2004 SUBARU IMPREZA sensor

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Seat, seatbelt and SRS airbags
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!Seatbelt maintenance
To clean the seatbelts, use a mild soap and lukewarm
water. Never bleach or dye the belts because this
could seriously affect their strength.
Inspect the seatbelts and attachments including the
webbing and all hardware periodically for cracks, cuts,
gashes, tears, damage, loose bolts or worn areas. Re-
place the seatbelts even if only minor damage is
found.
" Keep the belts free of polishes, oils, chemi-
cals and particularly battery acid. " Never attempt to make modifications or
changes that will prevent the seatbelt from op-
erating properly.
Front seatbelt pretensioners
The driver’s and front passenger’s seatbelts have a
seatbelt pretensioner. The seatbelt pretensioners are
designed to be activated in the event of an accident in-
volving a moderate to severe frontal collision.
The pretensioner sensor also serves as the frontal
SRS airbag sensor. If the sensor detects a certain pre-
determined amount of force during a frontal collision,
the front seatbelt is quickly drawn back in by the re-
tractor to take up the slack so that the belt more effec-
tively restrains the front seat occupant.
When a seatbelt pretensioner is activated, an operat-
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Seat, seatbelt and SRS airbags
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your SUBARU dealer.
! System monitors
A diagnostic system continually monitors the readi-
ness of the seatbelt pretensioner while the vehicle is
being driven. The seatbelt pretensioners share the
control module with the SRS airbag system. There-
fore, if any malfunction occurs in a seatbelt preten-
sioner, the SRS airbag system warning light will illumi-
nate. The SRS airbag system warning light will show
normal system operation by lighting for about 6 sec-
onds when the ignition key is turned to the “ON” posi- tion.
The following components are monitored by the indi- cator:"
Front sub sensor (Right hand side)
" Front sub sensor (Left hand side)
" Airbag control module (including impact sensors)
" Seatbelt pretensioner (driver’s side)
" Seatbelt pretensioner (Passenger’s side)
" All related wiring
" And all other airbag components
In the event of a malfunction indicated by any of follow-
ing, the vehicle should be taken promptly to your near-
est SUBARU dealer to have the system checked. Un-
less checked and repaired, the seatbelt pretensioners
and SRS airbag will not function reliably: " Flashing or flickering of the indicator light.
" No illumination of the warning light when the ignition
switch is first turned to the “ON” position." Continuous illumination of the warning light.
" Illumination of the warning light while driving.
! System servicing
"When discarding a seatbelt retractor assem-
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Seat, seatbelt and SRS airbags
bly or scrapping the entire car damaged by a
collision, consult your SUBARU dealer. "
Tampering with or disconnecting the sys-
tem’s wiring could result in accidental activa-
tion of the seatbelt pretensioner and/or SRS air-
bag or could make the system inoperative,
which may result in serious injury. The wiring
harnesses of the seatbelt pretensioner and SRS
airbag systems are covered with yellow insula-
tion and the connectors of the system are yel-
low for easy identification. Do not use electrical
test equipment on any circuit related to the
seatbelt pretensioner and SRS airbag systems.
For required servicing of the seatbelt preten-
sioner, see your nearest SUBARU dealer.
The front sub sensors are located in both front
fenders and the SRS airbag control module in-
cluding the impact sensors is located under the
center console. If you need service or repair in
those areas or near the front seatbelt retrac-
tors, we recommend that you have an autho-
rized SUBARU dealer perform the work.
NOTE
If the front part of the vehicle is damaged in an ac-
cident to the extent that the seatbelt pretensioner
does not operate, contact your SUBARU dealer as
soon as possible. ! Precautions against vehicle modifica- tion
Always consult your SUBARU dealer if you want to in-
stall any accessory parts to your vehicle.
Do not perform any of the following modifica-
tions. Such modifications can interfere with
proper operation of the seatbelt pretensioners. " Attachment of any equipment (bush bar,
winches, snow plow, skid plate, etc.) other than
SUBARU genuine accessory parts to the front
end." Modification of the suspension system or
front end structure." Installation of a tire of different size and con-
struction from the tires specified on the tire
placard attached to the driver’s door jamb.

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Seat, seatbelt and SRS airbags
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UG1034BB
1) Airbag control module (including
impact sensors)
2) Airbag module (driver’s side)
3) Airbag module (passenger’s side)
4) Front sub sensor (left hand side)
5) Front sub sensor (right hand side)
6) Side airbag module (driver’s
side — if equipped)
7) Side airbag module (passen-
ger’s side — if equipped)
8) Side airbag sensor (driver’s side — if equipped)
9) Side airbag sensor (passenger’s side — if equipped)
10) Airbag wiring (yellow)
11) Seatbelt pretensioner (driver’s side)
12) Seatbelt pretensioner (passen-
ger’s side)

