Electrical JEEP LIBERTY 2002 KJ / 1.G Workshop Manual

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)

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)

(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)

ber beneath the respective right or left front seat.
These connections allow the SIACM to be operational
whenever the ignition switch is in the Start or On
positions. An electronic impact sensor is contained
within the SIACM. The electronic impact sensor is
an accelerometer that senses the rate of vehicle
deceleration, which provides verification of the direc-
tion and severity of an impact. A pre-programmed
decision algorithm in the SIACM microprocessor
determines when the deceleration rate as signaled by
the impact sensor indicates a side impact that is
severe enough to require side curtain airbag protec-
tion. When the programmed conditions are met, the
SIACM sends the proper electrical signals to deploy
the side curtain airbag.
The hard wired inputs and outputs for the SIACM
may be diagnosed and tested using conventional
diagnostic tools and procedures. However, conven-
tional diagnostic methods will not prove conclusive in
the diagnosis of the SIACM, the PCI data bus net-
work, or the electronic message inputs to and outputs
from the SIACM. The most reliable, efficient, and
accurate means to diagnose the SIACM, the PCI data
bus network, and the electronic message inputs to
and outputs from the SIACM requires the use of a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.
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: THE SIDE IMPACT AIRBAG CONTROL
MODULE CONTAINS THE IMPACT SENSOR, WHICH
ENABLES THE SYSTEM TO DEPLOY THE SIDE
CURTAIN AIRBAGS. NEVER STRIKE OR DROP THE
SIDE IMPACT AIRBAG CONTROL MODULE, AS IT
CAN DAMAGE THE IMPACT SENSOR OR AFFECT
ITS CALIBRATION. IF A SIDE IMPACT AIRBAG CON-
TROL MODULE IS ACCIDENTALLY DROPPED DUR-ING SERVICE, THE MODULE MUST BE SCRAPPED
AND REPLACED WITH A NEW UNIT. FAILURE TO
OBSERVE THIS WARNING COULD RESULT IN ACCI-
DENTAL, INCOMPLETE, OR IMPROPER SIDE CUR-
TAIN AIRBAG DEPLOYMENT AND POSSIBLE
OCCUPANT INJURIES.
(1) Adjust the front seat to its most forward posi-
tion for easiest access to the lower B-pillar trim.
(2) Disconnect and isolate the battery negative
cable. Wait two minutes for the system capacitor to
discharge before further service.
(3) Remove the lower trim from the inside of the
B-pillar. (Refer to 23 - BODY/INTERIOR/B-PILLAR
LOWER TRIM - REMOVAL).
(4) Disconnect the body wire harness connector for
the Side Impact Airbag Control Module (SIACM)
from the module connector receptacle (Fig. 44).
(5) Disengage the body wire harness retainer from
the tab on the SIACM mounting bracket.
(6) Remove the four screws that secure the SIACM
mounting bracket to the sill panel at the base of the
B-pillar.
(7) Remove the SIACM and its mounting bracket
from the sill panel as a unit.
Fig. 44 Side Impact Airbag Control Module
Remove/Install
1 - B-PILLAR
2 - WIRE HARNESS CONNECTOR
3 - SIACM
4 - SCREW (4)
8O - 44 RESTRAINTSKJ
SIDE IMPACT AIRBAG CONTROL MODULE (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: THE SIDE IMPACT AIRBAG CONTROL
MODULE CONTAINS THE IMPACT SENSOR, WHICH
ENABLES THE SYSTEM TO DEPLOY THE SIDE
CURTAIN AIRBAGS. NEVER STRIKE OR DROP THE
SIDE IMPACT AIRBAG CONTROL MODULE, AS IT
CAN DAMAGE THE IMPACT SENSOR OR AFFECT
ITS CALIBRATION. IF A SIDE IMPACT AIRBAG CON-
TROL MODULE IS ACCIDENTALLY DROPPED DUR-
ING SERVICE, THE MODULE MUST BE SCRAPPEDAND REPLACED WITH A NEW UNIT. FAILURE TO
OBSERVE THIS WARNING COULD RESULT IN ACCI-
DENTAL, INCOMPLETE, OR IMPROPER SIDE CUR-
TAIN AIRBAG DEPLOYMENT AND POSSIBLE
OCCUPANT INJURIES.
(1) Position the Side Impact Airbag Control Mod-
ule (SIACM) and its mounting bracket to the sill
panel as a unit (Fig. 44).
(2) Loosely install the four screws that secure the
SIACM mounting bracket to the sill panel at the
base of the B-pillar.
(3) Tighten the four screws that secure the SIACM
mounting bracket to the sill panel in the following
sequence: upper front, upper rear, lower front, lower
rear. Tighten the screws to 12 N´m (105 in. lbs.).
(4) Engage the body wire harness retainer to the
tab on the SIACM mounting bracket.
(5) Reconnect the body wire harness connector for
the SIACM to the module connector receptacle.
(6) Reinstall the lower trim onto the inside of the
B-pillar. (Refer to 23 - BODY/INTERIOR/B-PILLAR
LOWER TRIM - INSTALLATION).
(7) 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).
KJRESTRAINTS 8O - 45
SIDE IMPACT AIRBAG CONTROL MODULE (Continued)

