²Occupant Classification Module- Vehicles
equipped with the Occupant Classification System
(OCS) include an Occupant Classification Module
(OCM) which is secured to a stamped steel mounting
bracket on the underside of the passenger side front
seat cushion frame.
²Occupant Restraint Controller- The Occu-
pant Restraint Controller (ORC) is also sometimes
referred to as the Airbag Control Module (ACM). The
ORC is located on a mount on the floor transmission
tunnel just underneath the instrument panel center
stack (Fig. 3).
²Passenger Airbag- The passenger airbag is
located on the instrument panel, beneath the instru-
ment panel top pad and above the glove box on the
passenger side of the vehicle (Fig. 3).
²Passenger Airbag Disabled (PAD) Indicator
- Vehicles equipped with the Occupant Classification
System (OCS) include a passenger airbag disabled
(PAD) indicator which is located in the instrument
panel center stack (Fig. 3).
²Passenger Knee Blocker- The passenger knee
blocker is a structural reinforcement that is integral
to and concealed within the glove box door (Fig. 3).
²Seat Belt Tensioner- A seat belt tensioner is
integral to both front seat belt buckles. The seat belt
buckles are secured to the inner seat frame sides,
beneath a cushion trim panel.
²Seat Weight Bladder and Pressure Sensor
Assembly- Vehicles equipped with the Occupant
Classification System (OCS) include a seat weight
bladder that is sandwiched between an insulator pad
on the top of the passenger side front seat pan and
the seat cushion foam padding. A short hose connects
the bladder to a pressure sensor which is secured to
the Occupant Classification Module (OCM) mounting
bracket on the underside of the passenger side front
seat cushion frame.
²Side Impact Sensors- Six side impact sensors
are used on vehicles equipped with the curtain air-
bags, three left side and three right side. The first
row side impact sensor is located in the B-pillar, just
above the front seat belt retractor. The second row
side impact sensor is located in the sliding side door
track opening, just in front of the C-pillar. The third
row side impact sensor is located behind the quarter
trim panel, above the rear tire wheel well, between
the C and D-pillars.
The ORC, the OCM, and the cluster each contain a
microprocessor and programming that allow them to
communicate with each other using the Programma-
ble Communications Interface (PCI) data bus net-
work. This method of communication is used by the
ORC for control of the airbag indicators.OPERATION
ACTIVE RESTRAINTS
The primary passenger restraints in this or any
other vehicle are the seat belts and child restraint
anchors. Seat belts and child restraint anchors are
referred to as an active restraint because the vehicle
occupants are required to physically fasten and prop-
erly 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 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 vehicleONLYwhen used in con-
junction with the seat belts. They are referred to as
passive restraints because the vehicle occupants are
not required to do anything to make them operate;
however, the vehicle occupants must be wearing their
seat belts in order to obtain the maximum safety
benefit from the supplemental restraint system.
The supplemental restraint system electrical cir-
cuits are continuously monitored and controlled by a
microprocessor and software contained within the
Occupant Restraint Controller (ORC). An airbag indi-
cator in the ElectroMechanical Instrument Cluster
(EMIC) illuminates for about seven seconds as a bulb
test each time the ignition switch is turned to the
ON or START positions. Following the bulb test, the
airbag indicator is turned ON or OFF by the ORC to
indicate the status of the supplemental restraint sys-
tem. If the airbag indicator comes ON at any time
other than during the bulb test, it indicates that
there is a problem in the supplemental restraint sys-
tem electrical circuits. Such a problem may cause air-
bags not to deploy when required, or to deploy when
not required.
Deployment of the supplemental restraints
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 sensors. When an impact is severe enough,
the microprocessor in the ORC 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 ORC in conjunction
with the front airbags. During a frontal vehicle
impact, the knee blockers work in concert with prop-
erly 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 distribute the crash energy from the
8O - 4 RESTRAINTSRS
RESTRAINTS (Continued)