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Seat, seatbelt and SRS airbags
The SRS airbag can function only when the ignition
switch is in the “ON” position.
If the front sub sensors inside the both front fenders
and the impact sensors in the airbag control module
detect a certain predetermined amount of force during
a frontal collision, the control module sends signals to
the frontal airbag modules instructing them to inflate
the SRS frontal airbags. Then both airbag modules
produce gas, which instantly inflates driver’s and pas-
senger’s SRS frontal airbags. After the deployment,
the SRS airbags immediately start to deflate so that
the driver’s vision is not obstructed. The time required
from detecting impact to the deflation of the SRS air-
bag after deployment is shorter than the blink of an eye.
The front passenger’s SRS frontal airbag deploys to-
gether with driver’s SRS frontal airbag even when no
one occupies the front passenger’s seat.
Although it is highly unlikely that the SRS airbag would
activate in a non-accident situation, should it occur,
the SRS airbag will deflate quickly, not obscuring vi-
sion and will not interfere with the driver’s ability to
maintain control of the vehicle.
When the SRS airbag deploys, a sudden, fairly loud
inflation noise will be heard and some smoke will be
released. These occurrences are normal result of the
deployment. This smoke does not indicate a fire in the vehicle.
Do not touch the SRS airbag system compo-
nents around the steering wheel and dash-
board with bare hands right after deployment.
Doing so can cause burns because the compo-
nents can be very hot as a result of deployment.
The SRS frontal airbag is designed to deploy in the
event of an accident involving a moderate to severe
frontal collision. It is basically not designed to deploy
in lesser frontal impacts because the necessary pro-
tection can be achieved by the seatbelt alone. Also, it
is basically not designed to deploy in side or rear im-
pacts or in roll-over accidents because deployment of
the SRS frontal airbag would not help the occupant in
those situations. The SRS airbag is designed to func-
tion on a one-time-only basis.
SRS airbag deployment depends on the level of force
experienced in the passenger compartment during a
collision. That level differs from one type of collision to
another, and it may have no bearing on the visible

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Seat, seatbelt and SRS airbags
C) After deployment, SRS side airbag starts to deflate im-
mediately.
The SRS side airbag can function only when the igni-
tion switch is in the “ON” position.
The driver’s and front passenger’s SRS side airbags
deploy independently of each other since each has its
own impact sensor. Also, the SRS side airbag deploys
independently of the frontal airbags in the steering
wheel and instrument panel.
An impact sensor is incorporated into each of the ve-
hicle’s center pillars. If either sensor detects a certain
predetermined amount of force during a side impact
collision, the control module sends a signal to the side
airbag module on the impacted side of the vehicle, in-
structing it to inflate the SRS side airbag. Then the
side airbag module produces gas, which instantly in-
flates the SRS side airbag. After the deployment, the
SRS side airbag immediately starts to deflate. The
time required from detecting impact to the deflation of
the SRS side airbag after deployment is shorter than
the blink of an eye.
The SRS side airbag deploys even when no one occu-
pies the seat on the side on which an impact is ap-
plied. When the SRS side airbag deploys, a sudden, fairly
loud inflation noise will be heard and some smoke will
be released. These occurrences are normal result of
the deployment. This smoke does not indicate a fire in
the vehicle.
Do not touch the SRS side airbag system com-
ponents around the front seatback with bare
hands right after deployment. Doing so can
cause burns because the components can be
very hot as a result of deployment.
The SRS side airbag is designed to deploy in the event
of an accident involving a moderate to severe side im-
pact collision. It is basically not designed to deploy in
lesser side impact. Also, it is basically not designed to
deploy in frontal or rear impacts because SRS side air-
bag deployment would not help the occupant in those
situations.
Each SRS side airbag is designed to function on a one-time-only basis.
SRS side airbag deployment depends on the level of
force experienced in the passenger compartment dur-
ing a side impact collision. That level differs from one

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Seat, seatbelt and SRS airbags
The SRS side airbag is basically not designed to de-
ploy if the vehicle is involved in a frontal collision or is
struck from behind. Examples of such accidents are il-
lustrated.
1) First impact
2) Second impact
In an accident where the vehicle is struck from the side
more than once, the SRS side airbag deploys only
once.
Example: In the case of a double side impact collision,
first with one vehicle and immediately followed by an-
other from the same direction, once the SRS side air-
bag is activated on the first impact, it will not be acti- vated on the second. !
SRS airbag system monitors
A diagnostic system continually monitors the readi-
ness of the SRS airbag system while the vehicle is be-
ing driven. The SRS airbag system warning light “AIR-
BAG” will show normal system operation by lighting for
about 6 seconds when the ignition key is turned to the“ON” position.
The following components are monitored by the indi- cator:" Front sub sensor (Right hand side)
" Front sub sensor (Left hand side)
2
1
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Seat, seatbelt and SRS airbags
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"Airbag control module (including impact sensors)
" Frontal airbag module (Driver’s side)
" Frontal airbag module (Passenger’s side)
" Side airbag sensor (Driver’s side — if equipped)
" Side airbag sensor (Passenger’s side — if
equipped) " Side airbag module (Driver’s side — if equipped)
" Side airbag module (Passenger’s side — if
equipped)" Seatbelt pretensioner (Driver’s side)
" Seatbelt pretensioner (Passenger’s side)
" All related wiring
In the event of a malfunction indicated by any of follow-
ing, the vehicle should be taken promptly to your near-
est SUBARU dealer to have the system checked. Un-
less checked and repaired, the SRS airbags will not
function reliably: " Flashing or flickering of the indicator light.
" No illumination of the warning light when the ignition
switch is first turned to the “ON” position." Continuous illumination of the warning light.
" Illumination of the warning light while driving. !
SRS airbag system servicing
"When discarding an airbag module or scrap-
ping the entire car damaged by a collision, con-
sult your SUBARU dealer." The SRS airbag has no user-serviceable
parts. Do not use electrical test equipment on
any circuit related to the SRS airbag system.
For required servicing of the SRS airbag, see
your nearest SUBARU dealer. Tampering with
or disconnecting the system’s wiring could re-
sult in accidental inflation of the SRS airbag or
could make the system inoperative, which may
result in serious injury. The wiring harnesses of
the SRS airbag system are covered with yellow
insulation and system connectors are yellow
for easy identification.
If you need service or repair in areas listed be-
low, we recommend that you have an autho-
rized SUBARU dealer perform the work. The
SRS airbag control module, impact sensors
and airbag modules are stored in these areas.