2002 JEEP LIBERTY immobilizer

VEHICLE THEFT SECURITY
TABLE OF CONTENTS
page page
VEHICLE THEFT SECURITY
DESCRIPTION..........................1
OPERATION............................3
DIAGNOSIS AND TESTING - VEHICLE THEFT
SECURITY SYSTEM....................6
STANDARD PROCEDURE
STANDARD PROCEDURE - SKIS
INITIALIZATION........................8
STANDARD PROCEDURE - SENTRY KEY
TRANSPONDER PROGRAMMING..........8
DOOR CYLINDER LOCK SWITCH
DESCRIPTION..........................9
OPERATION...........................10
DIAGNOSIS AND TESTING - DOOR
CYLINDER LOCK SWITCH..............10
REMOVAL.............................10
INSTALLATION.........................10
HOOD AJAR SWITCH
DESCRIPTION.........................11
OPERATION...........................12
DIAGNOSIS AND TESTING - HOOD AJAR
SWITCH............................12REMOVAL.............................12
INSTALLATION.........................12
HOOD AJAR SWITCH BRACKET
REMOVAL.............................13
INSTALLATION.........................13
HOOD AJAR SWITCH STRIKER
REMOVAL.............................13
INSTALLATION.........................14
INTRUSION TRANSCEIVER MODULE
DESCRIPTION.........................14
OPERATION...........................15
REMOVAL.............................15
INSTALLATION.........................16
SIREN
DESCRIPTION.........................16
OPERATION...........................17
REMOVAL.............................17
INSTALLATION.........................17
TRANSPONDER KEY
DESCRIPTION.........................18
OPERATION...........................18
VEHICLE THEFT SECURITY
DESCRIPTION
The Vehicle Theft Security System (VTSS) is an
available factory-installed option on this model (Fig.
1). The VTSS is comprised of two primary sub-
systems: Vehicle Theft Alarm (VTA) and Sentry Key
Immobilizer System (SKIS). The VTA is an active
system that provides visual and audible responses as
deterrents to and warnings of unauthorized vehicle
tampering. The SKIS is a passive system that effec-
tively immobilizes the vehicle against unauthorized
operation. Following are paragraphs which describe
the various components that are included in each of
these subsystems of the VTSS.
Hard wired circuitry connects many of the VTSS
components to each other through the electrical sys-
tem of the vehicle. These hard wired circuits are
integral to several wire harnesses, which are routed
throughout the vehicle and retained by many differ-
ent methods. These circuits may be connected to each
other, to the vehicle electrical system and to the
VTSS components through the use of a combination
of soldered splices, splice block connectors, and many
different types of wire harness terminal connectorsand insulators. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
further details on wire harness routing and reten-
tion, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
VEHICLE THEFT ALARM The VTA is available in
two different configurations for this vehicle: One con-
figuration is designed for vehicles manufactured for
sale in North America; while, the other configuration
is designed for vehicles manufactured for sale in
markets outside of North America, also referred to as
Rest-Of-World or ROW. In addition, the VTA for
ROW is available in two versions: base and premium.
All vehicles equipped with VTA are also equipped
with the Remote Keyless Entry (RKE) system and
the Sentry Key Immobilizer System (SKIS), regard-
less of their market destination. The North American
and ROW base version of the VTA provides perimeter
vehicle protection by monitoring the vehicle doors,
the tailgate, the rear flip-up glass and, for vehicles
built for certain markets where it is required equip-
ment, the hood. If unauthorized vehicle use or tam-
pering is detected, these systems respond by pulsing
the horn and flashing certain exterior lamps. The
ROW premium version of the VTA is only available
KJVEHICLE THEFT SECURITY 8Q - 1

in vehicles manufactured for sale in certain markets
where it is required equipment. The ROW premium
version of the VTA provides the same perimeter pro-
tection features as the base version, but adds interior
vehicle intrusion protection. The ROW premium VTA
also replaces the pulsing horn feature of the base
version with an alarm siren as the audible deterrent,
while retaining the flashing exterior lamps visual
deterrent.The VTA includes the following major components,
which are described in further detail elsewhere in
this service information:
²Body Control Module- The Body Control
Module (BCM) is located on the Junction Block (JB)
under the driver side outboard end of the instrument
panel. (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/BODY CONTROL MODULE
- DESCRIPTION).
