Pontiac 2004 Grand Prix - Manual (Page 59)

When Should an Air Bag Inflate?
The driver’s and right front passengers frontal air bags
are designed to deploy only in moderate to severe
frontal, or near-frontal crashes. But they are designed to
inflate only if the impact speed is above the system’s
designed “threshold level.”
In addition, your vehicle has “dual stage” frontal air
bags, which adjust the amount of restraint according to
crash severity. For moderate frontal impacts, these
air bags 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
doesn’t move or deform, the threshold level for the
reduced deployment is about 12 to 16 mph
(19 to 26 km/h), and the threshold level for a full
deployment is about 18 to 24 mph (29 to 38.5 km/h).
The threshold level can vary, however, with specific
vehicle design, so that it can be somewhat above
or below this range.
If your vehicle strikes something that will move or
deform, such as a parked car, the threshold level will be
higher. The driver’s and right front passenger’s frontal
air bags are not designed to inflate in rollovers, rear
impacts, or in many side impacts because inflation
would not help the occupant.
The side impact air bags are designed to inflate in
moderate to severe side crashes. A side impact air bag
will inflate if the crash severity is above the system’s
designed “threshold level”. The threshold level can vary
with specific vehicle design. Side impact air bags are
not designed to inflate in frontal or near-frontal impacts,
rollovers or rear impacts, because inflation would not
help the occupant. A side impact air bag will only deploy
on the side of the vehicle that is struck.
In any particular crash, no one can say whether an air
bag should have inflated simply because of the damage
to a vehicle or because of what the repair costs were.
For frontal air bags, inflation is determined by the angle
of the impact and how quickly the vehicle slows down
in frontal or near-frontal impacts. For side impact
air bags, inflation is determined by the location and
severity of the impact.
What Makes an Air Bag Inflate?
In an impact of sufficient severity, the air bag sensing
system detects that the vehicle is in a crash. For
both frontal and side impact air bags, the sensing
system triggers a release of gas from the inflator, which
inflates the air bag. The inflator, air bag, and related
hardware are all part of the air bag modules inside the
steering wheel and in the instrument panel in front
of the right front passenger and in the ceiling of
the vehicle, near the side windows.
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