2021 TOYOTA SIENNA HYBRID Owners Manual (in English)

811-4. Hybrid system
1
For safety and security
hybrid system, contact your Toyota
dealer.
■Charging the 12-volt battery
 P.508
■After the 12-volt battery has dis-
charged or when the terminal
has been removed and installed
during exchange, etc.
The gasoline engine may not stop
even if the vehicle is being driven by
the hybrid battery (traction battery).
If this continues for a few days, con-
tact your To yota dealer.
■Sounds and vibrations specific
to a hybrid vehicle
There may be no engine sound or
vibration even though the vehicle is
able to move with the “READY” indi-
cator is illuminate d. For safety,
make sure to shift the shift lever to P
and apply the parking brake when
parked.
The following sounds or vibrations
may occur when the hybrid system
is operating and are not a malfunc-
tion:
●Motor sounds may be heard from
the engine compartment.
●Sounds may be heard from the
hybrid battery (traction battery)
under the front seats when the
hybrid system starts or stops.
●Relay operating sounds such as a
snap or soft clank will be emitted
from the hybrid battery (traction
battery), under the front seats,
when the hybrid system is started
or stopped.
●Sounds from the hybrid system
may be heard when the back door
is open.
●Sounds may be heard from the
transmission when the gasoline
engine starts or stops, when driv-
ing at low speeds, or during idling.
●Engine sounds may be heard
when accelerating sharply.
●Sounds may be heard due to regenerative braking when the
brake pedal is depressed or as
the accelerator pedal is released.
●Vibration may be felt when the
gasoline engine starts or stops.
●Cooling fan sounds may be heard
from the air intake vent under the
front seat.
■Maintenance, repair, recycling,
and disposal
Contact your Toyota dealer regard-
ing maintenance, repair, recycling
and disposal. Do n ot dispose of the
vehicle yourself.
When driving with the gasoline
engine stopped, a sound, which
changes in accordance with the
driving speed, will be played in
order to warn people nearby of
the vehicle’s approach. The
sound will stop when the vehicle
speed exceeds approximately
22 mph (35 km/h).
■Acoustic Vehicle Alerting Sys-
tem
In the following cases, the Acoustic
Vehicle Alerting System may be dif-
ficult for surrounding people to hear.
●In very noisy areas
●In the wind or the rain
■If “Acoustic Vehicle Alerting
System Malfunction Visit Your
Dealer” is displayed on the
multi-information display
The system may be malfunctioning.
Have the vehicle inspected by your
Toyota dealer.
Acoustic Vehicle Alerting
System

821-4. Hybrid system
*: This function can only be used in
the mainland U.S.A. It cannot be
used in other states and territo-
ries, including Alaska and Hawaii.
This system operates based on
the driving situation and traffic
information to enhance fuel
economy.
For details about Predictive effi-
cient drive, refer to “NAVIGA-
TION AND MULTIMEDIA
SYSTEM OWNER’S MANUAL”.
■Predictive deceleration sup-
port
 When the vehicle approaches
to predictive deceleration sup-
port points registered in the
navigation system, the “Refer-
ence operation range” ( ) of
the ECO Accelerator Guid-
ance ( P.108) on the multi-
information display will be
turned off to encourage the
driver to reduce excessive
acceleration.
 The engine braking force will be increased according to the
driving conditions to more effi-
ciently charge the hybrid bat-
tery (traction battery) after the
accelerator pedal is released.
■Predictive SOC control
The following types of control
are performed based on data
such as road and traffic informa-
tion during route guidance by
the navigation system to help
ensure that the vehicle effi-
ciently uses electricity.
 When there is a long downhill
slope along the route, the sys-
tem reduces the hybrid bat-
tery (traction battery) level
before reaching the slope to
help ensure charging capacity
for regenerative braking while
traveling downhill.
 When traffic congestion is
predicted along the route, the
system helps ensure a certain
battery level before reaching
congested roads to reduce
the frequency of starting the
engine to charge the hybrid
battery (traction battery) due
to low battery levels.
Predictive efficient drive
(vehicles with navigation
system)
*
A