A ªtap downº feature is used to decelerate without
disengaging the speed control system. To decelerate
from an existing recorded target speed, momentarily
depress the COAST switch. For each switch activa-
tion, speed will be lowered approximately 1 mph.
OVERSHOOT/UNDERSHOOT
If the vehicle operator repeatedly presses and
releases the SET button with their foot off of the
accelerator (referred to as a ªlift foot setº), the vehicle
may accelerate and exceed the desired set speed by
up to 5 mph (8 km/h). It may also decelerate to less
than the desired set speed, before finally achieving
the desired set speed.
The Speed Control System has an adaptive strat-
egy that compensates for vehicle-to-vehicle variations
in speed control cable lengths. When the speed con-
trol is set with the vehicle operators foot off of the
accelerator pedal, the speed control thinks there is
excessive speed control cable slack and adapts
accordingly. If the ªlift foot setsº are continually used,
a speed control overshoot/undershoot condition will
develop.
To ªunlearnº the overshoot/undershoot condition,
the vehicle operator has to press and release the set
button while maintaining the desired set speed using
the accelerator pedal (not decelerating or accelerat-
ing), and then turning the cruise control switch to
the OFF position (or press the CANCEL button if
equipped) after waiting 10 seconds. This procedure
must be performed approximately 10±15 times to
completely unlearn the overshoot/undershoot condi-
tion.
DIAGNOSIS AND TESTING - ROAD TEST
Perform a vehicle road test to verify reports of
speed control system malfunction. The road testshould include attention to the speedometer. Speed-
ometer operation should be smooth and without flut-
ter at all speeds.
Flutter in the speedometer indicates a problem
which might cause surging in the speed control sys-
tem. The cause of any speedometer problems should
be corrected before proceeding. Refer to Group 8J,
Instrument Cluster for speedometer diagnosis.
If a road test verifies a system problem and the
speedometer operates properly, check for:
²A Diagnostic Trouble Code (DTC). If a DTC
exists, conduct tests per the Powertrain Diagnostic
Procedures service manual.
²A misadjusted brake (stop) lamp switch. This
could also cause an intermittent problem.
²Loose, damaged or corroded electrical connec-
tions at the servo. Corrosion should be removed from
electrical terminals and a light coating of Mopar
MultiPurpose Grease, or equivalent, applied.
²Leaking vacuum reservoir.
²Loose or leaking vacuum hoses or connections.
²Defective one-way vacuum check valve.
²Secure attachment of both ends of the speed con-
trol servo cable.
²Smooth operation of throttle linkage and throttle
body air valve.
²Failed speed control servo. Do the servo vacuum
test.
CAUTION: When test probing for voltage or conti-
nuity at electrical connectors, care must be taken
not to damage connector, terminals or seals. If
these components are damaged, intermittent or
complete system failure may occur.
SPECIFICATIONS
TORQUE - SPEED CONTROL
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Servo Mounting Bracket-to-Servo Nuts 9 - 75
Servo Mounting Bracket-to-Body Bolts 12 - 105
Speed Control Switch Mounting Screws 1.5 - 14
Vacuum Reservoir Mounting Screws 3 - 20
8P - 2 SPEED CONTROLKJ
SPEED CONTROL (Continued)

