sensor CHRYSLER CARAVAN 2005 Service Manual

This sensor is integral to the passenger side front
seat belt lower anchor which is secured to the lower
B-pillar, on the passenger side (Fig. 6). The belt ten-
sion sensor consists of a molded plastic housing, a
metal seat belt anchor loop, and a short pigtail wire.
The electronic circuitry of the belt tension sensor is
concealed and protected within the molded plastic
housing.
The belt tension sensor cannot be repaired and, if
faulty or damaged, the entire passenger side front
seat belt and retractor unit must be replaced (Refer
to 8 - ELECTRICAL/RESTRAINTS/SEAT BELT
OUTBOARD FRONT - REMOVAL).
OPERATION
The belt tension sensor is designed to sense the
relative cinch load applied to the passenger side front
seat belt, which provides a logic input to the micro-
processor of the Occupant Classification Module
(OCM). When a load is applied to the seat belt, the
changes in the load are measured by the belt tension
sensor through the seat belt lower anchor. As the
load changes, the circuitry of the belt tension sensor
changes the output voltage of the sensor.
The belt tension sensor receives a nominal five
volts and a ground from the OCM. The OCM then
monitors the belt tension sensor output voltage.
WARNING: Do not connect the battery before per-
forming the OCS Verification Test using the scantool and the appropriate diagnostic information.
Personal injury or death may occur.
For further diagnosis and testing of the belt ten-
sion sensor, the OCM, and related occupant classifi-
cation system components, use a scan tool and the
appropriate diagnostic information.
CHILD RESTRAINT ANCHOR
DESCRIPTION
TheLower Anchors and Tether for CHildren,
or LATCHchild restraint anchorage system provides
for the installation of suitable child restraints in cer-
tain seating positions without using the seat belt pro-
vided for that seating position. The second seat in
these models are equipped with a fixed-position child
restraint upper tether anchor (Fig. 7) and child
restraint lower anchors (Fig. 8). The third seat is
equipped with only a fixed-position child restraint
upper tether anchor in the middle seating position.
Export vehicles are equipped with fixed-position child
restraint upper tether anchors only.
Fig. 6 BELT TENSION SENSOR LOCATION
1 - A-PILLAR
2 - SEAT BELT ANCHOR/BELT TENSION SENSOR
3 - BELT TENSION SENSOR CONNECTOR
Fig. 7 CHILD RESTRAINT UPPER TETHER/ANCHOR
- 2ND ROW
Fig. 8 CHILD RESTRAINT LOWER ANCHORS
SECOND ROW
RSRESTRAINTS8O-9
BELT TENSION SENSOR (Continued)

INSTALLATION
DEPLOYED AIRBAG
(1) Perform clean up procedure (Refer to 8 - ELEC-
TRICAL/RESTRAINTS - STANDARD PROCEDURE
- SERVICE AFTER AN AIRBAG DEPLOYMENT).
(2) Install a new steering column assembly and
lower steering column coupler (Refer to 19 - STEER-
ING/COLUMN - INSTALLATION).
(3) Install the new clockspring.
(4) Connect the 4-way and 6-way connectors
between the clockspring and the instrument panel
wiring harness.
(5) Install the steering column shrouds and con-
nect traction control wire connector (if equipped)
(Refer to 19 - STEERING/COLUMN/LOWER
SHROUD - INSTALLATION).
(6) Install the steering wheel (Refer to 19 -
STEERING/COLUMN/STEERING WHEEL -
INSTALLATION).
(7) Connect the 4±way harness connector to the
speed control/horn harness to the clockspring.
(8) Connect the 2±way connector to the remote
radio control harness.
(9) Install the driver airbag and the two screws
retaining the airbag. Tighten screws to 10 N´m (90
in. lbs.)
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
UNDEPLOYED AIRBAG
(1) Connect the harness connector on the driver
airbag trim cover (horn, speed controls) to the clock-
spring.