Fig. 1 Vehicle Theft Security System
1 - SIREN MODULE
2 - BODY CONTROL MODULE
3 - SENTRY KEY IMMOBILIZER MODULE4 - DOOR CYLINDER LOCK SWITCH (2)
5 - INTRUSION TRANSCEIVER MODULE
8Q - 2 VEHICLE THEFT SECURITYKJ
VEHICLE THEFT SECURITY (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)

these outputs vary by the requirements of the mar-
ket for which the vehicle is manufactured. In all
cases, the visual output will be a flashing on and off
of the exterior lamps. For vehicles equipped with the
North American or the ROW base version of the
VTA, the audible output will be a pulsing of the horn.
For vehicles with the ROW premium version of the
VTA, the audible output will be a cycling of the
alarm siren. See the owner's manual in the vehicle
glove box for details of the alarm output require-
ments of the specific market for which the vehicle
was manufactured. The inputs that will trigger the
alarm include the door ajar switches, the tailgate
ajar switch, the flip-up glass ajar switch, and in vehi-
cles built for certain markets where they are
required, the hood ajar switch and the Intrusion
Transceiver Module (ITM).
²TAMPER ALERT- The VTA tamper alert fea-
ture will pulse the horn (or the alarm siren for the
ROW premium version of the VTA) three times upon
VTA disarming, if the alarm was triggered and has
since timed-out. This feature alerts the vehicle oper-
ator that the VTA alarm was activated while the
vehicle was unattended.
²INTRUSION ALARM- The intrusion alarm is
an exclusive feature of the ROW premium version of
the VTA, which is only available in certain markets
where it is required. When the VTA is armed, a
motion sensor in the Intrusion Transceiver Module
(ITM) monitors the interior of the vehicle for move-
ment. If motion is detected, the ITM sends an elec-
tronic message to the BCM over the PCI data bus to
invoke the visual alarm feature, and sends an elec-
tronic message to the alarm siren in the engine com-
partment over a dedicated serial bus to invoke the
audible alarm feature. The motion detect feature of
the ITM can be disabled by depressing the ªLockº
button on the RKE transmitter three times within
fifteen seconds during VTA arming, while the secu-
rity indicator is still flashing rapidly. The VTA pro-
vides a single short siren ªchirpº as an audible
confirmation that the motion detect disable request
has been received. The ITM must be electronically
enabled in order for the intrusion alarm to perform
as designed. The logic in the ITM keeps its intrusion
alarm function dormant until it is enabled using a
DRBIIItscan tool. The intrusion alarm function of
the ITM is enabled on vehicles equipped with thisoption at the factory, but a service replacement ITM
must be configured and enabled by the dealer using a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.
SENTRY KEY IMMOBILIZER SYSTEM The Sen-
try Key Immobilizer System (SKIS) is designed to
provide passive protection against unauthorized vehi-
cle use by disabling the engine after about two sec-
onds of running, whenever any method other than a
valid Sentry Key is used to start the vehicle. The
SKIS is considered a passive protection system
because it is always active when the ignition system
is energized and does not require any customer inter-
vention. The SKIS uses Radio Frequency (RF) com-
munication to obtain confirmation that the key in the
ignition switch is a valid key for operating the vehi-
cle. The microprocessor-based SKIS hardware and
software also use electronic messages to communi-
cate with other electronic modules in the vehicle over
the Programmable Communications Interface (PCI)
data bus. (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/COMMUNICATION - OPER-
ATION).
Pre-programmed Sentry Key transponders are pro-
vided with the vehicle from the factory. Each Sentry
Key Immobilizer Module (SKIM) will recognize a
maximum of eight Sentry Keys. If the customer
would like additional keys other than those provided
with the vehicle, they may be purchased from any
authorized dealer. These additional keys must be pro-
grammed to the SKIM in the vehicle in order for the
system to recognize them as valid keys. This can be
done by the dealer using a DRBIIItscan tool or, if
Customer Learn programming is an available SKIS
feature in the market where the vehicle was pur-
chased, the customer can program the additional
keys, as long as at least two valid Sentry Keys are
already available. (Refer to 8 - ELECTRICAL/VEHI-
CLE THEFT SECURITY - STANDARD PROCE-
DURE - TRANSPONDER PROGRAMMING).