(6) Slide speed control cable plastic mount towards
right of vehicle to remove cable from throttle body
bracket (Fig. 4).
(7) Remove servo cable from servo. Refer to Servo
Removal/Installation.
INSTALLATION - 3.7L
(1) Install end of cable to speed control servo.
Refer to Servo Removal/Installation.
(2) Slide speed control cable plastic mount into
throttle body bracket.
(3) Install speed control cable connector onto throt-
tle body bellcrank pin (push rearward to snap into
location).
(4) Slide throttle (accelerator) cable plastic mount
into throttle body bracket. Continue sliding until
cable release tab is aligned to hole in throttle body
mounting bracket.
(5) While holding throttle to wide open position,
place throttle cable pin into throttle body bellcrank.
(6) Install air filter resonator box to throttle body.
(7) Connect negative battery cable at battery.
(8) Before starting engine, operate accelerator
pedal to check for any binding.
SERVO
DESCRIPTION
The servo unit consists of a solenoid valve body,
and a vacuum chamber. The solenoid valve body con-
tains three solenoids:²Vacuum
²Vent
²Dump
The vacuum chamber contains a diaphragm with a
cable attached to control the throttle linkage.
OPERATION
The Powertrain Control Module (PCM) controls the
solenoid valve body. The solenoid valve body controls
the application and release of vacuum to the dia-
phragm of the vacuum servo. The servo unit cannot
be repaired and is serviced only as a complete assem-
bly.
Power is supplied to the servo's by the PCM
through the brake switch. The PCM controls the
ground path for the vacuum and vent solenoids.
The dump solenoid is energized anytime it receives
power. If power to the dump solenoid is interrupted,
the solenoid dumps vacuum in the servo. This pro-
vides a safety backup to the vent and vacuum sole-
noids.
The vacuum and vent solenoids must be grounded
at the PCM to operate. When the PCM grounds the
vacuum servo solenoid, the solenoid allows vacuum
to enter the servo and pull open the throttle plate
using the cable. When the PCM breaks the ground,
the solenoid closes and no more vacuum is allowed to
enter the servo. The PCM also operates the vent sole-
noid via ground. The vent solenoid opens and closes a
passage to bleed or hold vacuum in the servo as
required.
The PCM duty cycles the vacuum and vent sole-
noids to maintain the set speed, or to accelerate and
decelerate the vehicle. To increase throttle opening,
the PCM grounds the vacuum and vent solenoids. To
decrease throttle opening, the PCM removes the
grounds from the vacuum and vent solenoids. When
the brake is released, if vehicle speed exceeds 30
mph to resume, 35 mph to set, and the RES/ACCEL
switch has been depressed, ground for the vent and
vacuum circuits is restored.
REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Disconnect vacuum line at servo (Fig. 5).
(3) Disconnect electrical connector at servo (Fig. 5).
(4) Remove coolant bottle nuts/bolts. Position bot-
tle forward a few inches.
(5) Disconnect servo cable at throttle body. Refer to
servo Cable Removal/Installation.
(6) Remove servo bracket mounting nuts (Fig. 5).
(7) Remove 2 mounting nuts holding servo cable
sleeve to bracket (Fig. 6).
(8) Pull speed control cable sleeve and servo away
from servo mounting bracket to expose cable retain-
ing clip (Fig. 6) and remove clip. Note: The servo
Fig. 4 SPEED CONTROL CABLE AT BRACKET
1 - THROTTLE CABLE BRACKET
2 - PLASTIC CABLE MOUNT
3 - SPEED CONTROL CABLE
8P - 4 SPEED CONTROLKJ
CABLE (Continued)

mounting bracket displayed in (Fig. 6) is a typical
bracket and may/may not be applicable to this model
vehicle.
(9) Remove servo from mounting bracket. While
removing, note orientation of servo to bracket.INSTALLATION
(1) Position servo to mounting bracket.
(2) Align hole in cable connector with hole in servo
pin. Install cable-to-servo retaining clip.
(3) Insert servo mounting studs through holes in
servo mounting bracket.
(4) Install servo-to-mounting bracket nuts and
tighten. Refer to torque specifications.
(5) Install servo mounting bracket-to-body nuts
and tighten. Refer to torque specifications.
(6) Connect vacuum line at servo.
(7) Connect electrical connector at servo.
(8) Connect servo cable to throttle body. Refer to
servo Cable Removal/Installation.
(9) Install coolant bottle.
(10) Connect negative battery cable to battery.
(11) Before starting engine, operate accelerator
pedal to check for any binding.
SWITCH
DESCRIPTION
There are two separate switch pods that operate
the speed control system. The steering-wheel-
mounted switches use multiplexed circuits to provide
inputs to the PCM for ON, OFF, RESUME, ACCEL-
ERATE, SET, DECEL and CANCEL modes. Refer to
the owner's manual for more information on speed
control switch functions and setting procedures.
The individual switches cannot be repaired. If one
switch fails, the entire switch module must be
replaced.
OPERATION
When speed control is selected by depressing the
ON, OFF switch, the PCM allows a set speed to be
stored in its RAM for speed control. To store a set
speed, depress the SET switch while the vehicle is
moving at a speed between approximately 35 and 85
mph. In order for the speed control to engage, the
brakes cannot be applied, nor can the gear selector
be indicating the transmission is in Park or Neutral.
The speed control can be disengaged manually by:
²Stepping on the brake pedal
²Depressing the OFF switch
²Depressing the CANCEL switch.
The speed control can be disengaged also by any of
the following conditions:
²An indication of Park or Neutral
²The VSS signal increases at a rate of 10 mph
per second (indicates that the co-efficient of friction
between the road surface and tires is extremely low)
²Depressing the clutch pedal.
²Excessive engine rpm (indicates that the trans-
mission may be in a low gear)
Fig. 5 SPEED CONTROL SERVO
1-9T9FITTING
2 - VACUUM LINE
3 - SERVO BRACKET MOUNTING NUTS
4 - SERVO MOUNTING BRACKET
5 - SERVO
6 - SERVO ELECTRICAL CONNECTOR
Fig. 6 SERVO CABLE CLIP REMOVE/INSTALL
TYPICAL
1 - SERVO MOUNTING NUTS (2)
2 - SERVO
3 - CABLE RETAINING CLIP
4 - SERVO CABLE AND SLEEVE
KJSPEED CONTROL 8P - 5
SERVO (Continued)