(2) Connect the squib connectors to the driver air-
bag.
(3) Position the driver airbag into the steering
wheel.
(4) Install the two screws retaining the airbag.
Tighten screws to 10 N´m (90 in. lbs.)
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
IMPACT SENSOR
DESCRIPTION
FRONT IMPACT SENSORS
There are two front impact sensors (Fig. 21), one
on the left, and one on the right front sides of the
vehicle. These sensors are mounted remotely from
the impact sensor that is internal to the Occupant
Restraint Controller (ORC). The right and left front
and side impact sensors are identical in construction
and calibration and each front impact sensor is
secured with two screws. The front impact sensors
are secured with two screws to the outboard sides of
the right and left front rail tips.
The impact sensor housing has an integral connec-
tor and two mounting ears, each with a metal sleeve
to provide crush protection. A cavity in the center of
the molded black plastic impact sensor housing con-
tains the electronic circuitry of the sensor which
includes an electronic communication chip and an
electronic impact sensor. Potting material fills the
cavity to seal and protect the internal electronic cir-
cuitry and components. The front impact sensors are
each connected to the vehicle electrical system
through the headlamp to dash wire harness.
The front impact sensors cannot be repaired or
adjusted and, if damaged or faulty, they must be
replaced. If a front impact sensor is faulty, only the
sensor needs to be replaced. If the sensor is damaged
or faulty, or if proper tightening torque of the screws
that secure the sensor to the bracket cannot be
achieved, the sensor and bracket must be replaced.
Refer to the proper body diagnostic information for
diagnosis and testing.
Fig. 21 FRONT IMPACT SENSOR
8O - 18 RESTRAINTSRS
DRIVER AIRBAG (Continued)

SIDE IMPACT SENSORS
Three side impact sensors (Fig. 22) are used on
each side of the vehicle. These sensors are mounted
remotely from the bi-directional safing sensor that is
internal to the Occupant Restraint Controller (ORC).
The side and front impact sensors are identical in
construction and calibration and each impact sensor
is secured with two screws. Each side impact sensor
is secured with two screws. The first row side impact
sensor is located in the B-pillar, just above the front
seat belt retractor (Fig. 23). The second row side
impact sensor is located in the sliding door opening,in the lower door track area (Fig. 23). 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 (Fig. 23).
The impact sensor housing has an integral connec-
tor. A cavity in the center of the molded black plastic
impact sensor housing contains the electronic cir-
cuitry of the sensor which includes an electronic com-
munication chip and an electronic impact sensor.
Potting material fills the cavity to seal and protect
the internal electronic circuitry and components. The
side impact sensors are each connected to the vehicle
electrical system through a connector of the body
harness.
The side impact sensors cannot be repaired or
adjusted. If damaged or faulty, they must be
replaced. Refer to the proper body diagnostic infor-
mation for diagnosis and testing.
REMOVAL
FRONT IMPACT SENSOR
The right and left front impact sensors are
mounted identically on the front rail tips.
(1) Open hood, disconnect and isolate the battery
negative cable.
(2)
WARNING: Wait two minutes for the airbag system
reserve capacitor to discharge before beginning
any airbag system or component service. Failure to
do so may result in accidental airbag deployment,
personal injury or death.
Fig. 23 SIDE IMPACT SENSOR LOCATION
1 - FRONT ROW SIDE IMPACT SENSOR 3 - THIRD ROW SIDE IMPACT SENSOR
2 - SECOND ROW SIDE IMPACT SENSOR
Fig. 22 SIDE IMPACT SENSOR
RSRESTRAINTS8O-19
IMPACT SENSOR (Continued)

(3) Hoist vehicle.
(4) Disconnect electrical connector (Fig. 24).
(5) Remove the two screws attaching front impact
sensor to outer rails (Fig. 24).
(6) Remove sensor from vehicle.
