2002 JEEP LIBERTY Low power

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)

(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)

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)

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)

²Combination Flasher- An electronic combina-
tion flasher is integral to the hazard switch located
in the center of the instrument panel above the
radio. (Refer to 8 - ELECTRICAL/LAMPS/LIGHT-
ING - EXTERIOR/COMBINATION FLASHER -
DESCRIPTION).
²Door Ajar Switch- A door ajar switch is inte-
gral to the latch of each door in the vehicle. (Refer to
8 - ELECTRICAL/LAMPS/LIGHTING - INTERIOR/
DOOR AJAR SWITCH - DESCRIPTION).
²Door Cylinder Lock Switch- For North
American vehicles only, a door cylinder lock switch is
located on the back of the lock cylinder of each front
door. (Refer to 8 - ELECTRICAL/VEHICLE THEFT
SECURITY/DOOR CYLINDER LOCK SWITCH -
DESCRIPTION).
²Flip-Up Glass Ajar Switch- A flip-up glass
ajar switch is integral to the rear flip-up glass latch,
located on the top of the tailgate near the center.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
INTERIOR/FLIP-UP GLASS AJAR SWITCH -
DESCRIPTION).
²Hood Ajar Switch- A hood ajar switch is
located beneath the hood panel on the right inner
fender side shield of vehicles built for sale in certain
markets where it is required equipment. (Refer to 8 -
ELECTRICAL/VEHICLE THEFT SECURITY/HOOD
AJAR SWITCH - DESCRIPTION).
²Horn Relay- A horn relay is located on the
Junction Block (JB) under the driver side outboard
end of the instrument panel. (Refer to 8 - ELECTRI-
CAL/HORN/HORN RELAY - DESCRIPTION).
²Intrusion Transceiver Module- An Intrusion
Transceiver Module (ITM) is located near the center
of the headliner in the passenger compartment of
vehicles built for sale in certain markets where it is
required equipment. (Refer to 8 - ELECTRICAL/VE-
HICLE THEFT SECURITY/UK SECURITY SYSTEM
MODULE - DESCRIPTION).
²Security Indicator- A security indicator is
located in the ElectroMechanical Instrument Cluster
(EMIC) on the instrument panel in front of the driver
side front seat. (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER/SECURITY INDICATOR -
DESCRIPTION).
²Siren- An alarm siren is located on the front
extension of the right front wheel house panel in the
engine compartment of vehicles built for sale in cer-
tain markets where it is required equipment. (Refer
to 8 - ELECTRICAL/VEHICLE THEFT SECURITY/
SIREN - DESCRIPTION).
²Tailgate Ajar Switch- A tailgate ajar switch is
integral to the latch for the tailgate in the vehicle.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
INTERIOR/TAILGATE AJAR SWITCH - DESCRIP-
TION).SENTRY KEY IMMOBILIZER SYSTEM The Sen-
try Key Immobilizer System (SKIS) is available as a
factory-installed option on this model. Vehicles
equipped with the Vehicle Theft Alarm (VTA) are also
equipped with SKIS. The SKIS provides passive vehi-
cle protection by preventing the engine from operat-
ing unless a valid electronically encoded key is
detected in the ignition lock cylinder. The SKIS
includes the following major components, which are
described in further detail elsewhere in this service
information:
²Powertrain Control Module- The Powertrain
Control Module (PCM) is located on the left inner
fender shield in the engine compartment near the
dash panel. (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/POWERTRAIN
CONTROL MODULE - DESCRIPTION).
²Sentry Key Immobilizer Module- The Sentry
Key Immobilizer Module (SKIM) is located beneath
the steering column shrouds on the right side of the
steering column near the ignition lock cylinder hous-
ing. (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/SENTRY KEY IMMOBILIZER
MODULE - DESCRIPTION).
²Sentry Key Transponder- The Sentry Key
transponder is molded into the head of the ignition
key, and concealed by a gray molded rubber cap.
(Refer to 8 - ELECTRICAL/VEHICLE THEFT SECU-
RITY/TRANSPONDER KEY - DESCRIPTION).
²SKIS Indicator- The SKIS indicator is located
in the ElectroMechanical Instrument Cluster (EMIC)
on the instrument panel in front of the driver side
front seat. (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER/SPEED CONTROL INDICATOR -
DESCRIPTION).
OPERATION
The Vehicle Theft Security System (VTSS) is
divided into two basic subsystems: Vehicle Theft
Alarm (VTA) and Sentry Key Immobilizer System
(SKIS). Following are paragraphs that briefly
describe the operation of each of these two sub-
systems.
VEHICLE THEFT ALARM The Body Control Mod-
ule (BCM) is used on this model to control and inte-
grate many of the electronic functions and features
included in the Vehicle Theft Alarm (VTA). The BCM
receives hard wired inputs indicating the status of
the door ajar switches, the door cylinder lock
switches, the ignition switch, the tailgate ajar switch,
the tailgate cylinder lock switch, the flip-up glass
ajar switch, the power lock switches and, in vehicles
built for certain markets where it is required, the
hood ajar switch. The programming in the BCM
allows it to process the information from all of these
inputs and send control outputs to energize or de-en-
KJVEHICLE THEFT SECURITY 8Q - 3
VEHICLE THEFT SECURITY (Continued)

