2002 JEEP LIBERTY turn

is located on the back side of each vertical member of
the radiator support.
²Passenger Airbag- The passenger airbag is
located on the instrument panel, beneath the passen-
ger airbag door on the instrument panel above the
glove box on the passenger side of the vehicle.
²Passenger Knee Blocker- The passenger knee
blocker is a structural reinforcement that is integral
to and concealed within the glove box door.
²Seat Belt Tensioner- The seat belt tensioner
is integral to the driver side front seat belt retractor
unit on vehicles equipped with dual front airbags.
²Side Impact Airbag Control Module-Two
Side Impact Airbag Control Modules (SIACM) are
used on vehicles with the optional side curtain air-
bags, one left side and one right side. One SIACM is
located behind the B-pillar trim near the base of each
B-pillar.
²Side Curtain Airbag- In vehicles equipped
with this option, a side curtain airbag is located on
each inside roof side rail above the headliner, and
extends from the A-pillar to just beyond the C-pillar.
The ACM, both SIACMs, and the EMIC each con-
tain a central processing unit and programming that
allow them to communicate with each other using
the Programmable Communication Interface (PCI)
data bus network. This method of communication is
used by the ACM for control of the airbag indicator
on all models equipped with dual front airbags.
(Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/COMMUNICATION - DESCRIP-
TION).
Hard wired circuitry connects the supplemental
restraint system components to each other through
the electrical system of the vehicle. These hard wired
circuits are integral to several wire harnesses, which
are routed throughout the vehicle and retained by
many different methods. These circuits may be con-
nected to each other, to the vehicle electrical system,
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 stan-
dard equipment factory-installed seat belts. Seat
belts are referred to as an active restraint because
the vehicle occupants are required to physically fas-ten 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 fea-
tures, use and operation of all of the factory-installed
active restraints.
PASSIVE RESTRAINTS The passive restraints
system is referred to as a supplemental restraint sys-
tem because they were designed and are intended to
enhance the protection for the vehicle occupants of
the vehicleonlywhen used in conjunction with the
seat belts. They are referred to as passive systems
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 facto-
ry-installed supplemental restraint systems.
The supplemental restraint system electrical cir-
cuits are continuously monitored and controlled by a
microprocessor and software contained within the
Airbag Control Module (ACM) and, on vehicles
equipped with the side curtain airbags, both Side
Impact Airbag Control Modules (SIACM). An airbag
indicator in the ElectroMechanical Instrument Clus-
ter (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 ACM
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 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 ACM or the SIACM signals
the inflator unit of the airbag module to deploy the
airbag. The seat belt tensioner is provided with a
deployment signal by the ACM in conjunction with
the driver airbag. During a frontal vehicle impact,
the knee blockers work in concert with properly fas-
tened 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 tensioner
removes the slack from the driver side front seat belt
to provide further assurance that the driver is prop-
erly positioned and restrained for an airbag deploy-
ment.
8O - 4 RESTRAINTSKJ
RESTRAINTS (Continued)

Typically, the vehicle occupants recall more about
the events preceding and following a collision than
they have 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 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 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
dual front airbag system circuits or components,
including the seat belt tensioner, it stores a fault
code or Diagnostic Trouble Code (DTC) in its memory
circuit and sends an electronic message to the EMIC
to turn on the airbag indicator. When the SIACM
monitors a problem in any of the side curtain airbag
system circuits or component, it stores a fault code or
Diagnostic Trouble Code (DTC) in its memory circuit
and sends an electronic message to the ACM, and the
ACM sends an electronic message to the EMIC to
turn on the airbag indicator. Proper testing of the
airbag system components, the Programmable Com-
munication Interface (PCI) data bus, the data bus
message inputs to and outputs from the EMIC, the
SIACM, or the ACM, as well as the retrieval or era-
sure of a DTC from the ACM, SIACM, or EMIC
requires the use of a DRBIIItscan tool. Refer to 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 factory-installed passive restraints.