SIDE IMPACT SENSORS
B-PILLAR MOUNTED
The right and left front row side impact sensors,
are mounted identically, on opposite sides of the vehi-
cle, in the b-pillar.
(1) Open hood, disconnect and isolate the battery
negative cable.
(2)
WARNING: Wait two minutes for the system reserve
capacitor to discharge before beginning any airbag
component service. Personal injury or death may
result.
(3) Remove the B-pillar lower trim for the side of
the vehicle that you are replacing the side impact
sensor (Refer to 23 - BODY/INTERIOR/B-PILLAR
LOWER TRIM - REMOVAL).
(4) Disconnect the electrical connector from the
impact sensor (Fig. 25).
(5) Remove the four retaining screws to the impact
sensor bracket (Fig. 25).
(6) Remove impact sensor from vehicle (Fig. 26).
SLIDING DOOR OPENING MOUNTED
The right and left second row side impact sensors,
are mounted identically, on opposite sides of the vehi-cle, in the sliding door opening lower rear where the
lower roller arm mounts in the lower door track.
(1) Open hood, disconnect and isolate the battery
negative cable.
(2)
Fig. 24 FRONT IMPACT SENSOR REMOVE/INSTALL
1 - FRONT IMPACT SENSOR WIRE HARNESS RETAINER
2 - FRONT IMPACT SENSOR RETAINING SCREW
3 - FRONT IMPACT SENSOR WIRE HARNESS
4 - FRONT IMPACT SENSOR
5 - LOWER RADIATOR SUPPORT
Fig. 25 FRONT ROW SIDE IMPACT SENSOR AND
BRACKET
1 - B-PILLAR
2 - FRONT ROW SIDE IMPACT SENSOR ELECTRICAL
CONNECTOR
3 - FRONT ROW SIDE IMPACT SENSOR AND MOUNTING
BRACKET
4 - FRONT ROW SIDE IMPACT SENSOR RETAINING SCREW
Fig. 26 FRONT ROW SIDE IMPACT SENSOR/
BRACKET
1 - FRONT ROW SIDE IMPACT SENSOR
2 - SENSOR TO BRACKET ATTACHMENT
3 - FRONT ROW SIDE IMPACT SENSOR MOUNTING BRACKET
8O - 20 RESTRAINTSRS
IMPACT SENSOR (Continued)

WARNING: Wait two minutes for the system reserve
capacitor to discharge before beginning any airbag
component service. Personal injury or death may
result.
(3) Open sliding door to the fullest open position.
(4) Remove the two retaining screws to the impact
sensor (Fig. 27).
(5) Disconnect the electrical connector from the
impact sensor and remove from vehicle (Fig. 27).
QUARTER PANEL MOUNTED
(1) Open hood, disconnect and isolate the battery
negative cable.
(2)
WARNING: Wait two minutes for the system reserve
capacitor to discharge before beginning any airbag
component service. Personal injury or death may
result.
(3) Remove the quarter trim panel for the side of
the vehicle that you are replacing the side impact
sensor (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - REMOVAL).
(4) Remove the two retaining screws to the impact
sensor (Fig. 28).
(5) Disconnect the electrical connector from the
impact sensor and remove from vehicle (Fig. 28).
INSTALLATION
FRONT IMPACT SENSOR
(1) Position sensor in vehicle (Fig. 24).
(2) Install the two retaining screws to the impact
sensor (Fig. 24). Torque screws to 7 N´m (62 in. lbs.).
(3) Connect electrical connector (Fig. 24).
(4) Lower vehicle from hoist.
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
(5) Verify vehicle and system operation.
(6) Close hood.
SIDE IMPACT SENSORS
B-PILLAR MOUNTED
(1) Position sensor bracket in vehicle (Fig. 25).
(2) Install the four retaining screws to the impact
sensor bracket (Fig. 25). Torque screws to 7 N´m (62
in. lbs.).
(3) Connect the electrical connector (Fig. 25).
