Subaru 2002 Impreza Service Manual page 386

CONSTRUCTION
Airbag System
B: AIRBAG CONTROL MODULE
The airbag control module is installed in front of the front floor tunnel. It detects the vehicle's decel-
eration by receiving electrical signals from its inside safety and electric sensors as well as the front
sub sensors and judges whether to inflate the airbags. This control module has a built-in self-diag-
nosis function. If a fault occurs inside the system, it lights up the airbag warning light in the com-
bination meter. The fault data is stored in the module. A back-up power supply is provided for pos-
sible damage to the battery during an accident, and a boosting circuit is built into the module in
case of a battery voltage drop.
NF0228
C: FRONT SUB SENSOR
One front sub sensor is installed on each side, in front of the front wheel apron wall. The front sub
sensor is a pendulum type sensor. If the sensor receives a frontal impact exceeding a certain limit,
the mass in the sensor rotates forward to turn the switch ON.
v
Mass
0
c3
Switch.contacts
NF0229
AB-6