WARNING - RESTRAINT SYSTEM
WARNING: DURING AND FOLLOWING ANY SEAT
BELT SERVICE, CAREFULLY INSPECT ALL SEAT
BELTS, BUCKLES, MOUNTING HARDWARE, AND
RETRACTORS FOR PROPER INSTALLATION,
OPERATION, OR DAMAGE. REPLACE ANY BELT
THAT IS CUT, FRAYED, OR TORN. STRAIGHTEN
ANY BELT THAT IS TWISTED. TIGHTEN ANY
LOOSE FASTENERS. REPLACE ANY BELT THAT
HAS A DAMAGED OR INOPERATIVE BUCKLE OR
RETRACTOR. REPLACE ANY BELT THAT HAS A
BENT OR DAMAGED LATCH PLATE OR ANCHOR
PLATE. NEVER ATTEMPT TO REPAIR A SEAT BELT
COMPONENT. ALWAYS REPLACE DAMAGED OR
FAULTY SEAT BELT COMPONENTS WITH THE COR-
RECT, NEW AND UNUSED REPLACEMENT PARTS
LISTED IN THE DAIMLERCHRYSLER MOPAR PARTS
CATALOG.WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSOR, SIDE CURTAIN AIRBAG,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
WARNING: AN AIRBAG INFLATOR UNIT MAY CON-
TAIN SODIUM AZIDE AND POTASSIUM NITRATE.
THESE MATERIALS ARE POISONOUS AND
EXTREMELY FLAMMABLE. CONTACT WITH ACID,
WATER, OR HEAVY METALS MAY PRODUCE HARM-
FUL AND IRRITATING GASES (SODIUM HYDROXIDE
IS FORMED IN THE PRESENCE OF MOISTURE) OR
COMBUSTIBLE COMPOUNDS. AN AIRBAG INFLA-
TOR UNIT MAY ALSO CONTAIN A GAS CANISTER
PRESSURIZED TO OVER 2500 PSI. DO NOT
ATTEMPT TO DISMANTLE AN AIRBAG UNIT OR
TAMPER WITH ITS INFLATOR. DO NOT PUNCTURE,
INCINERATE, OR BRING INTO CONTACT WITH
ELECTRICITY. DO NOT STORE AT TEMPERATURES
EXCEEDING 93É C (200É F).
WARNING: WHEN HANDLING A SEAT BELT TEN-
SIONER RETRACTOR, PROPER CARE SHOULD BE
EXERCISED TO KEEP FINGERS OUT FROM UNDER
THE RETRACTOR COVER AND AWAY FROM THE
SEAT BELT WEBBING WHERE IT EXITS FROM THE
RETRACTOR COVER.
WARNING: REPLACE ALL RESTRAINT SYSTEM
COMPONENTS ONLY WITH PARTS SPECIFIED IN
THE DAIMLERCHRYSLER MOPAR PARTS CATA-
LOG. SUBSTITUTE PARTS MAY APPEAR INTER-
CHANGEABLE, BUT INTERNAL DIFFERENCES MAY
RESULT IN INFERIOR OCCUPANT PROTECTION.
KJRESTRAINTS 8O - 5
RESTRAINTS (Continued)

WARNING: THE FASTENERS, SCREWS, AND
BOLTS ORIGINALLY USED FOR THE RESTRAINT
SYSTEM COMPONENTS HAVE SPECIAL COATINGS
AND ARE SPECIFICALLY DESIGNED FOR THE
RESTRAINT SYSTEM. THEY MUST NEVER BE
REPLACED WITH ANY SUBSTITUTES. ANY TIME A
NEW FASTENER IS NEEDED, REPLACE IT WITH
THE CORRECT FASTENERS PROVIDED IN THE
SERVICE PACKAGE OR SPECIFIED IN THE
DAIMLERCHRYSLER MOPAR PARTS CATALOG.
WARNING: WHEN A STEERING COLUMN HAS AN
AIRBAG UNIT ATTACHED, NEVER PLACE THE COL-
UMN ON THE FLOOR OR ANY OTHER SURFACE
WITH THE STEERING WHEEL OR AIRBAG UNIT
FACE DOWN.
