2005 CHRYSLER VOYAGER skreem

The BCM utilizes integrated circuitry and informa-
tion carried on the Programmable Communications
Interface (PCI) data bus network along with many
hard wired inputs to monitor many sensor and
switch inputs throughout the vehicle. In response to
those inputs, the internal circuitry and programming
of the BCM allow it to control and integrate many
electronic functions and features of the vehicle
through both hard wired outputs and the transmis-
sion of electronic message outputs to other electronic
modules in the vehicle over the PCI data bus.
OPERATION
The Body Control Module (BCM) supplies vehicle
occupants with visual and audible information and
controls various vehicle functions. To provide and
receive information, the BCM is interfaced to the
vehicle's serial bus communications network, referred
to as the Programmable Communications Interface
(PCI) bus.
This network consists of the;
²Powertrain Control Module (PCM)
²Transmission Control Module (TCM)
²Mechanical Instrument Cluster (MIC)
²Occupant Restraint Controller (ORC)
²Compass/Mini-Trip Computer (CMTC)
²Electronic Vehicle Information Center (EVIC)
²Controller Antilock Brake (CAB)
²HVAC Control Module
²Sliding Door Control Modules (driver and pas-
senger side doors)
²Power Liftgate Module (PLG)
²Audio system equipped with RAZ, RBU, RBK,
and RBB radios.
²Sentry Key Remote Entry Module (SKREEM).
²Side Impact Airbag Control Module (SIACM)²Memory Seat Module (MSM)
²Sentry Key Immobilizer Module (SKIM)
The BCM is operational when battery power is
supplied to the module.
The BCM provides the following features:
²Power Door Locks
²Automatic Door Locks
²Battery Protection - The BCM will automatically
turn off all exterior lamps after 3 minutes, and all
interior lamps after 15 minutes after the ignition is
turned off, if they are not turned off by the driver.
²Chime Control
²Compass/Mini-Trip support.
²Interior Lighting (Courtesy/Reading Lamps)
²BCM Diagnostic Reporting
²Electronic Liftgate Release (with Power Door
Locks)
²Exterior Lighting
²Headlamp Time Delay (with/without Automatic
Headlamps)
²Illuminated Entry
²Fade to Off Interior Lamps - This feature dims
the interior lighting (courtesy lamps) gradually if the
BCM does not receive any new inputs that would
cause the interior lamps to remain on.
²Pulse Width Modulated Instrument Panel Dim-
ming
²Door Lock Inhibit - This feature disables the
door lock functions if the key is in the ignition and
either front door is ajar. Pressing the Remote Keyless
Entry (RKE) lock/unlock button under these condi-
tions result in normal lock/unlock activation.
The BCM has the ability to LEARN additional fea-
tures in the vehicle, provided the appropriate switch
input and PCI data bus messages are received. Refer
to the LEARNED FEATURES table.
LEARNED FEATURES
FEATURE LEARNING KEY
REAR WIPER CONTROL ON HVAC CONTROL ON
INSTRUMENT PANELPCI BUS MESSAGE RECEIVED FROM HVAC
CONTROL
AUTOMATIC HEADLAMPS PCI MESSAGE FROM OVERHEAD OR HEADLAMP
SWITCH POSITION (AUTO)
REMOTE KEYLESS ENTRY SKREEM MESSAGE RECEIVED FROM MODULE
FRONT FOG LAMPS HEADLAMP SWITCH POSITION (PARK W/FRONT
FOG LAMPS)
POWER SLIDING DOOR PCI IFR RECEIVED FROM MODULE
THE BCM HAS FOUR SWITCH INPUTS FOR THE POWER SLIDING DOOR FEATURE; LOCATED IN THE
OVERHEAD CONSOLE ARE THE LEFT AND RIGHT SIDE SLIDING DOOR SWITCHES TO ACTIVATE EITHER
OR BOTH SLIDING DOORS UNDER THE PROPER CONDITIONS. ALSO ARE B-PILLAR SWITCHES LOCATED
ON THE LEFT AND RIGHT B-PILLAR POSTS.
POWER LIFTGATE PCI IFR RECEIVED FROM MODULE
RSELECTRONIC CONTROL MODULES8E-3
BODY CONTROL MODULE (Continued)

FEATURE LEARNING KEY
THE BCM HAS ONE LIFTGATE INPUT LOCATED IN THE OVERHEAD CONSOLE.
POWER LOCKOUT SWITCH INPUT
THE BCM HAS ONE LOCKOUT SWITCH INPUT THAT WHEN ENABLED WILL DISABLE THE B-PILLAR
SLIDING DOOR SWITCHES FROM ACTIVATING EITHER SLIDING DOOR WHEN DEPRESSED.