ergize the combination flasher, the horn relay (except
vehicles with the Rest-Of-World or ROW premium
version of the VTA), and the security indicator. In
addition, in vehicles built for certain markets where
the ROW premium version of the VTA is required,
the BCM also exchanges electronic messages with
the Intrusion Transceiver Module (ITM) over the Pro-
grammable Communications Interface (PCI) data bus
network to provide the features found in this version
of the VTA.
The hard wired circuits and components of the
VTA may be diagnosed and tested using conventional
diagnostic tools and procedures. However, conven-
tional diagnostic methods may not prove conclusive
in the diagnosis of the Body Control Module (BCM),
the ElectroMechanical Instrument Cluster (EMIC),
the Intrusion Transceiver Module (ITM), or the Pro-
grammable Communications Interface (PCI) data bus
network. The most reliable, efficient, and accurate
means to diagnose the BCM, the EMIC, the ITM,
and the PCI data bus network inputs and outputs
related to the VTA requires the use of a DRBIIIt
scan tool. Refer to the appropriate diagnostic infor-
mation. Following are paragraphs that briefly
describe the operation of each of the VTA features.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the VTA.
²ENABLING- The BCM must have the VTA
function electronically enabled in order for the VTA
to perform as designed. The logic in the BCM keeps
its VTA function dormant until it is enabled using a
DRBIIItscan tool. The VTA function of the BCM is
enabled on vehicles equipped with the VTA option at
the factory, but a service replacement BCM must be
VTA-enabled by the dealer using a DRBIIItscan
tool. Refer to the appropriate diagnostic information.
²PRE-ARMING- The VTA has a pre-arming
sequence. Pre-arming occurs when a door, the tail-
gate, or the flip-up glass is open when the vehicle is
locked using a power lock switch, or when the ªLockº
button on the Remote Keyless Entry (RKE) transmit-
ter is depressed. The power lock switch will not ini-
tiate the pre-arming sequence if the key is in the
ignition switch. When the VTA is pre-armed, the
arming sequence is delayed until all of the doors, the
tailgate, and the flip-up glass are closed.
²ARMING- Passive arming of the VTA occurs
when the vehicle is exited with the key removed from
the ignition switch and the doors are locked while
they are open using the power lock switch (see Pre-
Arming). Active arming of the VTA occurs when the
ªLockº button on the Remote Keyless Entry (RKE)
transmitter is depressed to lock the vehicle after all
of the doors, the tailgate, and the flip-up glass are
closed. The VTA will not arm if the doors are lockedusing the key in a lock cylinder or using a mechani-
cal lock button. Once the VTA begins the passive or
active arming sequence, the security indicator in the
instrument cluster will flash rapidly for about six-
teen seconds. This indicates that the VTA arming
sequence is in progress. If the ignition switch is
turned to the On position, if a door is unlocked with
the power lock switch or the RKE transmitter, or if
the tailgate is unlocked by any means during the six-
teen second arming sequence, the security indicator
will stop flashing and the VTA arming sequence will
abort. On vehicles equipped with the hood ajar
switch, the VTA arming sequence will occur regard-
less of whether the hood is open or closed, but the
underhood area will not be protected unless the hood
is closed when the VTA arming sequence begins.
Also, if the status of the hood ajar switch changes
from open (hood closed) to closed (hood open) during
the sixteen second arming sequence, the security
indicator will stop flashing and the VTA arming
sequence will abort. Once the sixteen second arming
sequence is successfully completed, the security indi-
cator will flash at a slower rate, indicating that the
VTA is armed.
²DISARMING- For vehicles built for the North
American market, disarming of the VTA occurs when
the vehicle is unlocked using the key to unlock a door
or the tailgate. Disarming of the VTA for any market
also occurs when the vehicle is unlocked by depress-
ing the ªUnlockº button of the Remote Keyless Entry
(RKE) transmitter, or by turning the ignition switch
to the On position using a valid Sentry Key Immobi-
lizer System (SKIS) key. Once the alarm has been
activated, any of these disarming methods will also
deactivate the alarm.
²POWER-UP MODE- When the armed VTA
senses that the battery has been disconnected and
reconnected, it enters its power-up mode. In the pow-
er-up mode the alarm system returns to the mode
that was last selected prior to the battery failure or
disconnect. If the VTA was armed prior to the battery
disconnect or failure, the technician or vehicle opera-
tor will have to actively or passively disarm the sys-
tem after the battery is reconnected. The power-up
mode will also apply if the battery goes dead while
the system is armed, and battery jump-starting is
then attempted. The VTA will remain armed until
the technician or vehicle operator has actively or pas-
sively disarmed the system. If the VTA is in the dis-
armed mode prior to a battery disconnect or failure,
it will remain disarmed after the battery is recon-
nected or replaced, or if jump-starting is attempted.
²ALARM- The VTA alarm output varies by the
version of the VTA with which the vehicle is
equipped. In all cases, the alarm provides both visual
and audible outputs; however, the time intervals of
8Q - 4 VEHICLE THEFT SECURITYKJ
VEHICLE THEFT SECURITY (Continued)