DIAGNOSIS AND TESTING - SUPPLEMENTAL
RESTRAINT SYSTEM
Proper diagnosis and testing of the supplemental
restraint system components, the PCI data bus, the
data bus message inputs to and outputs from the
ElectroMechanical Instrument Cluster (EMIC), the
Airbag Control Module (ACM), or the Side Impact
Airbag Control Module (SIACM) as well as the
retrieval or erasure of a Diagnostic Trouble Code
(DTC) from the ACM or SIACM requires the use of a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
STANDARD PROCEDURE
STANDARD PROCEDURE - HANDLING
NON-DEPLOYED SUPPLEMENTAL RESTRAINTS
At no time should any source of electricity be per-
mitted near the inflator on the back of a non-de-
ployed airbag or seat belt tensioner. When carrying a
non-deployed airbag, the trim cover or airbag cushion
side of the unit should be pointed away from the
body to minimize injury in the event of an accidental
deployment. If the airbag unit is placed on a bench or
any other surface, the trim cover or airbag cushion
side of the unit should be face up to minimize move-
ment in the event of an accidental deployment. When
handling a non-deployed seat belt tensioner, take
proper care to keep fingers out from under the
retractor cover and away from the seat belt webbing
where it exits from the retractor cover. In addition,
the supplemental restraint system should be dis-
armed whenever any steering wheel, steering col-
umn, seat belt tensioner, driver airbag, passenger
airbag, front impact sensor, side curtain airbag, or
instrument panel components require diagnosis or
service. Failure to observe this warning could result
in accidental airbag deployment and possible per-
sonal injury.
All damaged, faulty or non-deployed airbags and
seat belt tensioners which are replaced on vehicles
are to be handled and disposed of properly. If an air-
bag or seat belt tensioner unit is faulty or damaged
and non-deployed, refer to the Hazardous Substance
Control System for proper disposal. Dispose of all
non-deployed and deployed airbags and seat belt ten-
sioners in a manner consistent with state, provincial,
local and federal regulations.
SUPPLEMENTAL RESTRAINT STORAGE
Airbags and seat belt tensioners must be stored in
their original, special container until they are used
for service. Also, they must be stored in a clean, dry
environment; away from sources of extreme heat,
sparks, and high electrical energy. Always place or
store any airbag on a surface with its trim cover or
airbag cushion side facing up, to minimize movement
in case of an accidental deployment.
STANDARD PROCEDURE - SERVICE AFTER A
SUPPLEMENTAL RESTRAINT DEPLOYMENT
Any vehicle which is to be returned to use follow-
ing a supplemental restraint deployment, must have
the deployed restraints replaced. In addition, if the
driver airbag has been deployed, the clockspring
must be replaced. If the passenger airbag is
deployed, the passenger airbag door and both passen-
ger airbag mounting brackets must be replaced. If a
side curtain airbag has been deployed, the complete
8O - 6 RESTRAINTSKJ
RESTRAINTS (Continued)

airbag unit, the headliner, as well as the upper A, B,
and C-pillar trim must be replaced. These compo-
nents are not intended for reuse and will be damaged
or weakened as a result of a supplemental restraint
deployment, which may or may not be obvious during
a visual inspection.
On vehicles with an optional sunroof, the sunroof
drain tubes and hoses must be closely inspected fol-
lowing a side curtain airbag deployment. It is also
critical that the mounting surfaces and/or mounting
brackets for the Airbag Control Module (ACM), Side
Impact Airbag Control Module (SIACM), and front
impact sensors be closely inspected and restored to
their original conditions following any vehicle impact
damage. Because the ACM, SIACM, and each front
impact sensor are used by the supplemental restraint
system to monitor or confirm the direction and sever-
ity of a vehicle impact, improper orientation or inse-
cure fastening of these components may cause
airbags not to deploy when required, or to deploy
when not required. All other vehicle components
should be closely inspected following any other sup-
plemental restraint deployment, but are to be
replaced only as required by the extent of the visible
damage incurred.
