2002 JEEP LIBERTY remote control

REMOTE KEYLESS ENTRY
TRANSMITTER
DIAGNOSIS AND TESTING - REMOTE KEYLESS
ENTRY TRANSMITTER
The most reliable, efficient, and accurate means to
diagnose the remote keyless entry transmitter
requires the use of a DRBIIItscan tool and the
proper Diagnostic Procedures manual. The DRBIIIt
scan tool can provide confirmation that the PCI data
bus is functional, and that all of the electronic mod-
ules are sending and receiving the proper messages
on the PCI data bus.
STANDARD PROCEDURE
STANDARD PROCEDURE - RKE TRANSMITTER
BATTERIES
The Remote Keyless Entry (RKE) transmitter case
snaps open and shut for battery access. To replace
the RKE transmitter batteries:(1) Using a thin coin, gently pry at the notch in
the center seam of the RKE transmitter case halves
near the key ring until the two halves unsnap.
(2) Lift the back half of the transmitter case off of
the RKE transmitter.
(3) Remove the two batteries from the RKE trans-
mitter.
(4) Replace the two batteries with new Panasonic
2016, or equivalent. Be certain that the batteries are
installed with their polarity correctly oriented.
(5) Align the two RKE transmitter case halves
with each other, and squeeze them firmly and evenly
together until they snap back into place.
STANDARD PROCEDURE - RKE TRANSMITTER
CUSTOMER PREFERENCES
AUTOMATIC (ROLLING) LOCKS
The rolling locks feature can be toggled ON/OFF
by using the DRB IIItonly.
HORN CHIRP DISABLING / ENABLING
The horn chirp can be toggled using a DRB IIItor
by using the Remote Keyless Entry (RKE) transmit-
ter.
To DISABLE (cancel) the horn chirp feature, press
and hold the transmitter LOCK button for four to ten
seconds. While pressing the LOCK button in, press
the UNLOCK button. Release both buttons.
To ENABLE the horn chirp feature, repeat the
above procedure.
OPTICAL CHIRP (FLASH) DISABLING / ENABLING
The optical chirp can be toggled using a DRB IIIt
or by using the Remote Keyless Entry (RKE) trans-
mitter.
To DISABLE (cancel) the optical chirp feature,
press and hold the transmitter LOCK button for four
to ten seconds. While pressing the LOCK button in,
press the TAILGATE RELEASE button. Release both
buttons.
To ENABLE the optical chirp feature, repeat the
above procedure.
TAIL GATE RELEASE DELAY
Press the UNLOCK button for four to ten seconds.
While pressing the UNLOCK button, press the TAIL
GATE RELEASE button. Release both buttons.
This will toggle between PRESS AND HOLD and
PRESS (no delay).
UNLOCK SEQUENCE
The unlock sequence can be toggled using a DRB
IIItor by using the Remote Keyless Entry (RKE)
transmitter.
Fig. 5 RKE Module Remove/Install
1 - SCREW (4)
2 - RKE MODULE
3 - BODY CONTROL MODULE
4 - JUNCTION BLOCK
8N - 8 POWER LOCKSKJ
REMOTE KEYLESS ENTRY MODULE (Continued)

