GMC 2007 Sierra - Manual (Page 97)

Dual Stage Airbags
If your vehicle has frontal airbags with dual stage
deployment, the amount of restraint will adjust
according to crash severity. Your vehicle has
electronic frontal sensors which help the sensing
system distinguish between a moderate and a
more severe frontal impact. For moderate frontal
impacts, these airbags inflate at a level less
than full deployment. For more severe frontal
impacts, full deployment occurs. If the front of your
vehicle goes straight into a wall that does not
move or deform, the threshold level for the
reduced deployment is about 10 to 16 mph
(16 to 25 km/h), and the threshold level for a full
deployment is about 20 to 30 mph (32 to 48 km/h).
The threshold level can vary, however, with
specific vehicle design, so that it can be somewhat
above or below this range.
Vehicle’s with dual stage airbags also have
special sensors which enable the sensing system
to monitor the position of both the driver and
passenger front seats. The seat position sensor
provides information which is used to determine if
the airbags should deploy at a reduced level or
at full deployment.
What Makes an Airbag Inflate?
In an impact of sufficient severity, the airbag
sensing system detects that the vehicle is in a
crash. The sensing system triggers a release of gas
from the inflator, which inflates the airbag. The
inflator, airbag, and related hardware are all part of
the airbag modules inside the steering wheel and in
the instrument panel in front of the right front
passenger.
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