AIRBAG SQUIB STATUS
Multistage airbags with multiple initiators (squibs)
must be checked to determine that all squibs were
used during the deployment event. The driver and
passenger airbags in this model are deployed by elec-
trical signals generated by the Airbag Control Mod-
ule (ACM) through the driver or passenger squib 1
and squib 2 circuits to the two initiators in the air-
bag inflators. Typically, both initiators are used andall potentially hazardous chemicals are burned dur-
ing an airbag deployment event. However, it is possi-
ble for only one initiator to be used due to an airbag
system fault; therefore, it is always necessary to con-
firm that both initiators have been used in order to
avoid the improper handling or disposal of poten-
tially live pyrotechnic or hazardous materials. The
following procedure should be performed using a
DRBIIItscan tool to verify the status of both airbag
squibs before either deployed airbag is removed from
the vehicle for disposal.
CAUTION: Deployed front airbags having two initia-
tors (squibs) in the airbag inflator may or may not
have live pyrotechnic material within the inflator. Do
not dispose of these airbags unless you are sure of
complete deployment. Refer to the Hazardous Sub-
stance Control System for proper disposal proce-
dures. Dispose of all non-deployed and deployed
airbags in a manner consistent with state, provin-
cial, local, and federal regulations.
(1) Be certain that the DRBIIItscan tool contains
the latest version of the proper DRBIIItsoftware.
Connect the DRBIIItto the 16-way Data Link Con-
nector (DLC). The DLC is located on the driver side
lower edge of the instrument panel, outboard of the
steering column.
(2) Turn the ignition switch to the On position.
(3) Using the DRBIIIt, read and record the active
(current) Diagnostic Trouble Code (DTC) data.
Using the active DTC information, refer to theAir-
bag Squib Statustable to determine the status of
both driver and/or passenger airbag squibs.
AIRBAG SQUIB STATUS
IF the Active DTC is: Conditions Squib Status
Driver or Passenger Squib 1 openANDthe stored DTC minutes for both
Driver or Passenger squibs are within 15
minutes of each otherBoth Squib 1 and 2
were used.
Driver or Passenger Squib 2 open
Driver or Passenger Squib 1 openANDthe stored DTC minutes for Driver or
Passenger Squib 2 open is GREATER than
the stored DTC minutes for Driver or
Passenger Squib 1 by 15 minutes or moreSquib 1 was used;
Squib 2 is live.
Driver or Passenger Squib 2 open
Driver or Passenger Squib 1 openANDthe stored DTC minutes for Driver or
Passenger Squib 1 open is GREATER than
the stored DTC minutes for Driver or
Passenger Squib 2 by 15 minutes or moreSquib 1 is live; Squib
2 was used.
Driver or Passenger Squib 2 open
Driver or Passenger Squib 1 openANDDriver or Passenger Squib 2 open is
NOT an active codeSquib 1 was used;
Squib 2 is live.
Driver or Passenger Squib 2 openANDDriver or Passenger Squib 1 open is
NOT an active codeSquib 1 is live; Squib
2 was used.
KJRESTRAINTS 8O - 7
RESTRAINTS (Continued)

(1) During the following test, the battery negative
cable remains disconnected and isolated, as it was
during the airbag component removal and installa-
tion procedures.
(2) Be certain that the DRBIIItscan tool contains
the latest version of the proper DRBIIItsoftware.
Connect the DRBIIItto the 16-way Data Link Con-
nector (DLC). The DLC is located on the driver side
lower edge of the instrument panel, outboard of the
steering column (Fig. 5).
(3) Turn the ignition switch to the On position and
exit the vehicle with the DRBIIItscan tool.
(4) Check to be certain that nobody is in the vehi-
cle, then reconnect the battery negative cable.
(5) Using the DRBIIIt, read and record the active
(current) Diagnostic Trouble Code (DTC) data.
(6) Next, use the DRBIIItto read and record any
stored (historical) DTC data.
(7) If any DTC is found in Step 5 or Step 6, refer
to the appropriate diagnostic information.
(8) Use the DRBIIItto erase the stored DTC data.
If any problems remain, the stored DTC data will not
erase. Refer to the appropriate diagnostic informa-
tion to diagnose any stored DTC that will not erase.
If the stored DTC information is successfully erased,
go to Step 9.
(9) Turn the ignition switch to the Off position for
about fifteen seconds, and then back to the On posi-
tion. Observe the airbag indicator in the instrument
cluster. It should illuminate for six to eight seconds,and then go out. This indicates that the supplemen-
tal restraint system is functioning normally and that
the repairs are complete. If the airbag indicator fails
to light, or lights and stays on, there is still an active
supplemental restraint system fault or malfunction.