²The VSS signal decreases at a rate of 10 mph
per second (indicates that the vehicle may have
decelerated at an extremely high rate)
²If the actual speed is not within 20 mph of the
set speed
The previous disengagement conditions are pro-
grammed for added safety.
Once the speed control has been disengaged,
depressing the ACCEL switch restores the vehicle to
the target speed that was stored in the PCM's RAM.
NOTE: Depressing the OFF switch will erase the set
speed stored in the PCM's RAM.
If, while the speed control is engaged, the driver
wishes to increase vehicle speed, the PCM is pro-
grammed for an acceleration feature. With the
ACCEL switch held closed, the vehicle accelerates
slowly to the desired speed. The new target speed is
stored in the PCM's RAM when the ACCEL switch is
released. The PCM also has a9tap-up9feature in
which vehicle speed increases at a rate of approxi-
mately 2 mph for each momentary switch activation
of the ACCEL switch.
The PCM also provides a means to decelerate with-
out disengaging speed control. To decelerate from an
existing recorded target speed, depress and hold the
COAST switch until the desired speed is reached.
Then release the switch. The ON, OFF switch oper-
ates two components: the PCM's ON, OFF input, and
the battery voltage to the brake switch, which powers
the speed control servo.
Multiplexing
The PCM sends out 5 volts through a fixed resistor
and monitors the voltage change between the fixed
resistor and the switches. If none of the switches are
depressed, the PCM will measure 5 volts at the sen-
sor point (open circuit). If a switch with no resistor is
closed, the PCM will measure 0 volts (grounded cir-
cuit). Now, if a resistor is added to a switch, then the
PCM will measure some voltage proportional to the
size of the resistor. By adding a different resistor to
each switch, the PCM will see a different voltage
depending on which switch is pushed.
Another resistor has been added to the 'at rest cir-
cuit' causing the PCM to never see 5 volts. This was
done for diagnostic purposes. If the switch circuit
should open (bad connection), then the PCM will see
the 5 volts and know the circuit is bad. The PCM will
then set an open circuit fault.
REMOVAL
WARNING: BEFORE ATTEMPTING TO DIAGNOSE,
REMOVE OR INSTALL ANY AIRBAG SYSTEM OR
RELATED STEERING WHEEL AND STEERING COL-
UMN COMPONENTS YOU MUST FIRST DISCON-
NECT AND ISOLATE THE NEGATIVE (GROUND)
BATTERY CABLE. WAIT 2 MINUTES FOR SYSTEM
CAPACITOR TO DISCHARGE BEFORE FURTHER
SYSTEM SERVICE. FAILURE TO DO SO COULD
RESULT IN ACCIDENTAL DEPLOYMENT AND POS-
SIBLE PERSONAL INJURY.
(1) Disconnect and isolate negative battery cable
from battery.
(2) Remove airbag module. Refer to Restraint Sys-
tems.
(3) Unplug electrical connector (Fig. 7).
(4) Remove speed control switch mounting screw
(Fig. 7) and remove switch from steering wheel.
INSTALLATION
(1) Position switch to steering wheel.
(2) Install switch mounting screw and tighten.
Refer to torque specifications.
(3) Plug electrical connector into switch.
(4) Install airbag module. Refer to Restraint Sys-
tems.
(5) Connect negative battery cable to battery.
Fig. 7 SPEED CONTROL SWITCH
1 - SWITCH
2 - SCREW
3 - ELECTRICAL CONNECTOR
8P - 6 SPEED CONTROLKJ
SWITCH (Continued)