2002 JEEP LIBERTY Body

in parallel with the IC where the two pigtail wire
leads connect to the IC pins.
The seat belt switch cannot be adjusted or repaired
and, if faulty or damaged, the entire seat belt buckle-
half unit must be replaced.
OPERATION
The seat belt switches are designed to provide a
status signal to the seat belt switch sense inputs of
the Airbag Control Module (ACM) indicating whether
the front seat belts are fastened. The ACM uses the
seat belt switch inputs as a factor in determining
what level of force with which it should deploy the
multistage driver and passenger airbags. In addition,
the ACM sends electronic messages to the ElectroMe-
chanical Instrument Cluster (EMIC) to control the
seat belt indicator based upon the status of the
driver side front seat belt switch. A spring-loaded
plastic slide with a small, enclosed permanent mag-
net is integral to the buckle latch mechanism. When
a seat belt tip-half is inserted and latched into the
seat belt buckle, the slide is pushed downward and
into close proximity of the Hall Effect Integrated Cir-
cuit (IC) chip within the buckle, which induces a cur-
rent within the chip. The chip provides this induced
current as an output to the ACM, which monitors the
current to determine the status of the front seat
belts. When the seat belt is unbuckled, the spring-
loaded slide and permanent magnet move upward
and away from the IC, causing the output current
from the seat belt switch to be reduced.
The seat belt switch receives a supply current from
the ACM, and the ACM senses the status of the front
seat belts through its pigtail wire connection to the
seat wire harness. The ACM also monitors the condi-
tion of the seat belt switch circuits through circuit
resistance created by the diagnostic resistor. The
ACM will illuminate the airbag indicator in the
EMIC and store a Diagnostic Trouble Code (DTC) for
any fault that is detected in either seat belt switch
circuit. For proper diagnosis of the seat belt switches,
a DRBIIItscan tool is required. Refer to the appro-
priate diagnostic information.
SEAT BELT TENSIONER
DESCRIPTION
A driver side seat belt tensioner supplements the
driver airbag system for all versions of this model
(Fig. 34). The seat belt tensioner is integral to the
driver side front seat belt and retractor unit, which is
secured to the B-pillar on the left side of the vehicle.
The retractor is concealed beneath the molded plastic
B-pillar trim. The seat belt tensioner consists prima-
rily of a molded plastic tensioner housing, a tubularmetal piston housing, a piston, a short rack gear, a
set of pinion gears, a pyrotechnically activated gas
generator, and a short pigtail wire. All of these com-
ponents are located on one side of the retractor spool
on the outside of the retractor housing. The seat belt
tensioner is controlled by the Airbag Control Module
(ACM) and is connected to the vehicle electrical sys-
tem through a dedicated take out of the body wire
harness by a keyed and latching molded plastic con-
nector insulator to ensure a secure connection.
The seat belt tensioner cannot be repaired and, if
faulty or damaged, the entire driver side front seat
belt and retractor unit must be replaced. The seat
belt tensioner is not intended for reuse and must be
replaced following a deployment. A locked retractor
that will not allow the seat belt webbing to be
retracted or extracted is a sure indication that the
seat belt tensioner has been deployed and requires
replacement. (Refer to 8 - ELECTRICAL/RE-
STRAINTS/FRONT SEAT BELT & RETRACTOR -
REMOVAL).
OPERATION
The seat belt tensioner is deployed by a signal gen-
erated by the Airbag Control Module (ACM) through
the driver seat belt tensioner line 1 and line 2 (or
squib) circuits. When the ACM sends the proper elec-
trical signal to the tensioner, the electrical energy
generates enough heat to initiate a small pyrotechnic
gas generator. The gas generator is installed in one
end of the tubular metal piston housing, which con-
tains a piston and a small rack gear. As the gas
expands, it pushes the piston and the rack gear
Fig. 34 Seat Belt Tensioner
1 - RETRACTOR
2 - TENSIONER HOUSING
3 - PISTON HOUSING
4 - PIGTAIL WIRE
5 - GAS GENERATOR
8O - 36 RESTRAINTSKJ
SEAT BELT SWITCH (Continued)

through the tube. The rack gear engages a pinion
gear that drives a gear set in the tensioner housing,
which drives the seat belt retractor spool causing the
slack to be removed from the driver side front seat
belt. Removing excess slack from the driver side front
seat belt not only keeps the occupant properly posi-
tioned for an airbag deployment following a frontal
impact of the vehicle, but also helps to reduce inju-
ries that the occupant of the driver side front seat
might experience in these situations as a result of a
harmful contact with the steering wheel and/or steer-
ing column. Also, the seat belt tensioner has a tor-
sion bar mechanism that is designed to deform in
order to control the loading being applied to the occu-
pant of the driver side front seat by the seat belt dur-
ing a frontal impact, further reducing the potential
for occupant injuries.
