the ORC for control of the airbag indicator in the EMIC. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/COMMUNICATION - DESCRIPTION).
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 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 supplemental restraint system because they were designed and are
intended to enhance the protection for the occupants of the vehicle only when used in conjunction 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 maxi-
mum safety benefit from the factory-installed supplemental restraint system.
The supplemental restraint system electrical circuits are continuously monitored and controlled by a microprocessor
and software contained within the Occupant Restraint Controller (ORC). An airbag indicator 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 system. 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 system electrical circuits. Such a problem
may cause airbags 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 sig-
nals the inflator of the appropriate airbags to deploy their 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 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 distribute the crash energy from the driver and the front seat passenger to the structure
of the instrument panel. The seat belt tensioners remove the slack from the front seat belts to provide further assur-
ance that the driver and front seat passenger are properly positioned and restrained for an airbag deployment.
The airbag deployment and deflation occur very 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 about 40 milliseconds. Within one to two
seconds from the moment of impact, the airbags are almost entirely deflated. The times cited for these events are
approximations, 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 ORC monitors a problem in any of the dual front airbag system circuits or components, including the seat
belt tensioners, it stores a fault code or Diagnostic Trouble Code (DTC) in its memory circuit and sends an elec-
tronic message to the EMIC to turn on the airbag indicator. Proper testing of the supplemental restraint system
components, the Controller Area Network (CAN) data bus, the electronic message inputs to and outputs from the
EMIC or the ORC, as well as the retrieval or erasure of a DTC from the ORC or the EMIC requires the use of a
diagnostic scan tool and the appropriate diagnostic information.
See the owner’s manual in the vehicle glove box for more information on the features, use and operation of all of
the passive restraints.
OCCUPANT CLASSIFICATION SYSTEM
In vehicles equipped with the Occupant Classification System (OCS), the OCS automatically suppresses or enables
passenger airbag and seat belt tensioner operation based upon whether or not the passenger front seat is occupied
and, if the seat is occupied, classifies the size of the occupant and whether the seat is occupied by a child seat.
The OCS has an Occupant Classification Module (OCM) that monitors inputs from the seat weight sensors under
the passenger side front seat cushion and from the seat track position sensors on the passenger side and driver
8O - 366
RESTRAINTS - SERVICE INFORMATION
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