Refer to the appropriate diagnostic information to
diagnose the problem.
AIRBAG CONTROL MODULE
DESCRIPTION
The Airbag Control Module (ACM) is also some-
times referred to as the Occupant Restraint Control-
ler (ORC) (Fig. 6). The ACM is secured with two long
screws within a tray-like stamped steel mounting
bracket welded onto the top of the floor panel trans-
mission tunnel forward of the instrument panel cen-
ter support bracket and below the instrument panel
center stack in the passenger compartment of the
vehicle.
Concealed within a hollow in the center of the die
cast aluminum ACM housing is the electronic cir-
cuitry of the ACM which includes a microprocessor,
an electronic impact sensor, an electromechanical saf-
ing sensor, and an energy storage capacitor. A
stamped metal cover plate is secured to the bottom of
the ACM housing with four screws to enclose and
protect the internal electronic circuitry and compo-
nents. An arrow cast into the top of the ACM housing
near the front provides a visual verification of the
proper orientation of the unit, and should always be
pointed toward the front of the vehicle.
Fig. 5 16-Way Data Link Connector - Typical
1 - 16±WAY DATA LINK CONNECTOR
2 - BOTTOM OF INSTRUMENT PANEL
Fig. 6 Airbag Control Module
1 - AIRBAG CONTROL MODULE
2 - ORIENTATION ARROW
3 - CONNECTOR RECEPTACLES
4 - MOUNTING HOLES
5 - GROUND LUG
KJRESTRAINTS 8O - 9
RESTRAINTS (Continued)

The ACM housing also has an integral ground lug
with a tapped hole that protrudes from the lower left
rear corner of the unit. This lug provides a case
ground to the ACM when a ground screw is installed
through the left side of the mounting bracket. Two
molded plastic electrical connector receptacles exit
the right side of the ACM housing. The smaller of the
two receptacles contains twelve terminal pins, while
the larger one contains twenty-three. These terminal
pins connect the ACM to the vehicle electrical system
through two dedicated take outs and connectors of
the instrument panel wire harness.
A molded rubber protective cover is installed
loosely over the ACM to protect the unit from con-
densation or coolant leaking from a damaged or
faulty heater-air conditioner unit housing. An inte-
gral flange on the left side of the cover is secured to
the floor panel transmission tunnel with a short
piece of double-faced tape as an assembly aid during
the manufacturing process, but this tape does not
require replacement following service removal.
The impact sensor and safing sensor internal to
the ACM are calibrated for the specific vehicle, and
are only serviced as a unit with the ACM. The ACM
cannot be repaired or adjusted and, if damaged or
faulty, it must be replaced. The ACM cover is avail-
able for separate service replacement.
OPERATION
The microprocessor in the Airbag Control Module
(ACM) contains the front supplemental restraint sys-
tem logic circuits and controls all of the front supple-
mental restraint system components. The ACM uses
On-Board Diagnostics (OBD) and can communicate
with other electronic modules in the vehicle as well
as with the DRBIIItscan tool using the Programma-
ble Communications Interface (PCI) data bus net-
work. This method of communication is used for
control of the airbag indicator in the ElectroMechani-
cal Instrument Cluster (EMIC) and for supplemental
restraint system diagnosis and testing through the
16-way data link connector located on the driver side
lower edge of the instrument panel. (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER/AIRBAG
INDICATOR - OPERATION).
The ACM microprocessor continuously monitors all
of the front supplemental restraint system electrical
circuits to determine the system readiness. If the
ACM 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 the duration of the current ignition
switch cycle, while a stored fault causes a DTC to be
stored in memory by the ACM. For some DTCs, if afault does not recur for a number of ignition cycles,
the ACM will automatically erase the stored DTC.
For other internal faults, the stored DTC is latched
forever.