PCI AUDIO SYSTEM PCI MESSAGE RECEIVED FROM MODULE
REMOTE RADIO CONTROLS REMOTE RADIO SWITCHES PRESENT
VEHICLE THEFT SECURITY SKREEM MESSAGE RECEIVED, VALID KEY
RECEIVED, & DIAGNOSTIC PID RECEIVED.
MEMORY SEAT AND MIRRORS MEMORY SEAT SWITCH PRESENT AND OR PCI
MESSAGE RECEIVED FROM MEMORY MODULE
ABS W/TRACTION CONTROL PCI MESSAGE RECEIVED FROM CAB
SENTRY KEY IMMOBILIZER SYSTEM PCI MESSAGE RECEIVED FROM SKIM OR VTSS
PRESENT
ADJUSTABLE PEDAL MODULE PCI MESSAGE RECEIVED FROM ADJUSTABLE
PEDAL MODULE (APM)
When replacing a BCM there are three modules
available:
²Base
²Midline
²RG - Export
The Midline controller is used on vehicles that
have Power Door Locks. If a vehicle is equipped with
the Vehicle Theft Security System, the Midline con-
troller becomes a Premium when the theft feature is
enabled.
CAUTION: Do not swap Body Control Modules
between vehicles or body controller's off the shelf.
The BCM has internal diagnostic capability that
assists in diagnosing the system error. When an
OPEN or a SHORT circuit exists, the diagnostic tool
can be used to read the BCM faults. The faults are
very descriptive in identifying the appropriate fea-
ture that has faulted.
The only two faults that the BCM logs that con-
clude the replacement of a BCM are faults;
²# 01 - Internal BCM failure (replace BCM)
²# 1F - J1850 Internal Hardware Failure (replace
BCM)
Otherwise the appropriate diagnostic procedures
for each of the features should be taken when the
BCM logs a fault.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the lower instrument panel silencer.(3) Remove the knee blocker and reinforcement
(Refer to 23 - BODY/INSTRUMENT PANEL/KNEE
BLOCKER REINFORCEMENT - REMOVAL).
(4) Disconnect the five wire connectors from the
bottom of the Body Control Module (BCM).
(5) Move bulkhead wiring aside.
(6) Remove the screws holding the BCM to the
bulkhead.
(7) Remove the BCM from the mounting bracket.
INSTALLATION
(1) Install the BCM to the mounting bracket.
(2) Install the screws holding the BCM to the
bulkhead.
(3) Connect the five wire connectors to the bottom
of the Body Control Module (BCM).
(4) Install the knee blocker and reinforcement
(Refer to 23 - BODY/INSTRUMENT PANEL/KNEE
BLOCKER REINFORCEMENT - INSTALLATION).
(5) Install the lower instrument panel silencer.
(6) Connect the battery negative cable.
(7) Verify proper operation of BCM and its func-
tions.
CONTROLLER ANTILOCK
BRAKE
DESCRIPTION
The controller antilock brake (CAB) is a micropro-
cessor-based device which monitors the antilock
brake system (ABS) during normal braking and con-
trols it when the vehicle is in an ABS stop. The CAB
is mounted to the HCU as part of the integrated con-
trol unit (ICU) (Fig. 1). The CAB uses a 24-way elec-
8E - 4 ELECTRONIC CONTROL MODULESRS
BODY CONTROL MODULE (Continued)

a second time. Pressing the Panic button also acti-
vates the courtesy lamps. Pressing the Panic button
again stops the exterior lamps from flashing and the
horn from sounding. However, the courtesy lamps
will remain illuminated until either the BCM times
out lamp operation or until the turning of the igni-
tion. The panic feature will operate if the ignition is
ON, but only if the Panic button is pressed prior to
starting the vehicle. A vehicle speed of about 25.7
km/h (15 miles-per-hour) will also cancel the panic
event.
The RKE system can also perform other functions
on this vehicle. If the vehicle is equipped with the
optional Vehicle Theft Security System (VTSS), the
RKE transmitter will arm the VTSS when the Lock
button is depressed, and disarm the VTSS when the
Unlock button is depressed.
The RKE system includes two transmitters when
the vehicle is shipped from the factory, but the sys-
tem can retain the vehicle access codes of up to a
total of eight transmitters. If an RKE transmitter is
inoperative or lost, new transmitter vehicle access
codes can be programmed into the system using a
DRB IIItscan tool.
This vehicle also offers several customer program-
mable features, which allows the selection of several
optional electronic features to suit individual prefer-
ences. Customer programmable feature options
affecting the RKE system include:
²Automatic Door Lock- Customer programma-
ble feature that allows the BCM to perform an auto-
matic door lock if the vehicle speed is above 25.7
km/h (15 miles-per-hour).