Press and hold the transmitter UNLOCK button
for four to ten seconds. While pressing the UNLOCK
button in, press the LOCK button. Release both but-
tons.
This will toggle between Driver door first and
Unlock all doors function.
STANDARD PROCEDURE - RKE TRANSMITTER
PROGRAMING
New Remote Keyless Entry (RKE) transmitters can
be programed using the DRBIIItscan tool and the
proper Diagnostic Procedures manual. The DRBIIIt
scan tool can provide confirmation that the PCI data
bus is functional, and that all of the electronic mod-
ules are sending and receiving the proper messages
on the PCI data bus.
The following procedure can be used as long as one
functioning transmitter is available:
(1) Using the original transmitter, press the
UNLOCK button for 4 to 10 seconds.
(2) Without releasing the UNLOCK button, press
the PANIC button (within the 4 to 10 second inter-
val).
(3) Release both buttons.
(4) Press LOCK and UNLOCK simultaneously on
the original transmitter.
(5) Release both buttons.
(6) Press any button on the ORIGINAL transmit-
ter. A chime tone from the instrument cluster will
confirm the programming of the ORIGINAL trans-
mitter.
(7) On NEW transmitter, press LOCK and
UNLOCK simultaneously.
(8) Release both buttons.
(9) Press any button on the NEW transmitter. A
chime tone from the instrument cluster will confirm
the programming of the NEW transmitter.
(10) Up to four transmitters can be programed for
one vehicle.
SPECIFICATIONS - REMOTE KEYLESS ENTRY
TRANSMITTER
RANGE
Normal operation range is up to a distance of 3 to
7 meters (10 to 23 ft.) of the vehicle. Range may be
better or worse depending on the environment
around the vehicle.
TAILGATE CYLINDER LOCK
SWITCH
DESCRIPTION
The tailgate cylinder lock switch is integral to the
key lock cylinder inside the tailgate. The tailgate cyl-
inder lock switch is a normally-open momentary
switch that is hard wired directly to the Body Con-
trol Module (BCM), and closes a path to ground
through an internal resistor when the lock cylinder is
rotated to the unlock or lock position.
The tailgate cylinder lock switch cannot be
adjusted or repaired.
OPERATION
The tailgate cylinder lock switch is actuated when
the key is inserted in the lock cylinder and turned to
the unlock or lock position. The tailgate cylinder lock
switch closes a path to ground through an internal
resistor for the Body Control Module (BCM) when
the tailgate key lock cylinder is in the lock or unlock
position, and opens the ground path when the lock
cylinder is in the neutral position. The BCM reads
the switch status, then sends the proper switch sta-
tus messages to other electronic modules over the
Programmable Communications Interface (PCI) data
bus network. The tailgate cylinder lock switch unlock
status message is used by the BCM as an input for
Vehicle Theft Security System (VTSS) operation and
to tell the BCM to lock or unlock the tailgate. There
is no mechanical linkage between the tailgate key
cylinder and the latches.
DIAGNOSIS AND TESTING - TAILGATE
CYLINDER LOCK SWITCH
(1) Disconnect and isolate the battery negative
cable.
(2) Remove tailgate trim panel (Refer to 23 -
BODY/DECKLID/HATCH/LIFTGATE/TAILGATE/
TRIM PANEL - REMOVAL).
(3) Disconnect tailgate cylinder lock switch har-
ness connector.
(4) Using a ohmmeter, test for resistances as
shown in the Tailgate Cylinder Lock Switch Table.
KJPOWER LOCKS 8N - 9
REMOTE KEYLESS ENTRY TRANSMITTER (Continued)

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

NOTE: The integral flange on the left side of the
ACM cover is secured to the floor panel transmis-
sion tunnel with a short piece of double-faced tape
as an assembly aid during the manufacturing pro-
cess, but this tape does not require replacement
following service removal.
(7) Reinstall the center console onto the top of the
floor panel transmission tunnel. (Refer to 23 - BODY/
INTERIOR/FLOOR CONSOLE - INSTALLATION).
(8) 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).
CHILD TETHER ANCHOR
DESCRIPTION
All vehicles are equipped with three, fixed-position,
child seat tether anchors (Fig. 9). Two anchors are
integral to the back of the right rear seat back panel,
and one is integral to the left rear seat back panel.
The child seat tether anchors cannot be adjusted or
repaired and, if faulty or damaged, they must be
replaced as a unit with the rear seat back panel.
OPERATION
See the owner's manual in the vehicle glove box for
more information on the proper use of the factory-in-
stalled child seat tether anchors.
CLOCKSPRING
DESCRIPTION
The clockspring assembly is secured with two inte-
gral plastic latches onto the upper steering column
housing near the top of the steering column behind
the steering wheel (Fig. 10). The clockspring consists
of a flat, round molded plastic case with a stubby tail
that hangs below the steering column and contains
two connector receptacles that face toward the
instrument panel (Fig. 11). Within the plastic hous-
ing is a spool-like molded plastic rotor with a large
exposed hub and several plastic rollers. The upper
surface of the rotor hub has a large center hole, a
release button, a clear plastic inspection window, two
short pigtail wires with connectors, and a connector
receptacle that faces toward the steering wheel. Two
versions of the clockspring are used on this model,
one is a seven circuit unit for vehicles not equipped
with optional remote radio switches on the steering
wheel and can be visually identified by the use of yel-
low heat-shrink tubing on the pigtail wires, while the
other is a nine circuit unit for vehicles with remote
radio switches and can be visually identified by the
use of black heat-shrink tubing on the pigtail wires.
A rubber bumper block is located on each side of
the tower formation that contains the connector
receptacle and pigtail wires on the upper surface of
the rotor hub. The lower surface of the rotor hub has
Fig. 9 Child Tether Anchors
1 - REAR SEAT BACK (LEFT)
2 - REAR SEAT BACK (RIGHT)
3 - CHILD TETHER ANCHOR (3)
Fig. 10 Clockspring
1 - PIGTAIL WIRE (2)
2 - UPPER CONNECTOR RECEPTACLE
3 - BUMPER (2)
4 - BRACKET (2)
5 - LABEL
6 - SHIELD
7 - CASE
8 - WINDOW
9 - ROTOR
KJRESTRAINTS 8O - 13
AIRBAG CONTROL MODULE (Continued)