On models equipped with optional side curtain air-
bags, the ACM communicates with both the left and
right Side Impact Airbag Control Modules (SIACM)
over the PCI data bus. The SIACM notifies the ACM
when it has detected a monitored system fault and
stored a DTC in memory for its respective side cur-
tain airbag system, and the ACM sets a DTC and
controls the airbag indicator operation accordingly.
The ACM also monitors a Hall effect-type seat belt
switch located in the buckle of each front seat belt to
determine whether the seatbelts are buckled, and
provides an input to the EMIC over the PCI data bus
to control the seatbelt indicator operation based upon
the status of the driver side front seat belt switch.
The ACM 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 ACM has a case
ground through a lug on the bottom of the ACM
housing that is secured with a ground screw to the
left side of the ACM mounting bracket. The ACM
also receives a power ground through a ground cir-
cuit and take out of the instrument panel wire har-
ness. This take out has a single eyelet terminal
connector that is secured by a second ground screw
to the left side of the ACM mounting bracket. These
connections allow the ACM to be operational when-
ever the ignition switch is in the Start or On posi-
tions. The ACM 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
airbags for up to one second following a battery dis-
connect or failure. The purpose of the capacitor is to
provide backup supplemental restraint system pro-
tection in case there is a loss of battery current sup-
ply to the ACM during an impact.
Two sensors are contained within the ACM, an
electronic impact sensor and a safing sensor. The
ACM also monitors inputs from two remote front
impact sensors located on the back of the right and
left vertical members of the radiator support near
the front of the vehicle. The electronic impact sensors
are accelerometers that sense the rate of vehicle
deceleration, which provides verification of the direc-
tion and severity of an impact. The safing sensor is
an electromechanical sensor within the ACM that
provides an additional logic input to the ACM micro-
processor. The safing sensor is a normally open
switch that is used to verify the need for an airbag
deployment by detecting impact energy of a lesser
8O - 10 RESTRAINTSKJ
AIRBAG CONTROL MODULE (Continued)

a molded plastic turn signal cancel cam with a single
lobe that is integral to the rotor. Within the plastic
case and wound around the rotor spool is a long rib-
bon-like tape that consists of several thin copper wire
leads sandwiched between two thin plastic mem-
branes. The outer end of the tape terminates at the
connector receptacles that face the instrument panel,
while the inner end of the tape terminates at the pig-
tail wires and connector receptacle on the hub of the
clockspring rotor that face the steering wheel.
Service replacement clocksprings are shipped pre-
centered and with a molded plastic shield that snaps
onto the rotor over the release button. The release
button secures the centered clockspring rotor to the
clockspring case and the shield prevents the release
button from being inadvertently depressed during
shipment and handling, but the shield must be
removed from the clockspring after it is installed on
the steering column. (Refer to 8 - ELECTRICAL/RE-
STRAINTS/CLOCKSPRING - STANDARD PROCE-
DURE - CLOCKSPRING CENTERING).
The clockspring cannot be repaired. If the clock-
spring is faulty, damaged, or if the driver airbag has
been deployed, the clockspring must be replaced.
OPERATION
The clockspring is a mechanical electrical circuit
component that is used to provide continuous electri-
cal continuity between the fixed instrument panel
wire harness and the electrical components mounted
on or in the rotating steering wheel. On this model
the rotating electrical components include the driver
airbag, the horn switch, the speed control switches,and the remote radio switches, if the vehicle is so
equipped. The clockspring case is positioned and
secured to the upper steering column housing near
the top of the steering column. The connector recep-
tacles on the tail of the fixed clockspring case connect
the clockspring to the vehicle electrical system
through two take outs with connectors from the
instrument panel wire harness. The clockspring rotor
is movable and is keyed by the tower formation that
is molded onto the upper surface of the rotor hub to
an opening that is cast into the steering wheel arma-
ture. Rubber bumper blocks on either side of the
clockspring tower formation eliminate contact noise
between the clockspring tower and the steering
wheel. The lobe of the turn signal cancel cam on the
lower surface of the clockspring rotor hub contacts a
turn signal cancel actuator of the multi-function
switch to provide automatic turn signal cancellation.