The ACM monitors the condition of the seat belt
tensioner through circuit resistance, and will illumi-
nate the airbag indicator in the ElectroMechanical
Instrument Cluster (EMIC) and store a Diagnostic
Trouble Code (DTC) for any fault that is detected.
For proper diagnosis of the seat belt tensioner, a
DRBIIItscan tool is required. Refer to the appropri-
ate diagnostic information.
SEAT BELT TURNING LOOP
ADJUSTER
REMOVAL
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.
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 BELTTHAT 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 MOPAR PARTS CATALOG.
(1) Disconnect and isolate the battery negative
cable. Wait two minutes for the system capacitor to
discharge before further service.
(2) Unsnap and lift the trim cover to access the
nut that secures the front seat belt turning loop to
the height adjuster on the upper B-pillar.
(3) Remove the nut that secures the seat belt turn-
ing loop to the height adjuster stud on the upper
B-pillar.
(4) Remove the seat belt turning loop from the
height adjuster stud.
(5) Remove the upper trim from the inside of the
B-pillar. (Refer to 23 - BODY/INTERIOR/B-PILLAR
UPPER TRIM - REMOVAL).
(6) Remove the screw that secures the seat belt
turning loop adjuster to the upper B-pillar (Fig. 35).
(7) Pull the upper end of the turning loop adjuster
away from the B-pillar far enough to disengage the
hooks on the lower end of the adjuster from the slots
in the B-pillar.
(8) Remove the seat belt turning loop adjuster
from the B-pillar.
Fig. 35 Seat Belt Turning Loop Adjuster Remove/
Install
1 - SCREW
2 - B-PILLAR
3 - ADJUSTER
KJRESTRAINTS 8O - 37
SEAT BELT TENSIONER (Continued)

INSTALLATION
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.
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 MOPAR PARTS CATALOG.
(1) Position the seat belt turning loop adjuster to
the B-pillar (Fig. 35).
(2) Engage the hooks on the lower end of the
adjuster into the slots in the B-pillar.
(3) Tilt the upper end of the turning loop adjuster
up into position against the B-pillar.
(4) Install and tighten the screw that secures the
seat belt turning loop adjuster to the upper B-pillar.
Tighten the screw to 34 N´m (25 ft. lbs.).
(5) Reinstall the upper trim onto the inside of the
B-pillar. (Refer to 23 - BODY/INTERIOR/B-PILLAR
UPPER TRIM - INSTALLATION).
(6) Position the seat belt turning loop onto the
height adjuster stud on the upper B-pillar.
(7) Install and tighten the nut that secures the
seat belt turning loop to the height adjuster stud.
Tighten the nut to 34 N´m (25 ft. lbs.).(8) Fold and snap the trim cover back into place to
conceal the nut that secures the front seat belt turn-
ing loop to the height adjuster on the upper B-pillar.
(9) Reconnect the battery negative cable.
SIDE CURTAIN AIRBAG
DESCRIPTION
Optional side curtain airbags are available for this
model when it is also equipped with dual front air-
bags. These airbags are passive, inflatable, Supple-
mental Restraint System (SRS) components, and
vehicles with this equipment can be readily identified
by a molded identification trim button with the ªSRS
- AIRBAGº logo located on the headliner above each
B-pillar (Fig. 36). This system is designed to reduce
injuries to the vehicle occupants in the event of a
side impact collision.
Vehicles equipped with side curtain airbags have
two individually controlled curtain airbag units.
These airbag units are concealed and mounted above
the headliner where they are each secured to one of
the roof side rails (Fig. 37). Each folded airbag cush-
ion is contained within a long extruded plastic chan-
nel that extends along the roof rail from the A-pillar
at the front of the vehicle to just behind the C-pillar
at the rear of the vehicle. The channel is secured
with plastic push-in fasteners to the roof rail. A
tether extends down the A-pillar from the front of the
airbag cushion, where it is retained to the pillar with
plastic push-in routing clips and it is secured to the
base of the A-pillar near the belt line with a screw.
