ECU TOYOTA SIENNA HYBRID 2021 (in English) User Guide

431-1. For safe use
1
For safety and security
Side impact sensors (rear)
Driver’s seat belt buckle switch
Driver’s seat position sensor
Driver airbag
Front passenger occupant classification sensors
Driver’s knee airbag
SRS warning light
Airbag sensor assembly
Your vehicle is equipped with ADVANCED AIRBAGS designed
based on the US motor vehicle safety standards (FMVSS208). The
airbag sensor assembly (ECU) cont rols airbag deployment based on
information obtained from the sensors etc. shown in the system
components diagram above. This in formation includes crash sever-
ity and occupant information. As the airbags deploy, a chemical
reaction in the inflators quickly fills the airbags with non-toxic gas to
help restrain the motion of the occupants.
■If the SRS airbags deploy
(inflate)
●Slight abrasions, burns, bruising
etc., may be sustained from SRS
airbags, due to the extremely high
speed deployment (inflation) by
hot gases.
●A loud noise and white powder will
be emitted.
●Parts of the airbag module (steer-
ing wheel hub, airbag cover and
inflator) as well as the front seats,
parts of the front and rear pillars,
and roof side rails, may be hot for
several minutes. T he airbag itself
may also be hot.
●The windshield may crack.
●The hybrid system will be stopped
and fuel supply to the engine will
be stopped. ( P.86)
●All of the doors will be unlocked
(  P.134)
●The brakes and st op lights will be
controlled automatically. (
 P.336)
●The interior lights will turn on auto-
matically. ( P.365)
●The emergency flashers will turn
on automatically. ( P.458)
●For Safety Connect subscribers, if
any of the following situations
occur, the system is designed to
send an emergency call to the
response center, notifying them of
the vehicle’s location (without
needing to push the “SOS” button)
and an agent will attempt to speak
with the occupants to ascertain
the level of emergency and assis-
tance required. If the occupants
are unable to communicate, the
agent automatically treats the call
as an emergency and helps to dis-
patch the necessary emergency
services. ( P.75)
• An SRS airbag is deployed.
• A seat belt pretensioner is acti- vated.
• The vehicle is involved in a severe rear-end collision.
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451-1. For safe use
1
For safety and security
■Types of collisions that may not
deploy the SRS airbags (SRS
front airbags)
The SRS front airbags do not gener-
ally inflate if the vehicle is involved
in a side or rear co llision, if it rolls
over, or if it is involved in a low-
speed frontal collision. But, when-
ever a collision of any type causes
sufficient forward deceleration of the
vehicle, deployment of the SRS
front airbags may occur.
●Collision from the side
●Collision from the rear
●Vehicle rollover
■Types of collisions that may not
deploy the SRS airbags (SRS
side and curtain shield airbags)
The SRS side and curtain shield air-
bags may not activate if the vehicle
is subjected to a c ollision from the
side at certain angl es, or a collision
to the side of the vehicle body other
than the passenger compartment.
●Collision from the s ide to the vehi-
cle body other than the passenger
compartment
●Collision from the s ide at an angleThe SRS side airbags do not gener-
ally inflate if the vehicle is involved
in a frontal or rear co
llision, if it rolls
over, or if it is involved in a low-
speed side collision.
●Collision from the front
●Collision from the rear
●Vehicle rollover
The SRS curtain sh ield airbags do
not generally inflate if the vehicle is
involved in a rear collision, if it
pitches end over en d, or if it is
involved in a low- speed side or low-
speed frontal collision.
●Collision from the rear
●Pitching end over end
■When to contact your Toyota
dealer
In the following ca ses, the vehicle
will require inspectio n and/or repair.
Contact your Toyota dealer as soon
as possible.
●Any of the SRS airbags have

