2021 TOYOTA TUNDRA ECU

511-1. For safe use
1
For safety and security
■Types of collisions that may not deploy the SRS airbags
(SRS side and curtain shield airbags)
The SRS side and curtain shield airbags may not activate if the vehicle is
subjected to a collision from the side at certain angles, or a collision to the
side of the vehicle body other than the passenger compartment.
The SRS side airbags do not generally inflate if the vehicle is involved in a
frontal or rear collision, if it rolls over, or if it is involv ed in a low-speed side
collision.
The SRS curtain shield airbags do not generally inflate if the vehicle is
involved in a rear collision, if it pitches end over end, or if it is involved in a
low-speed side or low-speed frontal collision. ● Collision from the side to the vehicle
body other than the passenger compart-
ment
● Collision from the side at an angle
● Collision from the front
● Collision from the rear
● Vehicle rollover
● Collision from the rear
● Pitching end over end

531-1. For safe use
1
For safety and security
Front passenger occupant classification
system
Your vehicle is equipped with a front passenger occupant classi -
fication system. This system det ects the conditions of the front
passenger seat and activates or deactivates the front passenger
airbag, front passenger knee airbag and front passenger’s seat
belt pretensioner.
Seat belt reminder light
SRS warning light
“AIR BAG OFF” indicator light
“AIR BAG ON” indicator light1
2
3
4

551-1. For safe use
1
For safety and security
■Unoccupied
■There is a malfunction in the system
*1: The system judges a person of adult size as an adult. When a smaller
adult sits in the front passenger seat, the system may recognize him/her
as a child depending on his/her physique and posture.
*2: In the event the front passenger is wearing a seat belt
*3: In the event the front passenger does not wear a seat belt
*4: When a larger child who has outgrown a child restraint system sits in the front passenger seat, the system may recognize him/her as an ad ult
depending on his/her physique or posture.
Indicator/
warning light
“AIR BAG ON” and “AIR BAG OFF”
indicator lightsNot illuminated
SRS warning light
Off
Front passenger’s seat belt reminder light
Devices
Front passenger airbag
Deactivated
Front passenger knee airbag
Front passenger’s seat belt pretensioner
Activated*7
or
deactivated
*8
Indicator/
warning light
“AIR BAG ON” and “AIR BAG OFF” indicator lights“AIR BAG OFF”
SRS warning light
On
Front passenger’s seat belt reminder light
Devices
Front passenger airbag
Deactivated
Front passenger knee airbag
Front passenger’s seat belt pretensionerActivated

571-1. For safe use
1
For safety and security
WARNING
■Front passenger occupant classification system precautions
● Do not recline the front passenger seatback so far that it touc hes a rear
seat. This may cause the “AIR BAG OFF” indicator light to be il luminated,
which indicates that the SRS airbags for the front passenger wi ll not acti-
vate in the event of a severe accident. If the seatback touches the rear
seat, return the seatback to a position where it does not touch the rear
seat. Keep the front passenger seatback as upright as possible when the
vehicle is moving. Reclining the seatback excessively may lesse n the
effectiveness of the seat belt system.
● If an adult sits in the front passenger seat, the “AIR BAG ON” indicator
light is illuminated. If the “AIR BAG OFF” indicator is illuminated, ask the
passenger to sit up straight, well back in the seat, feet on the floor, and
with the seat belt worn correctly. If the “AIR BAG OFF” indicat or still
remains illuminated, either ask the passenger to move to the re ar seat, or
if that is not possible, move the front passenger seat fully re arward.
● When it is unavoidable to install a forward-facing child restra int system on
the front passenger seat, install the child restraint system on the front pas-
senger seat in the proper order. ( P. 63)
● Do not modify or remove the front seats.
● Do not kick the front passenger seat or subject it to severe im pact. Other-
wise, the SRS warning light may come on to indicate a malfuncti on of the
front passenger occupant classification system. In this case, contact your
Toyota dealer immediately.
● Child restraint systems installed on the rear seat should not c ontact the
front seatbacks.
● Do not use a seat accessory, such as a cushion and seat cover, that cov-
ers the seat cushion surface.
● Do not attach a commercial seatback table or other heavy item t o the back
of the front passenger seat.
● Do not modify or replace the upholstery of the front seat.

