
Therefore, the fan may stop for a
while until warm or cool air is ready
to flow immediately after the auto-
matic mode switch is pressed.
This function automatically con-
trols the air conditioning airflow
so that priority is given to the
front seats. When the front pas-
senger seat is not occupied, air-
flow may switch to only the
driver’s seat. Unnecessary air
conditioning is suppressed, con-
tributing to increased fuel effi-
ciency.
Front seat concentrated airflow
mode operates in the following
situations.
 No passengers are detected
in the rear seats
 The windshield defogger is
not operating
While operating, illumi-
nates.
■Manually turning front seat
concentrated airflow mode
on/off
In front seat concentrated air-
flow mode, directing airflow to the front seats only and to all
seats can be switched via switch
operation. When the mode has
been switched manually, auto-
matic airflow control stops oper-
ating.
Press on the air condition-
ing operation panel and switch
the airflow.

Indicator illuminated: Airflow
to the front seats only
 Indicator off: Airflow to all the
seats
■Operation of automatic airflow
control
●In order to maintain a comfortable
interior, airflow may be directed to
seats without passengers immedi-
ately after the hybrid system is
started and at other times depend-
ing on the outside temperature.
●After the hybrid system is started,
if passengers move around inside
or enter/exit the vehicle, the sys-
tem cannot accura tely detect the
presence of passengers and auto-
matic airflow co ntrol will not oper-
ate.
■Operation of manual airflow
control
Even if the funct ion is manually
switched to directing airflow to only
the front seats, w hen a rear seat is
occupied, it may automatically direct
airflow to all seats.
■To return to automatic airflow
control
1 With the indicator off, turn the
power switch off.
2 After 60 minutes or more elapse,
turn the power switch to ON.
Front seat concentrated
airflow mode (S-FLOW)

4066-2. Maintenance
6-2.Maintenance
■Repair and replacement
It is recommended that genuine
Toyota parts be used for repairs to
ensure performanc e of each sys-
tem. If non-Toyota p arts are used in
replacement or if a repair shop other
than a Toyota dealer performs
repairs, confirm the warranty cover-
age.
■Allow inspection and repairs to
be performed by a Toyota
dealer
●Toyota technicians are well-
trained specialists and are kept up
to date with the latest service
information. They are well
informed about the operations of
all systems on your vehicle.
●Keep a copy of the repair order. It
proves that the maintenance that
has been performed is under war-
ranty coverage. If any problem
should arise while your vehicle is
under warranty, your Toyota
dealer will promptly take care of it.
General maintenance should be
performed on a daily basis. This
can be done by yourself or by a
Toyota dealer.
Scheduled maintenance should
be performed at specified inter-
vals according to the mainte-
nance schedule.
For details about maintenance
items and schedules, refer to the
“Scheduled Maintenance Guide” or
“Owner’s Manual Supplement”.
Maintenance require-
ments
To ensure safe and econom-
ical driving, day-to-day care
and regular maintenance
are essential. It is the
owner’s responsibility to
perform regular checks.
Toyota recommends the fol-
lowing maintenance:
WARNING
■If your vehicle is not properly
maintained
Improper maintenance could
result in serious damage to the
vehicle and possible death or seri-
ous injury.
■Handling of the 12-volt bat-
tery
●Engine exhaust, some of its
constituents, and a wide variety
of automobile components con-
tain or emit chemicals known to
the State of California to cause
cancer and birth defects and
other reproductive harm. Work
in a well ventilated area.
●Oils, fuels and fluids contained
in vehicles as well as waste pro-
duced by component wear con-
tain or emit chemicals known to
the State of California to cause
cancer and birth defects or
other reproductive harm. Avoid
exposure and wash any
affected area immediately.
●12-volt battery posts, terminals
and related accessories con-
tain lead and lead compounds
which are known to cause brain
damage. Wash your hands after
handling. ( P.422)
General maintenance
Scheduled maintenance

4106-2. 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 loose
The malfunction indicator
lamp comes on indicating a
temporary malfunction and
your vehicle may not pass the
I/M test.
The error code in the OBD sys-
tem will not be cleared unless
the vehicle is driven 40 or more
times.
Contact your Toyota dealer to
prepare the vehicle for re-test-
ing.
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 malfunc tion indica-
tor lamp comes on
Your vehicle may not
pass the I/M test in the fol-
lowing situations:
When the malfunction
indicator lamp still
remains on after several
driving trips
If your vehicle does not
pass the I/M test

4126-3. Do-it-yourself maintenance
Hybrid bat-
tery (traction
battery) air
intake vent
( P.443)• Vacuum cleaner,
etc,
• Phillips screw- driver
Light bulbs
( P.451)
• Bulb with same
number and watt-
age rating as origi-
nal
• Phillips-head screwdriver
• Flathead screw- driver
• Wrench
Radiator and
condenser
(  P.420)

Tire inflation
pressure
( P.438)• Tire pressure
gauge
• Compressed air source
Washer fluid
( P.421)
• 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.420)
■Safety glasses
Wear safety gla sses to prevent
flying or falling material, fluid
spray, etc., from getting in your
eyes.

4396-3. Do-it-yourself maintenance
6
Maintenance and care
Do not forget to check the spare.
■Effects of incorrect tire inflation
pressure
Driving with incorrect tire inflation
pressure may result in the following:
●Reduced fuel economy
●Reduced driving comfort and poor
handling
●Reduced tire life due to wear
●Reduced safety
●Damage to the drive train
If a tire needs frequent inflating,
have it checked b y your Toyota
dealer.
■Instructions for checking tire
inflation pressure
When checking tire inflation pres-
sure, observe the following:
●Check only when the tires are
cold.
If your vehicle has been parked
for at least 3 hours or has not
been driven for more than 1 mile
or 1.5 km, you will get an accurate
cold tire inflation pressure reading.
●Always use a tire pressure gauge.
It is difficult to judge if a tire is
properly inflated based only on its
appearance.
●It is normal for the tire inflation
pressure to be higher after driving
as heat is generated in the tire. Do
not reduce tire inflation pressure
after driving.
●Never exceed the vehicle capacity
weight. Passengers and luggage
weight should be placed so that
the vehicle is balanced.
WARNING
■Proper inflation is critical to
save tire performance
Keep your tires properly inflated.
If the tires are not properly
inflated, the following conditions
may occur which could lead to an
accident resulting in death or seri-
ous injury:
●Excessive wear
●Uneven wear
●Poor handling
●Possibility of blowouts resulting
from overheated tires
●Air leaking from between tire
and wheel
●Wheel deformation and/or tire
damage
●Greater possibi lity of tire dam-
age while driving (due to road
hazards, expansion joints,
sharp edges in the road, etc.)
NOTICE
■When inspecting and adjust-
ing tire inflation pressure
Be sure to put the tire valve caps
back on.
If a valve cap is no t installed, dirt
or moisture may get into the valve
and cause an air leak, resulting in
decreased tire inflation pressure.

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)

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