471-1. For safe use
1
For safety and security
WARNING
●The SRS driver airbag deploys
with considerable force, and
can cause death or serious
injury especially i f the driver is
very close to the airbag. The
National Highway Traffic Safety
Administration (NHTSA)
advises: Since the risk zone for
the driver’s airbag is the first 2 -
3 in. (50 - 75 mm) of inflation,
placing yourself 10 in. (250 mm)
from your driver airbag provides
you with a clear margin of
safety. This distance is mea-
sured from the center of the
steering wheel to your breast-
bone. If you sit less than 10 in.
(250 mm) away now, you can
change your driving position in
several ways:
• Move your seat to the rear as far as you can while still reach-
ing the pedals comfortably.
• Slightly recline the back of the seat.
Although vehicle designs vary,
many drivers can achieve the
10 in. (250 mm) distance, even
with the driver seat all the way
forward, simply by reclining the
back of the seat somewhat. If
reclining the back of your seat
makes it hard to see the road,
raise yourself by using a firm,
non-slippery cushion, or raise
the seat if your vehicle has that
feature.
• If your steering wheel is adjust- able, tilt it downward. This
points the airbag toward your
chest instead of your head and
neck.
The seat should be adjusted as
recommended by NHTSA above,
while still maintaining control of
the foot pedals, steering wheel,
and your view of the instrument
panel controls.
●If the seat belt extender has
been connected to the front
seat belt buckles but the seat
belt extender has not also been
fastened to the latch plate of the
seat belt, the SRS front airbags
will judge that the driver and
front passenger are wearing the
seat belt even though the seat
belt has not been connected. In
this case, the SRS front airbags
may not activate correctly in a
collision, resulting in death or
serious injury in the event of a
collision. Be su re to wear the
seat belt with the seat belt
extender.
●The SRS front passenger air-
bag also deploys with consider-
able force, and can cause death
or serious injury especially if the
front passenger is very close to
the airbag. The front passenger
seat should be as far from the
airbag as possible with the seat-
back adjusted, so the front pas-
senger sits upright.
●Improperly seated and/or
restrained infants and children
can be killed or seriously injured
by a deploying airbag. An infant
or child who is too small to use
a seat belt should be properly
secured using a child restraint
system. Toyota strongly recom-
mends that all infants and chil-
dren be placed in the rear seats
of the vehicle and properly
restrained. The rear seats are
safer for infants and children
than the front passenger seat.
(  P.58)

491-1. For safe use
1
For safety and security
WARNING
●Do not hang coat hangers or
other hard objects on the coat
hooks. All of these items could
become projectiles and may
cause death or serious injury,
should the SRS curtain shield
airbags deploy.
●If a vinyl cover is put on the area
where the SRS knee airbag will
deploy, be sure to remove it.
●Do not use seat accessories
which cover the parts where the
SRS side airbags and SRS seat
cushion airbag inflate as they
may interfere with inflation of
the SRS airbags. Such acces-
sories may prevent the SRS
side airbags and SRS seat
cushion airbag from activating
correctly, disable the system or
cause the SRS side airbags and
SRS seat cushion airbag to
inflate accidentally, resulting in
death or serious injury.
●Do not strike or apply significant
levels of force to the area of the
SRS airbag components or the
front doors.
Doing so can cause the SRS
airbags to malfunction.
●Do not touch any of the compo-
nent parts immediately after the
SRS airbags have deployed
(inflated) as they may be hot.
●If breathing becomes difficult
after the SRS airbags have
deployed, open a door or side
window to allow fresh air in, or
leave the vehicle if it is safe to
do so. Wash off any residue as
soon as possible to prevent skin
irritation.
●If the areas where the SRS air-
bags are stored, such as the
steering wheel pad and front
and rear pillar garnishes, are
damaged or cracked, have
them replaced by your Toyota
dealer.
●Do not place anything, such as
a cushion, on the front passen-
ger’s seat. Doing so will
disperse the passenger’s
weight, which prevents the sen-
sor from detecting the passen-
ger’s weight properly. As a
result, the SRS front airbags for
the front passenger may not
deploy in the event of a colli-
sion.
■Modification and disposal of
SRS airbag system compo-
nents
Do not dispose of your vehicle or
perform any of the following modi-
fications without consulting your
Toyota dealer. The SRS airbags
may malfunction or deploy
(inflate) accidentally, causing
death or serious injury.
●Installation, re moval, disassem-
bly and repair of the SRS air-
bags
●Repairs, modific ations, removal
or replacement of the steering
wheel, instrument panel, dash-
board, seats or seat upholstery,
front, side and rear pillars, roof
side rails, front door panels,
front door trims or front door
speakers
●Modifications to the front door
panel (such as making a hole in
it)
●Repairs or modifications of the
front fender, fr ont bumper, or
side of the occupant compart-
ment

511-1. For safe use
1
For safety and security
SRS warning light
Seat belt reminder light
“AIR BAG OFF” indicator light
“AIR BAG ON” indicator light
Front passenger occupant classification system
Your vehicle is equipped with a front passenger occupant
classification system. This system detects the conditions of
the front passenger seat and activates or deactivates the front
passenger airbag and seat cushion airbag in the front passen-
ger side.
System components
A
B
C
D
:$51,1*
■Front passenger occupant
classification system precau-
tions
Observe the following precautions
regarding the front passenger
occupant classification system.
Failure to do so may cause death
or serious injury.
●Wear the seat belt properly.
●Make sure the front passenger’s
seat belt plate has not been left
inserted into the buckle before
someone sits in the front pas-
senger seat.