continuity. If OK, go to Step 6. If not OK, repair the
open ground circuit(s) to ground (G202) as required.
(6) Reconnect the battery negative cable. Check for
battery voltage at the fused B(+) circuit cavity of the
instrument panel wire harness connector for the
SKIM. If OK, go to Step 7. If not OK, repair the open
fused B(+) circuit between the SKIM and the JB as
required.
(7) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run-start) circuit cavity of the instrument
panel wire harness connector for the SKIM. If OK,
use a DRBIIItscan tool to complete the diagnosis of
the SKIS. Refer to the appropriate diagnostic infor-
mation. If not OK, repair the open fused ignition
switch output (run-start) circuit between the SKIM
and the JB as required.
SKIS INDICATOR FLASHES UPON IGNITION ªONº OR
LIGHTS SOLID FOLLOWING BULB TEST
A SKIS indicator that flashes following the ignition
switch being turned to the On position indicates that
an invalid key has been detected, or that a key-re-
lated fault has been set. A SKIS indicator that lights
solid following a successful bulb test indicates that
the SKIM has detected a system malfunction or that
the SKIS is inoperative. In either case, fault informa-
tion will be stored in the SKIM memory. For retrieval
of this fault information and further diagnosis of the
SKIS, the PCI data bus, the SKIM electronic mes-
sage outputs to the instrument cluster that control
the SKIS indicator and chime, or the electronic mes-
sage inputs and outputs between the SKIM and the
Powertrain Control Module (PCM) that control
engine operation, a DRBIIItscan tool is required.
Refer to the appropriate diagnostic information. Fol-
lowing are preliminary troubleshooting guidelines to
be followed during diagnosis using a DRBIIItscan
tool:
(1) Using the DRBIIItscan tool, read and record
the faults as they exist in the SKIM when you first
begin your diagnosis of the vehicle. It is important to
document these faults because the SKIM does not
differentiate between historical faults (those that
have occurred in the past) and active faults (those
that are currently present). If this problem turns out
to be an intermittent condition, this information may
become invaluable to your diagnosis.
(2) Using the DRBIIItscan tool, erase all of the
faults from the SKIM.
(3) Cycle the ignition switch to the Off position,
then back to the On position.
(4) Using the DRBIIItscan tool, read any faults
that are now present in the SKIM. These are the
active faults.(5) Using this active fault information, refer to the
proper procedure in the appropriate diagnostic infor-
mation for the specific additional diagnostic steps.
STANDARD PROCEDURE
STANDARD PROCEDURE - SKIS
INITIALIZATION
The Sentry Key Immobilizer System (SKIS) must
be initialized following a Sentry Key Immobilizer
Module (SKIM) replacement. SKIS initialization
requires the use of a DRBIIItscan tool. Initialization
will also require that you have access to the unique
four-digit PIN code that was assigned to the original
SKIM. The PIN codemustbe used to enter the
Secured Access Mode in the SKIM. This PIN number
may be obtained from the vehicle owner, from the
original vehicle invoice, or from the DaimlerChrysler
Customer Center. (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES - STANDARD PRO-
CEDURE - PCM/SKIM PROGRAMMING).
NOTE: If a Powertrain Control Module (PCM) is
replaced on a vehicle equipped with the Sentry Key
Immobilizer System (SKIS), the unique Secret Key
data must be transferred from the Sentry Key
Immobilizer Module (SKIM) to the new PCM using
the PCM replacement procedure. This procedure
also requires the use of a DRBIIITscan tool and the
unique four-digit PIN code to enter the Secured
Access Mode in the SKIM. Refer to the appropriate
diagnostic information for the proper PCM replace-
ment procedures.
STANDARD PROCEDURE - SENTRY KEY
TRANSPONDER PROGRAMMING
All Sentry Keys included with the vehicle are pre-
programmed to work with the Sentry Key Immobi-
lizer System (SKIS) when it is shipped from the
factory. The Sentry Key Immobilizer Module (SKIM)
can be programmed to recognize up to a total of eight
Sentry Keys. When programming a blank Sentry Key
transponder, the key must first be cut to match the
ignition switch lock cylinder in the vehicle for which
it will be used. Once the additional or new key has
been cut, the SKIM must be programmed to recog-
nize it as a valid key. There are two possible methods
to program the SKIM to recognize a new or addi-
tional valid key, the Secured Access Method and the
Customer Learn Method. Following are the details of
these two programming methods.
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VEHICLE THEFT SECURITY (Continued)