The SKIS performs a self-test each time the igni-
tion switch is turned to the On position, and will
store fault information in the form of Diagnostic
Trouble Codes (DTC's) if a system malfunction is
detected. The SKIS can be diagnosed, and any stored
DTC's can be retrieved using a DRBIIItscan tool.
Refer to the appropriate diagnostic information.
KJVEHICLE THEFT SECURITY 8Q - 5
VEHICLE THEFT SECURITY (Continued)

DIAGNOSIS AND TESTING - VEHICLE THEFT
SECURITY SYSTEM
The Vehicle Theft Security System (VTSS) is
divided into two basic subsystems: Vehicle Theft
Alarm (VTA) and Sentry Key Immobilizer System
(SKIS). Following are the recommended procedures
for diagnosis and testing of each of these two sub-
systems.
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.
VEHICLE THEFT ALARM
Models equipped with the Rest-Of-World (ROW)
premium version of the Vehicle Theft Alarm (VTA)
provide some preliminary diagnostic feedback by illu-minating the security indicator located in the Elec-
troMechanical Instrument Cluster (EMIC). If the
security indicator illuminates with the ignition
switch in the On position, it indicates that there is a
communication problem between the Intrusion
Transceiver Module (ITM) and the Body Control
Module (BCM), or between the ITM and the siren
module. The BCM will also turn on the security indi-
cator if it receives a message from the ITM indicating
that the ITM has stored a Diagnostic Trouble Code
(DTC) for a siren module fault.
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.
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 har-
ness connectors, splices and grounds.
8Q - 6 VEHICLE THEFT SECURITYKJ
VEHICLE THEFT SECURITY (Continued)

SENTRY KEY IMMOBILIZER SYSTEM
SENTRY KEY IMMOBILIZER SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
SKIS INDICATOR FAILS TO
LIGHT DURING BULB TEST1. SKIS indicator faulty. 1. Test and replace the instrument cluster as
required.
2. Fuse faulty. 2. Test and replace the SKIM fused B(+) and
fused ignition switch output (run-start) fuses in the
Junction Block (JB) as required.
3. Ground circuit faulty. 3. Test and repair the SKIM ground circuit as
required.
4. Fused B(+) circuit faulty. 4. Test and repair the SKIM fused B(+) circuit as
required.
5. Fused ignition switch
output circuit faulty.5. Test and repair the SKIM fused ignition switch
output (run-start) circuit as required.
SKIS INDICATOR FLASHES
WHEN IGNITION SWITCH IS
TURNED TO9ON9
POSITION1. Invalid key in ignition
switch lock cylinder.1. Replace the key with a known valid key.
2. Key-related fault. 2. Use a DRBIIITscan tool to diagnose the
key-related fault. Refer to the appropriate
diagnostic information.
SKIS INDICATOR LIGHTS
SOLID FOLLOWING BULB
TEST1. SKIS system malfunction/
fault detected.1. Use a DRBIIITscan tool to diagnose the SKIS.
Refer to the appropriate diagnostic information.
2. SKIS system inoperative. 2. Use a DRBIIITscan tool to diagnose the SKIS.
Refer to the appropriate diagnostic information.
SKIS INDICATOR FAILS TO LIGHT DURING BULB TEST
If the Sentry Key Immobilizer System (SKIS) indi-
cator in the instrument cluster fails to illuminate for
about three seconds after the ignition switch is
turned to the On position (bulb test), perform the
instrument cluster actuator test. (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING). If the SKIS indicator still fails to
light during the bulb test, a wiring problem resulting
in the loss of battery current or ground to the Sentry
Key Immobilizer Module (SKIM) should be sus-
pected, and the following procedure should be used
for diagnosis. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
details of wire harness routing and retention, connec-
tor pin-out information and location views for the
various wire harness connectors, splices and grounds.
NOTE: The following tests may not prove conclu-
sive in the diagnosis of this system. The most reli-
able, efficient, and accurate means to diagnose the
Sentry Key Immobilizer System requires the use of
a DRBIIITscan tool. Refer to the appropriate diag-
nostic information.(1) Check the fused B(+) fuse (Fuse 33 - 10
ampere) in the Junction Block (JB). If OK, go to Step
2. If not OK, repair the shorted circuit or component
as required and replace the faulty fuse.
