2023 SUBARU BRZ sensor

Seatbelt Pretensioners
45
Seat, Seatbelt and SRS Airbags1
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When you sell your vehicle, we urge
you to inform the bu yer that the vehicle
is equipped with seatbelt
pretensioners. Also, notify the buyer of
the contents in this section.■ Front seatbelt with Shoulder
Belt PretensionerThe pretensioner sensor also serves as
follows.
 Front impact sensor
 Side impact sensor
 Rollover sensor
If the sensor detects a certain predeter-
mined amount of force during frontal or
side collisions or rollover accidents, any
seatbelt that has a se atbelt pretensioner is
quickly drawn back in by the retractor to take up the slack so
that the belt more
effectively restrains the seat occupant.
The front seatbelt pretensioner includes a
tension reducing device which limits the
peak forces exerted by the seatbelt on the
occupant in the event of a collision. The
front passenger's side adaptive force
limiter will select a reducing load to suit the
body size of the occupant as detected by
the occupant detection sensor.
When a seatbelt pretensioner is activated,
an operating noise will be heard and a
small amount of smoke will be released.
These occurrences are normal and not
harmful. This smoke does not indicate a
fire in the vehicle.
Once the seatbelt pretensioner has been
activated, the seatbelt retractor remains
locked. Consequently, the seatbelt cannot
be pulled out and retracted and therefore
must be replaced.
■ System MonitorsA diagnostic system continually monitors
the readiness of the seatbelt pretensioner
with the ignition switch in the “ON” posi-
tion. The seatbelt pr etensioners share the
control module with the SRS airbag
system. Therefore, if any malfunction
occurs in a seatbelt pretensioner, the SRS
airbag system warning light will illuminate. For details, refer to "SRS Airbag System

Monitors" P87.
■ System Servicing
100121
WARNING
When discarding a seatbelt
retractor assembly or scrapping
the entire vehicle damaged by a
collision, consult your SUBARU
dealer. Tampering with or disconnecting
the system’s wiring could result
in accidental activation of the
seatbelt pretensioner and/or SRS
airbag or could make the system
inoperative, which may result in
serious injury. Do not use elec-
trical test equipment on any
circuit related to the seatbelt
pretensioner and SRS airbag
systems. For required servicing
of the seatbelt pretensioner,
consult your nearest SUBARU
dealer.
CAUTION
For the locations of the sensors and
control modules, refer to "Compo-
nents" P68.
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SRS Airbag (Supplemental Restraint System Airbag)
69
Seat, Seatbelt and SRS Airbags1
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4
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21
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1) Front impact sensor (left-hand side)
2) Front impact sensor (right-hand side)
3) SRS airbag system warning light
4) Frontal airbag module (driver’s side)
5) Airbag control module (including impact
sensor and rollover sensor)
6) Front passenger’s frontal airbag ON
and OFF indicator
7) Frontal airbag module (front
passenger’s side)
8) Seatbelt buckle switch (front
passenger’s side)
9) Curtain airbag module (right-hand side)
10) Side impact sensor (door right-hand
side)
11) Side airbag module (front passenger’s
side)
12) Seatbelt pretensioner and adaptive
force limiter (front passenger’s side)
13) Side impact sensor (center pillar right-
hand side)
14) Airbag wiring
15) Side impact sensor (rear wheel house
right-hand side)
16) Front passenger’s occupant detection
sensors
17) Side impact sensor (rear wheel house
left-hand side)
18) Side airbag module (driver’s side)
19) Side impact sensor (center pillar left-
hand side)
20) Seatbelt pretensi oner (driver’s side)
21) Side impact sensor (door left-hand side)
22) Knee airbag module (driver’s side)
23) Curtain airbag module (left-hand side)
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SRS Airbag (Supplemental Restraint System Airbag)
71
Seat, Seatbelt and SRS Airbags1
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▼Front passenger’s SRS frontal
airbagThe front passenger’s SRS frontal airbag
uses a dual stage inflator. The inflator
operates in different ways depending on
the severity of impact.1) Occupant detection sensorsThe occupant detection sensors are
installed between the seat and seat rails,
and monitor the physique and posture of
the front passenger. Using this informa-
tion, the occupant detection system deter-
mines whether the front passenger’s SRS
frontal airbag should be deployed or not.
The occupant detect ion system may not
inflate the front passenger’s SRS frontal
airbag even when the driver’s SRS frontal
airbag deploys. This is normal. In this
case, although the front passenger’s SRS frontal airbag does not operate, the front