591-1. For safe use
1
For safety and security
Child restraint systems
Studies have shown that installing a child restraint on a rear seat is
much safer than installing one on the front passenger seat.
● Choose a child restraint system that suits your vehicle and is appro-
priate to the age and size of the child.
● For installation details, follow the instructions provided with the child
restraint system.
General installation instructio ns are provided in this manual.
(  P. 63)
A child restraint system for a small child or baby must itself be
properly restrained on the seat with the lap portion of the lap /
shoulder belt.
The laws of all 50 states of th e U.S.A. and Canada now require
the use of child restraint systems.
Points to remember

611-1. For safe use
1
For safety and security
WARNING
■Child restraint precautions
● For effective protection in automobile accidents and sudden sto ps, a child
must be properly restrained, using a seat belt or child restrai nt system
depending on the age and size of the child. Holding a child in your arms is
not a substitute for a child restraint system. In an accident, the child can be
crushed against the windshield, or between you and the vehicle’ s interior.
● Toyota strongly urges the use of a proper child restraint syste m that con-
forms to the size of the child, installed on the rear seat. According to acci-
dent statistics, the child is safer when properly restrained in the rear seat
than in the front seat.
● Never install a rear-facing child restraint system on the front passenger
seat even if the “AIR BAG OFF” i ndicator light is illuminated.
In the event of an accident, the force of the rapid inflation o f the front pas-
senger airbag can cause death or serious injury to the child if the rear-fac-
ing child restraint system is installed on the front passenger seat.
● A forward-facing child restraint system may be installed on the front pas-
senger seat only when it is unavoidable. A child restraint system that
requires a top tether strap should not be used in the front passenger seat
since there is no top tether strap anchor for the front passenger seat.
Adjust the seatback as upright as possible and always move the seat as
far back as possible even if the “AIR BAG OFF” indicator light is illumi-
nated, because the front passenger airbag could inflate with considerable
speed and force. Otherwise, the child may be killed or seriously injured.

621-1. For safe use
WARNING
■Child restraint precautions
● Do not use the seat belt extender when installing a child restr aint system
on the front or rear passenger seat. If installing a child rest raint system
with the seat belt extender connected to the seat belt, the seat belt will not
securely hold the child restraint system, which could cause dea th or seri-
ous injury to the child or other passengers in the event of an accident.
● Do not allow the child to lean his/her head or any part of his/ her body
against the door or the area of the seat, front and rear pillar s or roof side
rails from which the SRS side airbags or SRS curtain shield air bags deploy
even if the child is seated in the child restraint system. It is dangerous if
the SRS side airbags and curtain shield airbags inflate, and th e impact
could cause death or serious injury to the child.
● Make sure you have complied with all installation instructions provided by
the child restraint manufacturer and that the system is properl y secured. If
it is not secured properly, it may cause death or serious injury to the child
in the event of a sudden stop or an accident.
■ When children are in the vehicle
Do not allow children to play with the seat belt. If the seat belt becomes
twisted around a child’s neck, it may lead to choking or other serious injuries
that could result in death.
If this occurs and the buckle cannot be unfastened, scissors sh ould be used
to cut the belt.
■ When the child restraint system is not in use
● Keep the child restraint system properly secured on the seat ev en if it is
not in use. Do not store the child restraint system unsecured in the pas-
senger compartment.
● If it is necessary to detach the child restraint system, remove it from the
vehicle. This will prevent it from injuring passengers in the event of a sud-
den stop or an accident.

631-1. For safe use
1
For safety and security
Installing child restraints
Double Cab models
Child restraint LATCH anchors
LATCH anchors are provided for
the outer rear seats. (Buttons dis-
playing the location of the anchors
are attached to the seats.)
Seat belts equipped with a child
restraint locking mechanism
(ALR/ELR belts except driver’s
seat belt) ( P. 36)
Anchor bracket (for top tether
strap)
An anchor bracket is provided on
each rear seat.
Follow the child restraint system manufacturer’s instructions.
Firmly secure child restraints to the seats using the LATCH
anchors or a seat belt. Attach t he top tether strap when installing
a child restraint.
The lap/shoulder belt can be used if your child restraint syste m
is not compatible with the LATCH (Lower Anchors and Tethers
for Children) system.