(2) Check for battery voltage at the fused B(+) fuse
(Fuse 33 - 10 ampere) in the JB. If OK, go to Step 3.
If not OK, repair the open B(+) circuit between the
JB and the battery as required.
(3) Check the fused ignition switch output (run-
start) fuse (Fuse 15 - 10 ampere) in the JB. If OK, go
to Step 4. If not OK, repair the shorted circuit or
component as required and replace the faulty fuse.
(4) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run-start) fuse (Fuse 15 - 10 ampere) in the
JB. If OK, go to Step 5. If not OK, repair the open
fused ignition switch output (run-start) circuit
between the JB and the ignition switch as required.
(5) Disconnect and isolate the battery negative
cable. Disconnect the instrument panel wire harness
connector for the Sentry Key Immobilizer Module
(SKIM) from the SKIM connector receptacle. Check
for continuity between each of the two ground circuit
cavities of the instrument panel wire harness connec-
tor for the SKIM and a good ground. There should be
KJVEHICLE THEFT SECURITY 8Q - 7
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.
8Q - 8 VEHICLE THEFT SECURITYKJ
VEHICLE THEFT SECURITY (Continued)

(2) Install and tighten the two screws that secure
the alarm siren module to the front extension of the
right front wheel house panel. Tighten the screws to
6 N´m (50 in. lbs.).
(3) Reconnect the headlamp and dash wire harness
connector for the alarm siren module to the module
connector receptacle.
(4) Reconnect the battery negative cable.
NOTE: If the alarm siren module has been replaced
with a new unit, the new unit MUST be configured
in the Intrusion Transceiver Module (ITM) before the
Vehicle Theft Security System can operate as
designed. The use of a DRBIIITscan tool is required
to configure the alarm siren module settings in the
ITM. Refer to the appropriate diagnostic informa-
tion.
TRANSPONDER KEY
DESCRIPTION
Each ignition key used in the Sentry Key Immobi-
lizer System (SKIS) has an integral transponder chip
(Fig. 15). Ignition keys with this feature can be
readily identified by a gray rubber cap molded onto
the head of the key, while conventional ignition keys
have a black molded rubber cap. The transponderchip is concealed beneath the molded rubber cap,
where it is molded within a plastic mount into the
head of the metal key. In addition to being cut to
match the mechanical coding of the ignition lock cyl-
inder, each new Sentry Key has a unique transpon-
der identification code permanently programmed into
it by the manufacturer. The Sentry Key transponder
cannot be adjusted or repaired. If faulty or damaged,
the entire key must be replaced.
OPERATION
When the ignition switch is turned to the On posi-
tion, the Sentry Key Immobilizer Module (SKIM)
communicates through its antenna with the Sentry
Key transponder using a Radio Frequency (RF) sig-
nal. The SKIM then listens for a RF response from
the transponder through the same antenna. The Sen-
try Key transponder chip is within the range of the
SKIM transceiver antenna ring when it is inserted
into the ignition lock cylinder. The SKIM determines
whether a valid key is present in the ignition lock
cylinder based upon the response from the transpon-
der. If a valid key is detected, that fact is communi-
cated by the SKIM to the Powertrain Control Module
(PCM) over the Programmable Communications
Interface (PCI) data bus, and the PCM allows the
engine to continue running. If the PCM receives an
invalid key message, or receives no message from the
SKIM over the PCI data bus, the engine will be dis-
abled after about two seconds of operation. The Elec-
troMechanical Instrument Cluster (EMIC) will also
respond to the invalid key message on the PCI data
bus by flashing the SKIS indicator on and off.
Fig. 14 Siren Remove/Install
1 - SCREW (2)
2 - WIRE HARNESS CONNECTOR
3 - SIREN
Fig. 15 Sentry Key Immobilizer Transponder
1 - MOLDED CAP
2 - TRANSPONDER CHIP
3 - MOLDED CAP REMOVED
4 - TRANSPONDER KEY
8Q - 18 VEHICLE THEFT SECURITYKJ
SIREN (Continued)