(4) Install the B-pillar lower trim for the side of
the vehicle that you are replacing the side impact
sensor (Refer to 23 - BODY/INTERIOR/B-PILLAR
LOWER TRIM - INSTALLATION).
Fig. 27 2ND ROW SIDE IMPACT SENSOR
1 - 2ND ROW SIDE IMPACT SENSOR ELECTRICAL CONNECTOR
2 - 2ND ROW SIDE IMPACT SENSOR RETAINING SCREWS
3 - SLIDING DOOR LOWER ROLLER ARM
Fig. 28 3RD ROW SIDE IMPACT SENSOR
1 - 3RD ROW SIDE IMPACT SENSOR
2 - 3RD ROW SIDE IMPACT SENSOR MOUNTING SCREWS
3 - REAR SPEAKER
4 - REAR WHEEL WELL
RSRESTRAINTS8O-21
IMPACT SENSOR (Continued)

WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
(5) Verify vehicle and system operation.
(6) Close hood.
SLIDING DOOR OPENING MOUNTED
(1) Connect electrical connector (Fig. 27).
(2) Position sensor in vehicle (Fig. 27).
(3) Install the two retaining screws to the impact
sensor (Fig. 27). Torque screws to 7 N´m (62 in. lbs.).
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
(4) Verify vehicle and system operation.
(5) Close hood.
QUARTER PANEL MOUNTED
(1) Position sensor in vehicle (Fig. 28).
(2) Connect electrical connector (Fig. 28).
(3) Install the two retaining screws to the impact
sensor (Fig. 28). Torque screws to 7 N´m (62 in. lbs.).
(4) Install the quarter trim panel for the side of
the vehicle that you are replacing the side impact
sensor (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - INSTALLATION).
WARNING: Do not connect the battery negative
cable (Refer to 8 - ELECTRICAL/RESTRAINTS -
DIAGNOSIS AND TESTING - AIRBAG SYSTEM). Per-
sonal injury or death may result if the system test
is not performed first.
(5) Verify vehicle and system operation.
(6) Close hood.
KNEE BLOCKER AIRBAG
DESCRIPTION
The Knee Blocker Airbag (Fig. 29) is located on the
driver side of the vehicle beneath the instrument
panel under steering column cover (Fig. 30).
The knee blocker airbag includes one reaction plate
and one load plate, within which the cushion and
inflator are mounted and sealed. Following a knee
blocker airbag deployment, the knee blocker airbag
and instrument panel assembly must be replaced.
Refer to the proper diagnostic information for diagno-
sis and testing.
OPERATION
The knee blocker airbag is equipped with a single
inflator. When the Occupant Restraint Controller
(ORC) sends the proper electrical signals to the initi-
ator, the electrical energy generates enough heat to
initiate a small pyrotechnic charge which, in turn
ignites chemical pellets within the inflator. Once
ignited, these chemical pellets burn rapidly and pro-
duce a large quantity of inert gas. The inflator is
sealed to the back of the airbag housing and a dif-
fuser in the inflator directs all of the inert gas into
the airbag cushion, causing the cushion to inflate. As
the cushion inflates, the knee blocker airbag trim
deploy. Following an airbag deployment, the airbag
cushion quickly deflates by venting the inert gas
towards the instrument panel through vent holes
within the fabric used to construct the back panel of
the airbag cushion.
Some of the chemicals used to create the inert gas
may be considered hazardous while in their solid
state before they are burned, but they are securely
sealed within the airbag inflator. Typically, the poten-
tially hazardous chemicals are burned during an air-
bag deployment event.
WARNING: The inert gas that is produced when the
chemicals are burned is harmless. However, a small
amount of residue from the burned chemicals may
cause some temporary discomfort if it contacts the
skin, eyes, or breathing passages. If skin or eye irri-
tation is noted, rinse the affected area with plenty
of cool, clean water. If breathing passages are irri-
tated, move to another area where there is plenty of
clean, fresh air to breath. If the irritation is not alle-
viated by these actions, contact a physician.