831-4. Hybrid system
1
For safety and security
The illustration is an example for explanation and may differ from the actual
item.
Warning label
Service plug
Rear electric motor (traction motor)
*
Hybrid battery (traction battery)
High voltage cables (orange)
Front electric motor (traction motor)
Power control unit
Air conditioning compressor
*: AWD models only
Hybrid system precautions
Take care when handling the hybrid system, as it is a high
voltage system (about 650V at maximum) as well as contains
parts that become extremely hot when the hybrid system is
operating. Obey the warning labels attached to the vehicle.
System components
A
B
C
D
E
F
G
H

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

861-4. Hybrid system
When a certain level of impact is
detected by the impact sensor,
the emergency shut off system
blocks the high voltage current
and stops the fuel pump to mini-
mize the risk of electrocution
and fuel leakage. If the emer-
gency shut off system activates,
your vehicle will not restart. To
restart the hybrid system, con-
tact your Toyota dealer.
A message is automatically dis-
played when a malfunction
occurs in the hybrid system or
an improper operation is
attempted.
If a warning message is shown
on the multi-information display,
read the message and follow the
NOTICE
■Hybrid battery (traction bat-
tery) air intake vents
●Make sure not to block the air
intake vents with anything, such
as a seat cover, plastic cover, or
luggage. If the vents become
blocked, the hybrid battery
(traction battery) input and out-
put may be restricted, leading to
a reduction in hybrid battery
(traction battery) output and a
malfunction.
●When dust etc. has accumu-
lated in the air intake vents,
clean them with a vacuum
cleaner to prevent the vents
from clogging.
●Do not get water or foreign
materials in the air intake vents
as this may cause a short circuit
and damage the hybrid battery
(traction battery).
●Do not carry large amounts of
water such as water cooler bot-
tles in the vehicle. If water spills
onto the hybrid battery (traction
battery), the battery may be
damaged. Have the vehicle
inspected by your Toyota
dealer.
●There are filters installed to the
air intake vents. When the filters
remain noticeably dirty even
after cleaning the air intake
vents, filters cleaning or
replacement is recommended.
For information regarding filters
cleaning or replacement, refer
to P.444.
●If “Maintenance Required for
Traction Battery Cooling Parts
See Owner’s Manual” is shown
on the multi-information dis-
play, the air intake vents and fil-
ters may be clogged. Refer to
P.443for information on how to
clean the air intake vents.
Emergency shut off sys-
tem
Hybrid warning message

871-4. Hybrid system
1
For safety and security
instructions.
■If a warning light comes on, a
warning message is displayed,
or the 12-volt battery is discon-
nected
The hybrid system may not start. In
this case, try to start the system
again. If the “READY” indicator does
not come on, contact your Toyota
dealer.

881-5. Theft deterrent system
1-5.Theft deterrent system
The indicator light flashes after
the power switch has been
turned to OFF to indicate that
the system is operating.
The indicator light stops flashing
after the power switch has been
turned to ACC or ON to indicate
that the system has been can-
celed.
■System maintenance
The vehicle has a maintenance-free
type immobilizer system.
■Conditions that may cause the
system to malfunction
●If the grip portion of the key is in
contact with a metallic object
●If the key is in close proximity to or
touching a key to the security sys-
tem (key with a built-in transpon-
der chip) of another vehicle
Immobilizer system
The vehicle’s keys have
built-in transponder chips
that prevent the hybrid sys-
tem from starting if a key
has not been previously
registered in the vehicle’s
on-board computer.
Never leave the keys inside
the vehicle when you leave
the vehicle.
This system is designed to
help prevent vehicle theft but
does not guarantee absolute
security against all vehicle
thefts.
Operating the system
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.