What Makes An Airbag Inflate - GMC 2009 Envoy Denali Owner's Manual

Your vehicle has roof-rail airbags. See Airbag System
on page 1-55. Roof-rail airbags are intended to inflate in
moderate to severe side crashes. In addition, these
roof-rail airbags are intended to inflate during a rollover.
Roof-rail airbags will inflate if the crash severity is
above the system's designed threshold level. The
threshold level can vary with specific vehicle design.
Roof-rail airbags are not intended to inflate in frontal
impacts, near-frontal impacts, or rear impacts. Both
roof-rail airbags will deploy when either side of
the vehicle is struck or if the sensing system predicts
that the vehicle is about to roll over.
In any particular crash, no one can say whether an
airbag should have inflated simply because of the
damage to a vehicle or because of what the repair costs
were. For frontal airbags, inflation is determined by
what the vehicle hits, the angle of the impact, and how
quickly the vehicle slows down. For roof-rail airbags,
deployment is determined by the location and severity of
the side impact. In a rollover event, roof-rail airbag
deployment is determined by the direction of the roll.
What Makes an Airbag Inflate?
In a deployment event, the sensing system sends an
electrical signal triggering a release of gas from
the inflator. Gas from the inflator fills the airbag causing
the bag to break out of the cover and deploy. The
inflator, the airbag, and related hardware are all part of
the airbag module.
Frontal airbag modules are located inside the steering
wheel and instrument panel. For vehicles with
roof-rail airbags, there are airbag modules in the ceiling
of the vehicle, near the side windows that have
occupant seating positions.
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