The hybrid-type inflator for each airbag is secured
to the roof rail at the rear of the airbag unit between
the C-pillar and the D-pillar, and is connected to the
airbag cushion by a long tubular manifold. The
bracket holding the inflator and three other brackets
holding the manifold are secured to the roof rail with
Fig. 36 SRS Logo
8O - 38 RESTRAINTSKJ
SEAT BELT TURNING LOOP ADJUSTER (Continued)

screws. A two-wire pigtail harness is routed forward
from the airbag inflator through a trough along the
top of the plastic airbag channel on the roof rail and
down the B-pillar, where it is retained by three rout-
ing clips. The pigtail harness is connected to a take
out and connector of the body wire harness on the
B-pillar, which connects to the respective right or left
Side Impact Airbag Control Module (SIACM) on the
sill panel at the base of the B-pillar.
The side curtain airbag unit cannot be adjusted or
repaired and must be replaced if deployed, faulty, or
in any way damaged. Once a side curtain airbag has
been deployed, the complete airbag unit, the head-
liner, the upper A, B, and C-pillar trim, and all other
visibly damaged components must be replaced.
OPERATION
Each side curtain airbag is deployed individually by
an electrical signal generated by the left or right Side
Impact Airbag Control Module (SIACM) to which it is
connected through left or right curtain airbag line 1 and
line 2 (or squib) circuits. The hybrid-type inflatorassembly for each airbag contains a small canister of
highly compressed helium gas. When the SIACM sends
the proper electrical signal to the airbag inflator, the
electrical energy creates enough heat to ignite chemical
pellets within the inflator. Once ignited, these chemicals
burn rapidly and produce the pressure necessary to rup-
ture a containment disk in the helium gas canister. The
inflator and helium gas canister are sealed and con-
nected to a tubular manifold so that all of the released
gas is directed into the folded curtain airbag cushion,
causing the cushion to inflate.
As the airbag cushion inflates it will drop down
from the roof rail between the edge of the headliner
and the side glass/body pillars to form a curtain-like
cushion to protect the vehicle occupants during a side
impact collision. The front tether keeps the front por-
tion of the bag taut, thus ensuring that the bag will
deploy in the proper position. Following the airbag
deployment, the airbag cushion quickly deflates by
venting the helium gas through the loose weave of
the cushion fabric, and the deflated cushion hangs
down loosely from the roof rail.
Fig. 37 Side Curtain Airbag
1 - INFLATOR
2 - MANIFOLD
3 - CHANNEL
4 - TETHER5 - PIGTAIL WIRE RETAINER (3)
6 - PUSH-IN FASTENER (4)
7 - BRACKET (3)
KJRESTRAINTS 8O - 39
SIDE CURTAIN AIRBAG (Continued)

REMOVAL
The following procedure is for replacement of a
faulty or damaged side curtain airbag. If the side
curtain airbag has been deployed, review the recom-
mended procedures for service after a supplemental
restraint deployment before removing the airbag
from the vehicle. (Refer to 8 - ELECTRICAL/RE-
STRAINTS - STANDARD PROCEDURE - SERVICE
AFTER A SUPPLEMENTAL RESTRAINT DEPLOY-
MENT).
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.
WARNING: WHEN REMOVING A DEPLOYED AIR-
BAG, RUBBER GLOVES, EYE PROTECTION, AND A
LONG-SLEEVED SHIRT SHOULD BE WORN. THERE
MAY BE DEPOSITS ON THE AIRBAG UNIT AND
OTHER INTERIOR SURFACES. IN LARGE DOSES,
THESE DEPOSITS MAY CAUSE IRRITATION TO THE
SKIN AND EYES.
WARNING: USE EXTREME CARE TO PREVENT ANY
FOREIGN MATERIAL FROM ENTERING THE SIDE
CURTAIN AIRBAG, OR BECOMING ENTRAPPED
BETWEEN THE SIDE CURTAIN AIRBAG CUSHION
AND THE HEADLINER. FAILURE TO OBSERVE THIS
WARNING COULD RESULT IN OCCUPANT INJURIES
UPON AIRBAG DEPLOYMENT.(1) Disconnect and isolate the battery negative
cable. Wait two minutes for the system capacitor to
discharge before further service.
(2) Remove the lower trim from the inside of the
B-pillar. (Refer to 23 - BODY/INTERIOR/B-PILLAR
LOWER TRIM - REMOVAL).
(3) Remove the headliner from the vehicle. (Refer
to 23 - BODY/INTERIOR/HEADLINER - REMOV-
AL).