passenger’s seatbelt pretensioner oper-
ates with the driver’s seatbelt
pretensioner. For details about the
seatbelt pretensioner, refer to "Seatbelt
Pretensioners" P44.
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1
CAUTION
Observe the following precautions.
Failure to do so may prevent the
SUBARU advanced frontal airbag
system from functioning correctly
or cause the system to fail. Do not apply any strong impact to
the front passenger’s seat such
as by kicking. Do not let rear passengers rest
their feet between the front
seatback and seat cushion. Do not remove or disassemble
the front passenger’s seat. Do not install any accessory
(such as an audio amplifier) other
than a genuine SUBARU acces-
sory under the front passenger’s
seat. Do not place anything (shoes,
umbrella, etc.) under the front
passenger’s seat.
 Do not place any objects (books,
etc.) around the front
passenger’s seat. Do not use the front passenger’s
seat with the head restraint
removed. Do not leave any articles on the
front passenger’s seat or the
seatbelt tongue and buckle
engaged when you leave your
vehicle. Do not put sharp object(s) on the
seat or pierce the seat uphol-
stery. Do not place a magnet near the
seatbelt buckle and the seatbelt
retractor. Do not use front seats with their
backward-forward position and
seatback not being locked into
place securely. If any of them are
not locked securely, adjust them
again. For adjusting procedure,
refer to "Manual Seat" P33
(models equipped with manual
seats only).
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SRS Airbag (Supplemental Restraint System Airbag)
72SRS airbag system warning lightIf the seatbelt buckle switch and/or front
passenger’s occupant detection system
have failed, the SRS airbag system
warning light will illuminate. Have the
system inspected by your SUBARU
dealer immediately if the SRS airbag
system warning light illuminates.
If your vehicle has sustained impact, this
may affect the proper function of the
SUBARU advanced frontal airbag system.
If the SRS airbag system warning light illu-
minates, immediately stop the vehicle in a
safe place, and consult a SUBARU
dealer.
▼ Passenger’s frontal airbag ON and
OFF indicators
: Front passenger’s frontal airbag ON
indicator
: Front passenger’s frontal airbag
OFF indicator
Refer to "Front Passenger’s Frontal
Airbag ON and OFF Indicators" P135. ▼
Occupant detection system
1) Occupant detection sensorsThe occupant detection sensors are
installed between the seat and seat rails,
and monitor the physique and posture of
the front passenger. Using this informa-
tion, the occupant det ection system deter-
mines whether the front passenger’s SRS
frontal airbag should be deployed or not.
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SRS Airbag (Supplemental Restraint System Airbag)
76▼Operation
101586
A
B
1
2
A) Driver’s side
B) Passenger’s side
1) SRS AIRBAGs deploy as soon as a
collision occurs.
2) After deployment, SRS AIRBAGs start
to deflate immediately so that the
driver’s vision is not obstructed.The SRS airbags can function only when
the ignition switch is in the “ON” position.
The SUBARU advanced frontal airbag
system is designed to determine the acti-
vation or deactivation condition of the front
passenger’s SRS frontal airbag
depending on the characteristic of item(s)
or person on the front passenger’s seat
monitored by the front passenger’s occu-
pant detection sensors. For this reason,
only the driver’s SRS frontal airbag may
deploy in the event of a collision, but this
does not mean failure of the system.
If the following sensors detect a predeter-
mined amount of force during a frontal
collision, the control module sends signals
to the airbag module(s) (only driver’s
module or both driver’s and front
passenger’s modules) instructing the
module(s) to inflate the SRS frontal
airbag(s).
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SRS Airbag (Supplemental Restraint System Airbag)
77
Seat, Seatbelt and SRS Airbags1
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The front impact sensors
 The impact sensors in the airbag
control module
On the driver’s side, the SRS knee airbag
also inflates with the SRS frontal airbag.
The driver’s and front passenger’s SRS
frontal airbags use dual stage inflators.
The two inflators of each airbag are trig-
gered either sequentially or simultane-
ously, depending on the severity of
impact, in the case of the driver’s SRS
frontal airbag and depending on the
severity of impact and the characteristic of
item(s) or person on the seat in the case
of the front passenger’s SRS frontal
airbag.▼ After deployment
After deployment, the SRS airbag immedi-
ately starts to deflate so that the driver’s
vision is not obstructed and the driver’s
ability to maintain control of the vehicle is
not impaired. The time required from
detecting impact to the deflation of the
SRS airbag after deployment is shorter
than the blink of an eye.
Both when only the driver’s SRS frontal
airbag deploys and the driver’s and front
passenger’s SRS frontal airbags deploy,
the driver’s and front passenger’s seatbelt
pretensioners operate at the same time. When the SRS airbag deploys, a sudden,