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

FRONT IMPACT SENSOR
DESCRIPTION
Two front impact sensors are used on this model,
one each for the left and right sides of the vehicle
(Fig. 17). These sensors are mounted remotely from
the impact sensor that is internal to the Airbag Con-
trol Module (ACM). Each front sensor is secured with
two screws to the backs of the right and left vertical
members of the radiator support within the engine
compartment. The sensor housing has an integral
connector receptacle and two integral mounting
points each with a metal sleeve to provide crush pro-
tection.
The right and left front impact sensors are identi-
cal in construction and calibration with two excep-
tions:
²On models equipped with an optional 2.4L gaso-
line engine, the left front impact sensor includes a
shim that moves the sensor three millimeters toward
the rear of the vehicle on the left vertical member of
the radiator support for additional clearance that is
required for that application.
²On models equipped with an optional diesel
engine, the left front impact sensor includes a
stamped metal mounting bracket that rotates theconnector receptacle end of the sensor toward the
outboard side of the vehicle for additional clearance
that is required for that application.
A cavity in the center of the molded black plastic
impact sensor housing contains the electronic cir-
cuitry of the sensor which includes an electronic com-
munication chip and an electronic impact sensor.
Potting material fills the cavity to seal and protect
the internal electronic circuitry and components. The
front impact sensors are each connected to the vehi-
cle electrical system through a dedicated take out
and connector of the headlamp and dash wire har-
ness.
The impact sensors cannot be repaired or adjusted
and, if damaged or faulty, they must be replaced. The
mounting bracket for the left front impact sensor on
models with a diesel engine is serviced as a unit with
that sensor.
OPERATION
The front impact sensors are electronic accelerom-
eters that sense the rate of vehicle deceleration,
which provides verification of the direction and sever-
ity of an impact. Each sensor also contains an elec-
tronic communication chip that allows the unit to
communicate the sensor status as well as sensor
fault information to the microprocessor in the Airbag
Control Module (ACM). The ACM microprocessor con-
tinuously monitors all of the front passive restraint
system electrical circuits to determine the system
readiness. If the ACM detects a monitored system
fault, it sets a Diagnostic Trouble Code (DTC) and
controls the airbag indicator operation accordingly.
The impact sensors each receive battery current and
ground through dedicated left and right sensor plus and
minus circuits from the ACM. The impact sensors and
the ACM communicate by modulating the voltage in the
sensor plus circuit. The hard wired circuits between the
front impact sensors and the ACM may be diagnosed
and tested using conventional diagnostic tools and pro-
cedures. However, conventional diagnostic methods will
not prove conclusive in the diagnosis of the ACM or the
impact sensors. The most reliable, efficient, and accu-
rate means to diagnose the impact sensors, the ACM,
and the electronic message communication between the
sensors and the ACM requires the use of a DRBIIIt
scan tool. Refer to the appropriate diagnostic informa-
tion.
Fig. 17 Front Impact Sensor
1 - SENSOR
2 - CONNECTOR RECEPTACLE
KJRESTRAINTS 8O - 21