The yellow-sleeved pigtail wires on the upper surface
of the clockspring rotor connect the clockspring to the
driver airbag, while a steering wheel wire harness
connects the connector receptacle on the upper sur-
face of the clockspring rotor to the horn switch and,
if the vehicle is so equipped, to the optional speed
control switches and remote radio switches on the
steering wheel.
Like the clockspring in a timepiece, the clockspring
tape has travel limits and can be damaged by being
wound too tightly during full stop-to-stop steering
wheel rotation. To prevent this from occurring, the
clockspring is centered when it is installed on the
steering column. Centering the clockspring indexes
the clockspring tape to the movable steering compo-
nents so that the tape can operate within its
designed travel limits. However, if the clockspring is
removed from the steering column or if the steering
shaft is disconnected from the steering gear, the
clockspring spool can change position relative to the
movable steering components and must be re-cen-
tered following completion of the service or the tape
may be damaged. Service replacement clocksprings
are shipped pre-centered and with a plastic shield
installed over the clockspring release button. This
shield should not be removed and the release button
should not be depressed until the clockspring has
been installed on the steering column. If the release
button is depressed before the clockspring is installed
on a steering column, the clockspring centering pro-
cedure must be performed. (Refer to 8 - ELECTRI-
CAL/RESTRAINTS/CLOCKSPRING - STANDARD
PROCEDURE - CLOCKSPRING CENTERING).
STANDARD PROCEDURE - CLOCKSPRING
CENTERING
The clockspring is designed to wind and unwind
when the steering wheel is rotated, but is only
Fig. 11 Clockspring Latches
1 - CASE
2 - LATCH (2)
3 - ROTOR
4 - CANCEL CAM
5 - LOWER CONNECTOR RECEPTACLE (2)
8O - 14 RESTRAINTSKJ
CLOCKSPRING (Continued)

designed to rotate the same number of turns (about
five complete rotations) as the steering wheel can be
turned from stop to stop. Centering the clockspring
indexes the clockspring tape to other steering compo-
nents so that it can operate within its designed
travel limits. The rotor of a centered clockspring can
be rotated two and one-half turns in either direction
from the centered position, without damaging the
clockspring tape.
However, if the clockspring is removed for service
or if the steering column is disconnected from the
steering gear, the clockspring tape can change posi-
tion relative to the other steering components. The
clockspring must then be re-centered following com-
pletion of such service or the clockspring tape may be
damaged. Service replacement clocksprings are
shipped pre-centered, with the release button
engaged (raised) and a molded plastic shield installed
over the release button. This release button should
not be disengaged and the shield should not be
removed until the clockspring has been installed on
the steering column. If the release button is disen-
gaged before the clockspring is installed on a steering
column, the clockspring centering procedure must be
performed.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
NOTE: Before starting this procedure, be certain to
turn the steering wheel until the front wheels are in
the straight-ahead position.
(1) Place the front wheels in the straight-ahead
position.
(2) Remove the clockspring from the steering col-
umn. (Refer to 8 - ELECTRICAL/RESTRAINTS/
CLOCKSPRING - REMOVAL).
(3) Depress the release button (Fig. 12).(4) Keeping the release button depressed, rotate
the clockspring rotor clockwise to the end of its
travel.Do not apply excessive torque.
(5) From the end of the clockwise travel, rotate the
rotor about two and one-half turns counterclockwise,
then release the release button. The clockspring
tower formation with the pigtail wires for the driver
airbag and the connector receptacle for the steering
wheel wire harness should end up at the top, the
blue roller should be visible through the inspection
window, and the printed arrow on the label of the
clockspring rotor should be aligned with the arrow
molded into the clockspring case. The clockspring is
now centered.
(6) The front wheels should still be in the straight-
ahead position. Reinstall the clockspring onto the
steering column. (Refer to 8 - ELECTRICAL/RE-
STRAINTS/CLOCKSPRING - INSTALLATION).
REMOVAL
The clockspring cannot be repaired. It must be
replaced if faulty or damaged, or if the driver airbag
has been deployed.
Fig. 12 Clockspring Centering
1 - ROTOR LABEL
2 - RELEASE BUTTON
3 - ALIGNMENT ARROWS
4 - INSPECTION WINDOW
KJRESTRAINTS 8O - 15
CLOCKSPRING (Continued)