2021 TOYOTA SIENNA HYBRID service

841-4. Hybrid system
■Running out of fuel
When the vehicle has run out of fuel
and the hybrid system cannot be
started, refuel th e vehicle with at
least enough gasoline to make the
low fuel level warning light ( P.472)
go off. If there is only a small
amount of fuel, th e hybrid system
may not be able to start. (The stan-
dard amount of fuel is about 3.1 gal.
[11.9 L, 2.6 Imp. gal.], when the
vehicle is on a level surface. This
value may vary whe n the vehicle is
on a slope. Add ext ra fuel when the
vehicle is inclined.)
■Electromagnetic waves
●High voltage parts and cables on
hybrid vehicles incorporate elec-
tromagnetic shielding, and there-
fore emit approximately the same
amount of electromagnetic waves
as conventional gasoline pow-
ered vehicles or home electronic
appliances.
●Your vehicle may cause sound
interference in so me third party-
produced radio parts.
■Hybrid battery (tr action battery)
The hybrid battery (traction battery)
has a limited service life. The lifes-
pan of the hybrid battery (traction
battery) can change in accordance
with driving style and driving condi-
tions.
WARNING
■High voltage precautions
This vehicle has high voltage DC
and AC systems as well as a 12-
volt system. DC and AC high volt-
age is very dangerous and can
cause severe burns and electric
shock that may result in death or
serious injury.
●Never touch, disassemble,
remove or replace the high volt-
age parts, cables or their con-
nectors.
●The hybrid system will become
hot after starting as the system
uses high voltage. Be careful of
both the high voltage and the
high temperature, and always
obey the warning labels
attached to the vehicle.
●Never try to open the service
plug access hole located under-
neath the console box. The ser-
vice plug is used only when the
vehicle is serviced and is sub-
ject to high voltage.
■Road accident cautions
Observe the following precautions
to reduce the risk of death or seri-
ous injury:
●Pull your vehicle off the road,
shift the shift le ver to P, apply
the parking brake, and turn the
hybrid system off.
●Do not touch the high voltage
parts, cables and connectors.
●If electric wires are exposed
inside or outside your vehicle,
an electric shock may occur.
Never touch exposed electric
wires.
●If a fluid leak occurs, do not
touch the fluid as it may be
strong alkaline electrolyte from
the hybrid battery (traction bat-
tery). If it comes into contact
with your skin or eyes, wash it
off immediately with a large
amount of water or, if possible,
boric acid solution. Seek imme-
diate medical attention.

851-4. Hybrid system
1
For safety and security
There are air intake vents under
the front seats for the purpose of
cooling the hybrid battery (trac-
tion battery). If the vent
becomes blocked, the hybrid
battery (traction battery) may
overheat, leading to a reduction
in hybrid battery (traction bat-
tery) output.
WARNING
●If a fire occurs in the hybrid
vehicle, leave the vehicle as
soon as possible. Never use a
fire extinguisher that is not
meant for electric fires. Using
even a small amount of water
may be dangerous.
●If your vehicle needs to be
towed, do so with four wheels
raised. If the wheels connected
to the electric motor (traction
motor) are on the ground when
towing, the motor may continue
to generate electricity. This may
cause a fire. ( P.462)
●Carefully inspect the ground
under the vehicle. If you find
that liquid has leaked onto the
ground, the fuel system may
have been damaged. Leave the
vehicle as soon as possible.
■Hybrid battery (traction bat-
tery)
●Never resell, hand over or mod-
ify the hybrid battery. To prevent
accidents, hybrid batteries that
have been removed from a dis-
posed vehicle are collected
through Toyota dealer. Do not
dispose of the battery yourself.
Unless the battery is properly col-
lected, the follo wing may occur,
resulting in dea th or serious
injury:
• The hybrid battery may be ille- gally disposed of or dumped,
and it is hazardous to the envi-
ronment or someone may touch
a high voltage part, resulting in
an electric shock.
• The hybrid battery is intended to be used exclusively with your
hybrid vehicle. If the hybrid bat-
tery is used out side of your
vehicle or modified in any way,
accidents such as electric
shock, heat generation, smoke
generation, an explosion and
electrolyte leakage may occur.
When reselling or handing over
your vehicle, the possibility of an
accident is extremely high
because the person receiving the
vehicle may not be aware of these
dangers.
●If your vehicle is disposed of
without the hybrid battery hav-
ing been removed, there is a
danger of serious electric shock
if high voltage parts, cables and
their connectors are touched. In
the event that your vehicle must
be disposed of, the hybrid bat-
tery must be disposed of by
your Toyota dealer or a qualified
service shop. If the hybrid bat-
tery is not disposed of properly,
it may cause electric shock that
can result in dea th or serious
injury.
Hybrid battery (traction
battery) air intake vents