Fig. 29 KNEE BLOCKER AIRBAG
8O - 22 RESTRAINTSRS
IMPACT SENSOR (Continued)

OCCUPANT CLASSIFICATION
MODULE
DESCRIPTION
The Occupant Classification Module (OCM) (Fig.
34) is secured with two screws to a stamped steel
mounting bracket welded onto the underside of the
passenger front seat cushion frame near the inboard
front corner (Fig. 35). Concealed within a hollow in
the center of the molded plastic OCM housing is a
microprocessor and the other electronic circuitry of
the module. The module housing is sealed to enclose
and protect the internal electronic circuitry. The
OCM software is flash programmable.
A non-calibrated OCM is the only component of the
Occupant Classification System (OCS) that is avail-
able for separate service replacement. The OCS com-
ponents of the passenger side front seat cushion
including the cushion frame, insulator pad, seat
weight bladder and pressure sensor, seat cushion
foam, wiring harness and the OCM are a factory-cal-
ibrated and assembled unit. Once this unit is con-
nected to a vehicle electrically, the calibration
settings are uploaded from the calibrated OCM and
stored in the memory of the Occupant Restraint Con-
troller (ORC). If only the OCM is subsequently
replaced, the new, non-calibrated OCM learns the
proper calibration settings from the ORC after it is
connected to the vehicle electrically.The OCM cannot be adjusted or repaired and, if
damaged or faulty, it must be replaced. The compo-
nents of the passenger front seat cushion are ser-
viced only as a factory-calibrated, assembled and
tamper-evident unit. Only the OCM and the seat
cushion trim are available for separate service
replacement. Once a service replacement package has
been installed in a vehicle, the OCM can thereafter
be serviced only by replacing the entire passenger
front seat cushion with another complete service
replacement package.
OPERATION
The microprocessor in the Occupant Classification
Module (OCM) contains the Occupant Classification
System (OCS) logic circuits. The OCM uses On-Board
Diagnostics (OBD) and can communicate with other
electronic modules in the vehicle as well as with a
scan tool using the Programmable Communications
Interface (PCI) data bus network. This method of
communication is also used for OCS diagnosis and
testing through the 16-way Data Link Connector
(DLC), located on the driver side lower edge of the
instrument panel.
The OCM provides a nominal five volts to both the
pressure sensor of the seat weight bladder beneath
the passenger front seat cushion and to the belt ten-
sion sensor on the passenger front seat belt lower
Fig. 34 OCCUPANT CLASSIFICATION MODULE
(OCM) - TYPICAL
1 - OCCUPANT CLASSIFICATION MODULE
2 - CONNECTOR LOCK TOWER
3 - CONNECTOR RECEPTACLE
4 - MOUNTING TAB (2)
Fig. 35 OCM LOCATION
1 - OCCUPANT CLASSIFICATION MODULE (OCM)
2 - LOCK TOWER
3 - LOCK PIN
4 - CONNECTOR
5 - SCREW (2)
6 - BRACKET
RSRESTRAINTS8O-25

anchor. The OCM then monitors the return voltage
from each of the sensors. The bladder pressure sen-
sor input allows the OCM to determine whether the
passenger front seat is occupied and the relative size
of the occupant by providing a weight-sensing refer-
ence to the load on the seat cushion. The belt tension
sensor provides an additional logic input to the OCM
microprocessor that allows it to distinguish between
the lower seat belt cinch loads of a belted occupant
and the higher loads associated with a belted child
seat.
