DaimlerChrysler SPRINTER2006 Service Manual page 90

8O - 4 RESTRAINTS
and to the supplemental restraint system compo-
nents through the use of a combination of soldered
splices, splice block connectors, and many different
types of wire harness terminal connectors and insu-
lators. Refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, further
details on wire harness routing and retention, as well
as pin-out and location views for the various wire
harness connectors, splices and grounds.
OPERATION
ACTIVE RESTRAINTS
The primary passenger restraints in this or any
other vehicle are the standard equipment factory-in-
stalled seat belts. Seat belts are referred to as an
active restraint because the vehicle occupants are
required to physically fasten and properly adjust
these restraints in order to benefit from them. See
the owner's manual in the vehicle glove box for more
information on the features, use and operation of all
of the factory-installed active restraints.
PASSIVE RESTRAINTS
The passive restraints are referred to as a supple-
mental restraint system because they were designed
and are intended to enhance the protection for the
occupants of the vehicle only when used in conjunc-
tion with the seat belts. They are referred to as pas-
sive restraints because the vehicle occupants are not
required to do anything to make them operate; how-
ever, the vehicle occupants must be wearing their
seat belts in order to obtain the maximum safety
benefit from the factory-installed
restraint system.
The supplemental restraint system electrical cir-
cuits are continuously monitored and controlled by a
microprocessor and software contained within the
Airbag Control Module (ACM). An airbag indicator in
the ElectroMechanical Instrument Cluster (EMIC)
illuminates for about four seconds as a bulb test each
time the ignition switch is turned to the On or Start
positions. Following the bulb test, the airbag indica-
tor is turned on or off by the ACM to indicate the
status of the supplemental restraint system. If the
airbag indicator comes on either solid or flashing at
any time other than during the bulb test, it indicates
that there is a problem in the supplemental restraint
system electrical circuits. Such a problem may cause
airbags not to deploy when required, or to deploy
when not required.
Deployment of the
depends upon the angle and severity of an impact.
Deployment is not based upon vehicle speed; rather,
deployment is based upon the rate of deceleration as
measured by the forces of gravity (G force) upon the
impact sensor(s). When an impact is severe enough,
supplemental
supplemental restraints
the microprocessor in the ACM signals the inflator of
the appropriate airbag units to deploy their airbag
cushions. The front seat belt tensioners are provided
with a deployment signal by the ACM in conjunction
with the driver and passenger airbags.
During a frontal vehicle impact, the knee blockers
work in concert with properly fastened and adjusted
seat belts to restrain both the driver and the front
seat passenger in the proper position for an airbag
deployment. The knee blockers also absorb and dis-
tribute the crash energy from the driver and the
front seat passenger to the structure of the instru-
ment panel. The seat belt tensioners remove the
slack from the front seat belts to provide further
assurance that the driver and front seat passenger
are properly positioned and restrained for an airbag
deployment.
Typically, the vehicle occupants recall more about
the events preceding and following a collision than
they do of an airbag deployment itself. This is
because the airbag deployment and deflation occur so
rapidly. In a typical 48 kilometer-per-hour (30 mile-
per-hour) barrier impact, from the moment of impact
until the airbags are fully inflated takes only a few
milliseconds. Within one to two seconds from the
moment of impact, the airbags are almost entirely
deflated. The times cited for these events are approx-
imations, which apply only to a barrier impact at the
given speed. Actual times will vary somewhat,
depending upon the vehicle speed, impact angle,
severity of the impact, and the type of collision.
When the ACM monitors a problem in any of the
airbag system circuits or components, including the
seat belt tensioners, it stores a fault code or Diagnos-
tic Trouble Code (DTC) in its memory circuit and
sends a hard wired output to the EMIC to turn on
the airbag indicator. If the EMIC detects a problem
in the airbag indicator or airbag indicator circuit, the
cluster will flash the seatbelt indicator on and off.
Proper testing of the supplemental restraint system
components as well as the retrieval or erasure of a
DTC from the ACM requires the use of a diagnostic
scan tool. Refer to the appropriate diagnostic infor-
mation.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of all of the factory-installed passive restraints.
VA