2244-1. Before driving
*: The towing package is required.
Toyota does no t recommend tow-
ing with this vehicle without the tow-
ing package.
 The gross vehicle weight
must never exceed the
GVWR indicated on the Certi-
fication Label.
 The gross axle weight on
each axle must never exceed
the GAWR indicated on the
Certification Label.
 If the gross trailer weight is
over the unbraked TWR,
trailer service brakes are
required.
 If the gross trailer weight is
over 2000 lbs. (907 kg), a
sway control device with suffi-
cient capacity is required.
Confirm that the gross trailer
weight, gross combination
weight, gross vehicle weight,
gross axle weight and tongue
weight are all within the limits.
■GCWR*
2WD models
8818 lb. (4000 kg)
AWD models
8995 lb. (4080 kg)
*: This model meets the tow-vehicle trailering requirement of SAE
International per SAE J2807.
The towing package is required.
Toyota does not recommend tow-
ing with this vehicle without the tow-
ing package.
■TWR*
3500 lb. (1585 kg)
*: This model meets the tow-vehicle trailering requirement of SAE
International per SAE J2807.
The towing package is required.
Toyota does not recommend tow-
ing with this vehicle without the tow-
ing package.
■Unbraked TWR*
1000 lb. (450 kg)
*: This model meets the tow-vehicle trailering requirement of SAE
International per SAE J2807.
 A recommended tongue
weight varies in accordance
with the types of trailers or
towing as described below.
 To ensure the recommended
values shown below, the
trailer must be loaded by
referring to the following
GCWR, TWR and
Unbraked TWRTrailer Tongue Weight

3434-6. Driving tips
4
Driving
Use fluids that are appropriate
to the prevailing outside tem-
peratures.
• Engine oil
• Engine coolant
• Power control unit coolant
• Washer fluid
Have a service technician
inspect the condition of the
12-volt battery.
 Have the vehicle fitted with
four snow tires or purchase a
set of tire chains for the front
tires.
*
Ensure that all tires are the same
size and brand, and that chains
match the size of the tires.
*: Tire chains cannot be mounted
on vehicles with 20-inch tires.
Winter driving tips
Carry out the necessary
preparations and inspec-
tions before driving the
vehicle in winter. Always
drive the vehicle in a man-
ner appropriate to the pre-
vailing weather conditions.
Pre-winter preparations
WARNING
■Driving with snow tires
Observe the following precautions
to reduce the risk of accidents.
Failure to do so may result in a
loss of vehicle control and cause
death or serious injury.
●Use tires of the specified size.
●Maintain the recommended
level of air pressure.
●Do not drive in excess of 75
mph (120 km/h), regardless of
the type of snow tires being
used.
●Use snow tires on all, not just
some wheels.
■Driving with tire chains (vehi-
cles with 17-inch or 18-inch
tires)
Observe the following precautions
to reduce the risk of accidents.
Failure to do so may result in the
vehicle being unable to be driven
safely, and may cause death or
serious injury.
●Do not drive in excess of the
speed limit specifi ed for the tire
chains being used, or 30 mph
(50 km/h), whichever is lower.
●Avoid driving on bumpy road
surfaces or over potholes.
●Avoid sudden acceleration,
abrupt steering, sudden brak-
ing and shifting operations that
cause sudden engine braking.
●Slow down sufficiently before
entering a curve to ensure that
vehicle control is maintained.
●Do not use LTA (Lane Tracing
Assist) system.