Pre-programmed decision algorithms and OCS cal-
ibration allow the OCM microprocessor to determine
when the seat cushion load as signaled by the blad-
der pressure sensor and the seat belt cinch load as
signaled by the belt tension sensor indicate that pas-
senger airbag protection is appropriate. When the
programmed conditions are met, the OCM sends the
proper electronic occupant classification messages
over the PCI data bus to the Occupant Restraint
Controller (ORC), and the ORC enables or disables
the deployment circuits for the passenger front sup-
plemental restraints. The ORC also provides a con-
trol output for the Passenger Airbag Disabled (PAD)
indicator in the instrument panel center stack, based
upon the electronic occupant classification messages
it receives from the OCM.
The OCM microprocessor continuously monitors all
of the OCS electrical circuits and components to
determine the system readiness. If the OCM detects
a monitored system fault, it sets an active and stored
Diagnostic Trouble Code (DTC) and sends the appro-
priate electronic messages to the ORC over the PCI
data bus. Then the ORC sets a DTC and sends mes-
sages to control the airbag indicator operation
accordingly. An active fault only remains for the
duration of the fault, or in some cases for the dura-
tion of the current ignition switch cycle, while a
stored fault causes a DTC to be stored in memory by
the OCM and the ORC. For some DTC's, if a fault
does not recur for a number of ignition cycles, the
OCM will automatically erase the stored DTC. For
other internal faults, the stored DTC is latched for-
ever.
The OCM receives battery current from an IPM
high side driver (Run/Start). The OCM receives
ground through a ground circuit of the body wire
harness, which it shares with the ORC. These con-
nections allow the OCM to be operational whenever
the ignition switch is in the Start or ON positions.
To diagnose and test the OCS, use a scan tool and
the appropriate diagnostic information.
REMOVAL
Once any of the original factory-installed compo-
nents except the Occupant Classification Module(OCM) have been replaced with the service replace-
ment package components, the OCM can only be ser-
viced by replacing the entire passenger front seat
cushion unit with another complete service replace-
ment package (Refer to 23 - BODY/SEATS/SEAT
CUSHION - FRONT - REMOVAL).
WARNING: Never replace both the Occupant
Restraint Controller (ORC) and the Occupant Clas-
sification Module (OCM) at the same time. If both
require replacement, replace one, then perform the
Airbag System test (Refer to 8 - ELECTRICAL/RE-
STRAINTS - DIAGNOSIS AND TESTING - AIRBAG
SYSTEM) before replacing the other. Both the ORC
and the OCM store Occupant Classification System
(OCS) calibration data, which they transfer to one
another when one of them is replaced. If both are
replaced at the same time, an irreversible fault will
be set in both modules and the OCS may malfunc-
tion and result in personal injury or death.
(1) Disconnect and isolate the battery negative
cable.
(2)
WARNING: Wait two minutes for the airbag system
reserve capacitor to discharge before beginning
any airbag system or component service. Failure to
do so may result in accidental airbag deployment,
personal injury or death.
(3) Reach under the front edge of the passenger
side front seat cushion to access and remove the lock
pin from the connector lock tower on the Occupant
Classification Module (OCM) (Fig. 36).
(4) Disconnect the passenger front seat wire har-
ness connector for the OCM.
(5) Remove the two screws that secure the OCM to
the OCM bracket.
(6) Remove the OCM from under the passenger
front seat.
INSTALLATION
WARNING: To avoid personal injury or death on
vehicles equipped with the Occupant Classification
System (OCS), only the Occupant Classification
Module (OCM) and the seat cushion trim may be
serviced separately. All other components of the
passenger front seat cushion must be serviced only
as a complete factory-calibrated, assembled and
tamper-evident service replacement package.
Once any of the original factory-installed compo-
nents except the OCM have been replaced with the
service replacement package components, the OCM
can only be serviced by replacing the entire passen-
8O - 26 RESTRAINTSRS
OCCUPANT CLASSIFICATION MODULE (Continued)

The ORC is secured with screws to a stamped steel
mounting bracket welded onto the top of the floor
panel transmission tunnel just behind and under-
neath the instrument panel center stack in the pas-
senger compartment of the vehicle (Fig. 38).