fairly loud inflation noise will be heard and
some smoke will be released. These
occurrences are a normal result of the
deployment. This smoke does not indicate
a fire in the vehicle.
▼ Example of the type of accident
The driver’s SRS frontal airbag and front
passenger’s SRS frontal airbag are
designed as follows.
 To deploy in the event of an accident
involving a moderate to severe frontal
collision
 To function on a one-time-only basis
The driver’s SRS frontal airbag and front
passenger’s SRS frontal airbag are not
designed as follows.
 To deploy in most lesser frontal
impacts
*1
 To deploy in most side or rear impacts
or in most rollover accidents
*2
*1: Because the necessary protection can be
achieved by the seatbelt alone.
*2: Because deployment of only the driver’s
SRS frontal airbag or both the driver’s and
front passenger’s SRS frontal airbags would
not protect the occupant in those situations.SRS airbag deployment depends on the
level of force experienced in the
passenger compartment during a colli-
sion. That level differs from one type of
collision to another, and it may have no
bearing on the visible damage done to the
vehicle itself.
CAUTION
Do not touch the SRS airbag system
components around the steering
wheel and dashboard with bare
hands right after deployment. Doing
so can cause burns because the
components can be very hot as a
result of deployment.
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SRS Airbag (Supplemental Restraint System Airbag)
81
Seat, Seatbelt and SRS Airbags1
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▼SRS curtain airbag
Your vehicle is equipped with a SUBARU
SRS curtain airbag system that complies
with the Federal Motor Vehicle Safety
Standard (FMVSS) No. 226.
The SRS curtain airbag on each side of
the cabin is stored in the roof side
(between the front pillar and a point over
the rear seat). An “SRS AIRBAG” mark is
located at the top of each center pillar.
In a moderate to severe side impact colli-
sion, the SRS curtain airbag on the
impacted side of the vehicle deploys
between the occupant and the side
window and supplements the seatbelt by
reducing the impact on the occupant’s
head.
In a rollover, SRS curtain airbags on both
sides of the vehicle deploy between the
occupant and the side window and
supplement the seatbelt by reducing the
impact to the occupant’s head.
In an offset frontal collision, SRS curtain
airbags on both sides of the vehicle
deploy between the occupant and the side
window and supplement the seatbelt by
reducing the impact to the occupant’s
head and chest. ▼
Operation
The SRS side airbag and SRS curtain
airbag can function only when the ignition
switch is in the “ON” position.
The following airbags deploy inde-
pendently of each other since each has its
own impact sensor.
 Driver’s SRS side airbag
 Front passenger’s SRS side airbag
 SRS curtain airbag (right-hand side)
 SRS curtain airbag (left-hand side)
Therefore, they may not both deploy in the
same accident. Also, the SRS side airbag
and SRS curtain airbag deploys inde-
pendently of the driver’s and front
passenger’s SRS frontal airbags in the
steering wheel and instrument panel.
For the locations of the sensors and
control modules, refer to "Components"
 P68.
▼ After deployment
After the deployment, the SRS side airbag
immediately starts to deflate. The time
required from detection of an impact to
deflation of an SRS side airbag after
deployment is shorter than the blink of an
eye.
The SRS curtain airbag remains inflated
for a while following deployment then
slowly deflates. The SRS side airbag and SRS curtain

airbag deploy even when no one occupies
the seat on the side on which an impact is
applied.
When the SRS side airbag and SRS
curtain airbag deploy, a sudden, fairly loud
inflation noise will be heard and some
smoke will be released. These occur-
rences are a normal result of the deploy-
ment. This smoke does not indicate a fire
in the vehicle.
▼ Example of the type of accident
The SRS side airbag and SRS curtain
airbag are designed as follows:
CAUTION
Do not touch the SRS side airbag
system components around the
front seat seatback with bare hands
right after deployment. Doing so
can cause burns because the com-
ponents can be very hot as a result
of deployment.After deployment, do not touch any
part of the SRS curtain airbag sys-
tem (from the front pillar to the part
of the roof side over the rear seat).
Doing so can cause burns because
the components can be very hot as
a result of deployment.
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SRS Airbag (Supplemental Restraint System Airbag)
87
Seat, Seatbelt and SRS Airbags1
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▽Examples of the types of acci -
dents in which the SRS side
airbag and SRS curtain airbag
are not designed to deploy in
most cases1) The vehicle is involved in frontal colli- sion with another vehicle (moving or stationary).
2) The vehicle is struck from behind.
3) The vehicle pitches end over end.
In the event of accidents like those illus-
trated, the SRS side airbag and SRS
curtain airbag are not designed to deploy
in most cases.1) First impact
2) Second impact
A) SRS curtain airbag
B) SRS side airbagIn an accident where the vehicle is struck
from the side more than once, the SRS
side airbag and SRS curtain airbag deploy
only once on the first impact.
Example: In the case of a double side
impact collision, first with one vehicle and
immediately followed by another from the same direction, once the SRS side airbag

and SRS curtain airbag are activated on
the first impact, they will not be activated
on the second.
■ SRS Airbag System MonitorsSRS airbag system warning lightA diagnostic system continually monitors
the readiness of the SRS airbag system
(including seatbelt pretensioners) with the
ignition switch in the “ON” position. The
SRS airbag system warn ing light will show
normal system operation by illuminating
for approximately 6 seconds when the
ignition switch is turned to the “ON” posi-
tion.
The following components are monitored
by the indicator:
 Front impact sensor
1
3 2
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B
A
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2
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