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)

electronic circuitry of the ITM which includes a
microprocessor, and an ultrasonic receive transducer.
A molded plastic connector receptacle containing six
terminal pins that is soldered to a small circuit board
and extends through a clearance hole in the left front
corner of the ITM housing, and an ultrasonic trans-
mit transducer housing extends from the center of
the right side of the ITM housing. Both the transmit
transducer on the right side of the module and the
receive transducer on the ITM circuit board are
aimed through two small round holes in the sight
shield of the trim cover. The ITM is connected to the
vehicle electrical system by a dedicated take out and
connector of the overhead wire harness that is inte-
gral to the headliner.
The ITM unit cannot be adjusted or repaired and,
if faulty or damaged, it must be replaced. The ITM is
serviced as a unit with the trim cover.
OPERATION
The microprocessor in the Intrusion Transceiver
Module (ITM) contains the motion sensor logic cir-
cuits and controls all of the features of the premium
version of the Vehicle Theft Alarm (VTA). The ITM
uses On-Board Diagnostics (OBD) and can communi-
cate with other electronic modules in the vehicle as
well as with the DRBIIItscan tool using the Pro-
grammable Communications Interface (PCI) data bus
network. This method of communication is used by
the ITM to communicate with the Body Control Mod-
ule (BCM) and for diagnosis and testing through the
16-way data link connector located on the driver side
lower edge of the instrument panel. The ITM also
communicates with the alarm siren over a dedicated
serial bus circuit.
The ITM microprocessor continuously monitors
inputs from its on-board motion sensor circuitry as
well as inputs from the BCM and the alarm siren
module. The on-board ITM motion sensor circuitry
transmits ultrasonic signals into the vehicle cabin
through a transmit transducer, then listens to the
returning signals as the bounce off of objects in the
vehicle interior. If an object is moving in the interior,
a detection circuit in the ITM senses this movement
through the modulation of the returning ultrasonic
signals that occurs due to the Doppler effect. The
motion detect function of the ITM can be disabled by
depressing the ªLockº button on the Remote Keyless
Entry (RKE) transmitter three times within fifteen
seconds, while the security indicator is still flashing
rapidly. The ITM will signal the alarm siren module
to provide a single siren ªchirpº as an audible confir-
mation that the motion sensor function has been dis-
abled.
If movement is detected, the ITM sends an elec-
tronic message to the BCM over the PCI data bus toflash the exterior lighting and sends an electronic
message to the alarm siren module over a dedicated
serial bus line to sound the siren. When the BCM
detects a breach in the perimeter protection through
a door, tailgate, flip-up glass, or hood ajar switch
input, it sends an electronic message to the ITM and
the ITM sends an electronic message to the BCM
over the PCI data bus to flash the exterior lighting
and sends an electronic message to the alarm siren
module over a dedicated serial bus line to sound the
siren. The ITM also monitors inputs from the alarm
siren module for siren battery or siren input/output
circuit tamper alerts, and siren battery condition
alerts, then sets active and stored Diagnostic Trouble
Codes (DTC) for any monitored system faults it
detects. 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 ITM. If a fault
does not recur for fifty ignition cycles, the ITM will
automatically erase the stored DTC.
The ITM is connected to the vehicle electrical sys-
tem through a dedicated take out and connector of
the overhead wire harness. The ITM receives battery
current on a fused B(+) circuit through a fuse in the
Junction Block (JB), and receives ground through a
ground circuit and take out of the body wire harness.
This ground take out has a single eyelet terminal
connector that is secured by a ground screw to the
base of the left D-pillar behind the quarter trim
panel. These connections allow the ITM to remain
operational, regardless of the ignition switch position.
The hard wired inputs and outputs for the ITM may
be diagnosed and tested using conventional diagnos-
tic tools and procedures. However, conventional diag-
nostic methods will not prove conclusive in the
diagnosis of the ITM, the PCI data bus network, or
the electronic message inputs to and outputs from
the ITM. The most reliable, efficient, and accurate
means to diagnose the ITM, the PCI data bus net-
work, and the electronic message inputs to and out-
puts from the ITM requires the use of a DRBIIIt
scan tool. Refer to the appropriate diagnostic infor-
mation.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) While pulling downward lightly on either rear
corner of the Intrusion Transceiver Module (ITM)
trim cover, insert a small thin-bladed screwdriver
through each of the service holes on the rear edge of
the trim cover to depress and release the two inte-
gral rear latch features of the module from the
mounting bracket above the headliner (Fig. 11).
(3) Pull the ITM trim cover rearward far enough
to disengage the two integral front latch features of
KJVEHICLE THEFT SECURITY 8Q - 15
INTRUSION TRANSCEIVER MODULE (Continued)