Concealed within a hollow in the center of the die
cast aluminum ORC housing is the electronic cir-
cuitry of the ORC which includes a microprocessor,
an electronic impact sensor, an electronic safing sen-
sor, and an energy storage capacitor. A stamped
metal cover plate is secured to the bottom of the
ORC housing with four screws to enclose and protect
the internal electronic circuitry and components.
An arrow printed on the label on the top of the
ORC housing provides a visual verification of the
proper orientation of the unit, and should always be
pointed toward the front of the vehicle. The ORC
housing has integral mounting flanges. the ORC has
two molded plastic electrical connectors that exits the
right facing side of the ORC housing. These terminal
pins connect the ORC to the vehicle electrical system.
The impact sensor and safing sensor internal to
the ORC are calibrated for the specific vehicle, and
are only serviced as a unit with the ORC. In addi-
tion, there are unique versions of the ORC for vehi-
cles with or without curtain airbags. The ORC cannot
be repaired or adjusted and, if damaged or faulty, it
must be replaced.
OPERATION
The microprocessor in the Occupant Restraint Con-
troller (ORC) contains the supplemental restraint
system logic circuits and controls all of the supple-
mental restraint system components. The ORC uses
On-Board Diagnostics (OBD) and can communicatewith other electronic modules in the vehicle as well
as with the diagnostic scan tool using the Program-
mable Communication Interface (PCI) data bus. This
method of communication is used for control of the
airbag indicator in the ElectroMechanical Instrument
Cluster (EMIC) and for supplemental restraint sys-
tem diagnosis and testing through the 16-way Data
Link Connector (DLC) located on the driver side
lower edge of the instrument panel.
The ORC microprocessor continuously monitors all
of the supplemental restraint system electrical cir-
cuits to determine the system readiness. If the ORC
detects a monitored system fault, it sets an active
and stored Diagnostic Trouble Code (DTC) and sends
electronic messages to the EMIC over the PCI data
bus to turn on the airbag indicator. An active fault
only remains for the duration of the fault, or in some
cases for the duration of the current ignition switch
cycle, while a stored fault causes a DTC to be stored
in memory by the ORC. For some DTC's, if a fault
does not recur for a number of ignition cycles, the
ORC will automatically erase the stored DTC. For
other internal faults, the stored DTC is latched for-
ever.
On models equipped with the Occupant Classifica-
tion System (OCS), the ORC communicates with the
Occupant Classification Module (OCM) over the PCI
data bus. The ORC will internally disable the pas-
senger airbag and seat belt tensioner deployment cir-
cuits if the OCM detects that the passenger side
front seat is unoccupied or that it is occupied by a
load that is inappropriate for an airbag deployment.
The ORC also provides a control output to the Pas-
senger Airbag Disabled (PAD) indicator through the
passenger airbag indicator driver circuit. The OCM
notifies the ORC when it has detected a monitored
system fault and stored a DTC in its memory for any
faulty OCS component or circuit, then the ORC sets
a DTC and controls the airbag indicator operation
accordingly.
The ORC receives battery current through two cir-
cuits; a fused ignition switch output (RUN) circuit
through a fuse in the Junction Block (JB), and a
fused ignition switch output (RUN/START) circuit
through a second fuse in the JB. The ORC receives
ground through a ground circuit of the instrument
panel wire harness. These connections allow the ORC
to be operational whenever the ignition switch is in
the START or ON positions.
The ORC also contains an energy-storage capacitor.
When the ignition switch is in the START or ON
positions, this capacitor is continually being charged
with enough electrical energy to deploy the front sup-
plemental restraint components for up to one second
following a battery disconnect or failure. The purpose
of the capacitor is to provide backup supplemental
Fig. 38 ORC LOCATION
1 - ORC ELECTRICAL CONNECTORS
2 - ORC
3 - ORC MOUNTING SCREWS
8O - 28 RESTRAINTSRS
OCCUPANT RESTRAINT CONTROLLER (Continued)

restraint system protection in case there is a loss of
battery current supply to the ORC during an impact.