(4) Remove the screw that secures the side curtain
airbag tether retainer to the base of the A-pillar near
the belt line (Fig. 38).
Fig. 38 Side Curtain Airbag Tether Remove/Install
1 - A-PILLAR
2 - CLIP (2)
3 - TETHER
4 - RETAINER (1)
5 - SCREW (1)
8O - 40 RESTRAINTSKJ
SIDE CURTAIN AIRBAG (Continued)

(5) Disengage the two side curtain airbag tether
plastic retainer clips from the A-pillar.
(6) Disconnect the side curtain airbag pigtail wire
connector from the body wire harness connector near
the base of the B-pillar (Fig. 39).
(7) Disengage the three side curtain airbag pigtail
wire retainer clips from the B-pillar.
(8) Remove the three screws that secure the side
curtain airbag manifold tube brackets to the U-nuts
in the roof rail (Fig. 40) and (Fig. 41).
(9) Remove the two screws that secure the side
curtain airbag inflator bracket to the U-nuts in the
roof rail (Fig. 42).
(10) Grasp the extruded plastic side curtain airbag
channel firmly and pull it straight away from the
roof rail far enough to disengage all four plastic
push-in fasteners that secure it.
(11) Remove the side curtain airbag from the vehi-
cle as a unit.
INSTALLATION
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.
WARNING: WHEN REMOVING A DEPLOYED AIR-
BAG, RUBBER GLOVES, EYE PROTECTION, AND A
LONG-SLEEVED SHIRT SHOULD BE WORN. THERE
MAY BE DEPOSITS ON THE AIRBAG UNIT AND
OTHER INTERIOR SURFACES. IN LARGE DOSES,
THESE DEPOSITS MAY CAUSE IRRITATION TO THE
SKIN AND EYES.
Fig. 39 Side Curtain Airbag Pigtail Wire Remove/
Install
1 - RETAINER (3)
2 - B-PILLAR
3 - WIRE HARNESS CONNECTOR
4 - PIGTAIL WIRE
Fig. 40 Side Curtain Airbag (Front) Remove/Install
1 - ROOF PANEL
2 - PIGTAIL WIRE
3 - B-PILLAR
4 - PUSH-IN FASTENER (4)
5 - RETAINER
6 - CHANNEL
7 - A-PILLAR
8 - TETHER
9 - SCREW (3)
10 - U-NUT (5)
KJRESTRAINTS 8O - 41
SIDE CURTAIN AIRBAG (Continued)

WARNING: USE EXTREME CARE TO PREVENT ANY
FOREIGN MATERIAL FROM ENTERING THE SIDE
CURTAIN AIRBAG, OR BECOMING ENTRAPPED
BETWEEN THE SIDE CURTAIN AIRBAG CUSHION
AND THE HEADLINER. FAILURE TO OBSERVE THIS
WARNING COULD RESULT IN OCCUPANT INJURIES
UPON AIRBAG DEPLOYMENT.
(1) Position the side curtain airbag into the vehicle
as a unit.
(2) Align all four plastic push-in fasteners that
secure the extruded plastic side curtain airbag chan-
nel with their holes in the roof side rail and push
them straight into the roof rail until they are fully
seated (Fig. 40) and (Fig. 41).
(3) Install and tighten the upper screw that
secures the side curtain airbag inflator bracket to the
U-nut in the roof rail, followed by the lower screw
(Fig. 42). Tighten the screws to 12 N´m (105 in. lbs.).
(4) Working from the rear of the vehicle to the
front, install and tighten each of the three screws
that secure the side curtain airbag manifold tube
brackets to the U-nuts in the roof rail. Tighten the
screws to 12 N´m (105 in. lbs.).(5) Route the side curtain airbag pigtail wire
through the trough along the top of the extruded
plastic airbag channel on the roof side rail, then
between the channel and the body down the B-pillar.
NOTE: Be certain that the side curtain airbag pigtail
wire is routed behind the airbag channel, between
the channel and the body above the B-pillar.
(6) Engage the three side curtain airbag pigtail
wire retainer clips into the B-pillar (Fig. 39).
(7) Reconnect the side curtain airbag pigtail wire
connector to the body wire harness connector near
the base of the B-pillar.
(8) Engage the two side curtain airbag tether plas-
tic retainer clips into the A-pillar (Fig. 38).
(9) Install and tighten the screw that secures the
side curtain airbag tether retainer to the base of the
A-pillar near the belt line. Tighten the screw to 14
N´m (120 in. lbs.).