531-1. For safe use
1
For safety and security
■Adult*1
■Child*4
WARNING
●Child restraint systems installed
on the rear seat should not con-
tact the front seatbacks.
●Do not use a seat accessory,
such as a cushion and seat
cover, that covers the seat
cushion surface.
●Do not modify or replace the
upholstery of the front seat.
Condition and operation in th e front passenger occupant
classification system
Indicators/warn- ing lights
“AIR BAG ON” and “AIR BAG OFF” indicator lights“AIR BAG ON”
SRS warning lightOff
Seat belt reminder lightOff*2 or flashing*3
Devices
Front passenger airbagActivated
Front passenger’s seat cushion air- bagActivated *2 or
deactivated
*3
Indicators/warn- ing lights
“AIR BAG ON” and “AIR BAG OFF” indicator lights“AIR BAG OFF” or “AIR BAG
ON”
*4
SRS warning lightOff
Seat belt reminder lightOff*2 or flashing*3
Devices
Front passenger airbagDeactivated or activated
*4
Front passenger’s seat cushion air- bagDeactivated or
activated
*2, 4

551-1. For safe use
1
For safety and security
*5: Never install a rear-facing child restraint system on the front passenger
seat. A forward-facing child res traint system should only be installed on
the front passenger sea t when it is unavoidable. ( P.61)
*6: In case the indicator light is not illuminated, consult this m anual on how
to install the child restr aint system properly. (P.58)

571-2. Child safety
1
For safety and security
1-2.Child safety
Riding with children
Observe the following pre-
cautions when children are
in the vehicle.
Use a child restraint system
appropriate for the child,
until the child becomes
large enough to properly
wear the vehicle’s seat belt.
It is recommended that chil-
dren sit in the rear seats to
avoid accidental contact
with the shift lever, wiper
switch, etc.
 Use the sliding door child-
protector lock or the window
lock switch to avoid children
opening the door while driv-
ing or operating the power
window accidentally.
( P.142, 203)
 Do not let small children
operate equipment which
may catch or pinch body
parts, such as the power
window, hood, back door,
seats, etc.
WARNING
■When children are in the vehi-
cle
Never leave children unattended
in the vehicle, and never allow
children to have or use the key.
Children may be able to start the
vehicle or shift the vehicle into
neutral. There is also a danger
that children ma y injure them-
selves by playing with the side
windows, the moon roof (if
equipped) or other features of the
vehicle. In addition, heat build-up
or extremely cold temperatures
inside the vehicle can be fatal to
children.

591-2. Child safety
1
For safety and security
WARNING
●Toyota strongly urges the use of
a proper child restraint system
that conforms to the weight and
size of the child, installed on the
rear seat. According to accident
statistics, the child is safer when
properly restrained in the rear
seat than in the front seat.
●Holding a child in your or some-
one else’s arms is not a substi-
tute for a child restraint system.
In an accident, the child can be
crushed against the windshield
or between the holder and the
interior of the vehicle.
■Handling the child restraint
system
If the child restraint system is not
properly fixed in place, the child or
other passengers may be seri-
ously injured or even killed in the
event of sudden braking, sudden
swerving, or an accident.
●If the vehicle were to receive a
strong impact from an accident,
etc., it is possib le that the child
restraint system has damage
that is not readily visible. In
such cases, do not reuse the
restraint system.
●Make sure you have complied
with all installation instructions
provided by the child restraint
system manufacturer and that
the system is properly secured.
●Keep the child restraint system
properly secured on the seat
even if it is not in use. Do not
store the child restraint system
unsecured in the passenger
compartment.
●If it is necessa ry to detach the
child restraint system, remove it
from the vehicle or store it
securely in the luggage com-
partment.

611-2. Child safety
1
For safety and security
■When installing a child
restraint system to a front
passenger seat
For the safety of a child, install a
child restraint system to a rear seat. When installing the child
restraint system to a front pas-
senger seat is unavoidable,
adjust the seat as follows and
install the child restraint system.

Raise the seatback as much
as possible.
 Move the front seat fully rear-
Anchor brackets (for
top tether strap) attach- ment
Second seats (8-pas senger models):
Second seats (7-pas senger models):
Third seats:
P.71
Installation methodPage
When using a child
restraint system