Two sensors are contained within the ORC, an
electronic impact sensor and a safing sensor. The
ORC also monitors inputs from eight remote impact
sensors. Two front impact sensors are located on each
outboard side of the lower radiator support, and
three side impact sensors are located on each side of
the vehicle at the B-pillar, in the lower sliding door
opening in front of the C-pillar, and over the rear
wheel well between the C and D-pillars. The elec-
tronic impact sensors are accelerometers that sense
the rate of vehicle deceleration, which provides veri-
fication of the direction and severity of an impact.
The safing sensor is an electronic accelerometer
sensor within the ORC that provides an additional
logic input to the ORC microprocessor. The safing
sensor is used to verify the need for a supplemental
restraint deployment by detecting impact energy of a
lesser magnitude than that of the primary electronic
impact sensors, and must exceed a safing threshold
in order for the airbags to deploy. Vehicles equipped
with curtain airbags, there is a second safing sensor
within the ORC to provide confirmation to the ORC
microprocessor of side impact forces. This second saf-
ing sensor is a bi-directional unit that detects impact
forces from either side of the vehicle.
Pre-programmed decision algorithms in the ORC
microprocessor determine when the deceleration rate
as signaled by the impact sensors and the safing sen-
sors indicate an impact that is severe enough to
require supplemental restraint system protection
and, based upon the severity of the monitored
impact, determines the level of front airbag deploy-
ment force required for each front seating position.
When the programmed conditions are met, the ORC
sends the proper electrical signals to deploy the dual
multistage front airbags at the programmed force
levels, the front seat belt tensioners and, if the vehi-
cle is so equipped, either curtain airbag. For vehicles
equipped with the OCS, the passenger front airbag
and seat belt tensioner will be deployed by the ORC
only if enabled by the OCM messages (PAD indicator
OFF) at the time of the impact.
To diagnose and test the ORC and all airbag sys-
tem components, use a scan tool and the appropriate
diagnostic information.
REMOVAL
WARNING: Never replace both the Occupant
Restraint Controller (ORC) and the Occupant Clas-
sification Module (OCM) at the same time. If both
require replacement, replace one, then perform the
Airbag System test (Refer to 8 - ELECTRICAL/RE-
STRAINTS - DIAGNOSIS AND TESTING - AIRBAGSYSTEM) before replacing the other. Both the ORC
and the OCM store Occupant Classification System
(OCS) calibration data, which they transfer to one
another when one of them is replaced. If both are
replaced at the same time, an irreversible fault will
be set in both modules and the OCS may malfunc-
tion and result in personal injury or death.
(1) Disconnect and isolate the battery negative
cable.
(2)
WARNING: Wait two minutes for the airbag system
reserve capacitor to discharge before beginning
any airbag system or component service. Failure to
do so may result in accidental airbag deployment,
personal injury or death.
(3) Remove storage bin from instrument panel
(Refer to 23 - BODY/INSTRUMENT PANEL/STOR-
AGE BIN - REMOVAL).
(4) Remove three bolts holding ORC to floor
bracket (Fig. 39).
(5) Disconnect the wire connectors from the ORC
(Fig. 39).
(6) Remove the ORC from vehicle.
INSTALLATION
WARNING: Do not install ORC if mounting location
is deformed or damaged. This will cause the ORC
to be improperly located and could result in occu-
pant personal injury or death.
WARNING: Use correct screws when installing the
ORC.
Fig. 39 ORC - REMOVE/INSTALL
1 - ORC ELECTRICAL CONNECTORS
2 - ORC
3 - ORC MOUNTING SCREWS
RSRESTRAINTS8O-29
OCCUPANT RESTRAINT CONTROLLER (Continued)