Fig. 41 Side Curtain Airbag (Rear) Remove/Install
1 - ROOF PANEL
2 - SCREW (3)
3 - U-NUT (5)
4 - PIGTAIL WIRE
5 - MANIFOLD
6 - C-PILLAR
7 - PUSH-IN FASTENER (4)
8 - CHANNEL
Fig. 42 Side Curtain Airbag Inflator Remove/Install
1 - U-NUT (5)
2 - ROOF PANEL
3 - INFLATOR
4 - C-PILLAR
5 - SCREW (2)
6 - MANIFOLD
7 - PIGTAIL WIRE
8 - BRACKET
8O - 42 RESTRAINTSKJ
SIDE CURTAIN AIRBAG (Continued)

(10) Reinstall the headliner into the vehicle. (Refer
to 23 - BODY/INTERIOR/HEADLINER - INSTALLA-
TION).
(11) Reinstall the lower trim onto the inside of the
B-pillar. (Refer to 23 - BODY/INTERIOR/B-PILLAR
LOWER TRIM - INSTALLATION).
(12) Do not reconnect the battery negative cable at
this time. The airbag system verification test proce-
dure should be performed following service of any
supplemental restraint system component. (Refer to
8 - ELECTRICAL/RESTRAINTS - STANDARD PRO-
CEDURE - VERIFICATION TEST).
SIDE IMPACT AIRBAG
CONTROL MODULE
DESCRIPTION
On vehicles equipped with the optional side curtain
airbags, a Side Impact Airbag Control Module
(SIACM) and its mounting bracket are secured with
four screws to the sill panel at the base of each B-pil-
lar behind the lower B-pillar trim (Fig. 43). Con-
cealed within a hollow in the center of the die cast
aluminum SIACM housing is the electronic circuitry
of the SIACM which includes a microprocessor and
an electronic impact sensor. The SIACM housing is
secured to a stamped steel mounting bracket, which
is unique for the right or left side application of this
component. The SIACM should never be removed
from its mounting bracket. The housing also receives
a case ground through this mounting bracket when it
is secured to the vehicle. A molded plastic electrical
connector receptacle that exits the top of the SIACMhousing connects the unit to the vehicle electrical
system through a dedicated take out and connector of
the body wire harness. Both the SIACM housing and
its electrical connection are sealed to protect the
internal electronic circuitry and components against
moisture intrusion.
The impact sensor internal to the SIACM is cali-
brated for the specific vehicle, and is only serviced as
a unit with the SIACM. The SIACM cannot be
repaired or adjusted and, if damaged or faulty, it
must be replaced.
OPERATION
The microprocessor in the Side Impact Airbag Con-
trol Module (SIACM) contains the side curtain airbag
system logic circuits and controls all of the features
of only the side curtain airbag mounted on the same
side of the vehicle as the SIACM. The SIACM 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 by the
SIACM to communicate with the Airbag Control
Module (ACM) and for supplemental restraints sys-
tem diagnosis and testing through the 16-way data
link connector located on the driver side lower edge
of the instrument panel. The ACM communicates
with both the left and right SIACM over the PCI
data bus.
The SIACM microprocessor continuously monitors
all of the side curtain airbag electrical circuits to
determine the system readiness. If the SIACM
detects a monitored system fault, it sets an active
and stored Diagnostic Trouble Code (DTC) and sends
electronic messages to the ACM over the PCI data
bus. The ACM will respond by sending an electronic
message to the EMIC to turn on the airbag indicator,
and by storing a DTC that will indicate whether the
left or the right SIACM has stored the DTC that ini-
tiated the airbag indicator illumination. An active
fault only remains for the current ignition switch
cycle, while a stored fault causes a DTC to be stored
in memory by the SIACM. For some DTCs, if a fault
does not recur for a number of ignition cycles, the
SIACM will automatically erase the stored DTC. For
other internal faults, the stored DTC is latched for-
ever.
The SIACM receives battery current on a fused
ignition switch output (run-start) circuit through a
fuse in the Junction Block (JB). The SIACM has a
case ground through its mounting bracket and also
receives a power ground through a ground circuit
and take out of the body wire harness. This take out
has a single eyelet terminal connector that is secured
by a ground screw to the front seat front crossmem-
Fig. 43 Side Impact Airbag Control Module
1 - BRACKET (RIGHT SHOWN)
2 - CONNECTOR RECEPTACLE
3 - SIACM
KJRESTRAINTS 8O - 43
SIDE CURTAIN AIRBAG (Continued)