3515-1. Using the air conditioning system and defogger
5
Interior features
switch.
■Operation of the air condition-
ing system in Eco drive mode
●In Eco drive mode, the air condi-
tioning system is controlled as fol-
lows to prioritize fuel efficiency:
• Engine speed and compressor operation controlled to restrict
heating/cooling capacity
• Fan speed restr icted when auto-
matic mode is selected
●To improve air conditioning perfor-
mance, perform the following
operations:
• Adjust the fan speed
• Turn off Eco drive mode ( P.333)
• Turn off Eco air conditioning mode
●When the driving mode is set to
Eco driving mode, the Eco air con-
ditioning mode will be turned on
automatically. Even in this case,
the Eco air conditioning mode can
be turned off by pressing the Eco
air conditioning mode switch.
■When the outside temperature
falls to nearly 32°F (0°C)
The dehumidification function may
not operate even when “A/C” switch
is pressed.
■Ventilation and air conditioning
odors
●To let fresh air in, set the air condi-
tioning system to the outside air
mode.
●During use, various odors from
inside and outside the vehicle may
enter into and a ccumulate in the
air conditioning system. This may
then cause odor to be emitted
from the vents.
●To reduce potential odors from
occurring:
• It is recommended that the air conditioning system be set to out-
side air mode prior to turning the
vehicle off.
• The start timing of the blower may
be delayed for a short period of
time immediately after the air con-
ditioning system is started in auto- matic mode.
●When parking, the system auto-
matically switches to outside air
mode to encourage better air cir-
culation throughout the vehicle,
helping to reduce odors that occur
when starting the vehicle.
■Air conditioning filter
 P.441
■Air conditioning system refrig-
erant
●A label regarding the refrigerant of
the air conditioning system is
attached to the h ood at the loca-
tion shown in the following illustra-
tion.
●The meaning of each symbol on
the label are as follows:
■Customization
Some functions can be customized.
Caution
Air conditioning sys-
tem
Air conditioning sys-
tem lubricant type
Requires registered
technician to service
air conditioning sys-
tem
Flammable refrigerant

399
6
6
Maintenance and care
Maintenance and care
6-1. Maintenance and careCleaning and protecting the vehicle exterior .......... 400
Cleaning and protecting the vehicle interior ........... 403
6-2. Maintenance Maintenance requirements.................................. 406
General maintenance.. 407
Emission inspection and maintenance (I/M) pro-
grams ........................ 410
6-3. Do-it-yourself mainte- nance
Do-it-yourself service pre- cautions ..................... 411
Hood ........................... 413
Positioning a floor jack 415
Engine compartment ... 416
12-volt battery ............. 422
Tires ............................ 424
Tire inflation pressure . 438
Wheels ......... ...............440
Air conditioning filter .... 441
Cleaning the hybrid battery (traction battery) air intake
vents and filters ......... 443
Electronic key battery.. 447
Checking and replacing fuses.......................... 449
Light bulbs................... 451

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

4076-2. Maintenance
6
Maintenance and care
You can perform some mainte-
nance procedures by yourself.
Please be aware that do-it-your-
self maintenance may affect
warranty coverage.
The use of Toyota Repair Manuals
is recommended.
For details about warranty cover-
age, refer to the separate “Owner’s
Warranty Information Booklet” or
“Owner’s Manual Supplement”.
Do-it-yourself mainte-
nanceGeneral 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.420)
Engine/power
control unit
coolant
Is the
engine/power con-
trol unit coolant at
the correct level?
( P.419)
Engine oil
Is the engine oil at
the correct level?
( P.416)