²Automatic Door Unlock On Exit- Customer
programmable feature that allows the BCM to per-
form an automatic door unlock if the vehicle speed is
0, vehicle in park and driver door is opened.
²Flash Lights with Lock and Unlock- Allows
the option of having the park lamps flash as an opti-
cal verification that the RKE system received a valid
Lock request or Unlock request from the RKE trans-
mitter, or having no optical verification.
²Programming Additional Transmitters-
Allows up to a total of four transmitter vehicle access
codes to be stored.
²Remote Unlock Sequence- Allows the option
of having only the driver side front door unlock when
the RKE transmitter Unlock button is depressed the
first time. The remaining doors unlock when the but-
ton is depressed a second time within 5 seconds of
the first unlock press. Another option is having all
doors unlock upon the first depression of the RKE
transmitter Unlock button.
²Sound Horn on Lock- Allows the option of
having the horn sound a short chirp as an audible
verification that the RKE system received a validLock request from the RKE transmitter, or having no
audible verification.
OPERATION
POWER LOCKS
The Body Control Module (BCM) locks or unlocks
the doors when an actuation input signal from a door
lock switch, Central Lock key cylinder or Remote
Keyless Entry (RKE) is received. The BCM turns on
the output drivers and provides a voltage level to the
door lock motor for a specified time.
REMOTE KEYLESS ENTRY
The RKE transmitter uses radio frequency signals
to communicate with the SKREEM module. The
SKREEM is on the PCI bus. When the operator
presses a button on the transmitter, it sends a spe-
cific request to the SKREEM. In turn, the SKREEM
sends the appropriate request over the PCI bus to
the following:
²Integrated Power Module (IPM)- to activate
the park lamps, the headlamps and the horn for the
horn chirp.
²Power Liftgate Module (PLGM)- to control
the liftgate lock and unlock functions.
After pressing the lock button on the RKE trans-
mitter, all of the door locks will lock, the illuminated
entry will turn off (if all doors are closed) and the
vehicle theft security system (if equipped) will arm.
Pressing the unlock button one time will unlock
the driver door, or all doors based on the customer
programmable feature enabled, the illuminated entry
will turn on the courtesy lamps and the vehicle theft
security system (if equipped) will disarm. Pressing
the unlock button a second time, the remaining door
locks will unlock.
If the vehicle is equipped with the memory system,
the memory message will identify which transmitter
(1 or 2) sent the signal.
ROLLING CODE
The rolling code feature changes part of the trans-
mitter message each time that it is used. The trans-
mitter message and the receiver message increment
together. Under certain conditions with a rolling code
system, such as pressing a button on the RKE trans-
mitter over 255 times outside of receiver range or
replacing the battery, the receiver and transmitter
can fall out of synchronization. To re-synchronize,
press and release the UNLOCK button on the RKE
transmitter repeatedly (it may take up to eight
cycles) while listening carefully for the power door
locks in the vehicle to cycle, indicating that resyn-
chronization has occurred.
RSPOWER LOCKS8N-21
POWER LOCKS (Continued)

VEHICLE THEFT SECURITY
TABLE OF CONTENTS
page page
VEHICLE THEFT SECURITY
DESCRIPTION..........................1
OPERATION............................1
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - SENTRY KEY
REMOTE ENTRY SYSTEM...............3
DIAGNOSIS AND TESTING - VEHICLE
THEFT SECURITY SYSTEM..............3
HOOD AJAR SWITCH - EXPORT
REMOVAL.............................3
INSTALLATION..........................3
SENTRY KEY REMOTE ENTRY MODULE
DESCRIPTION..........................3OPERATION............................4
DIAGNOSIS AND TESTING - SENTRY KEY
REMOTE ENTRY MODULE...............5
REMOVAL.............................6
INSTALLATION..........................6
TRANSPONDER KEY
DESCRIPTION..........................6
OPERATION............................6
STANDARD PROCEDURE - TRANSPONDER
PROGRAMMING.......................6
VTSS/SKIS INDICATOR LAMP
DESCRIPTION..........................8
OPERATION............................8
VEHICLE THEFT SECURITY
DESCRIPTION
VEHICLE THEFT SECURITY SYSTEM
The Vehicle Theft Security System (VTSS) is
designed to protect against whole vehicle theft. The
system monitors vehicle doors, and ignition action for
unauthorized operation (hood and liftgate for RG -
Export). The alarm activates:
²Sounding of the horn
²Flashing of the headlamps/park/tail lamps
²Flashing of the headlamps
²An engine kill feature (with SKREES)
SENTRY KEY REMOTE ENTRY SYSTEM
The Sentry Key Remote Entry System (SKREES)
is available as a factory-installed option on this vehi-
cle. It is designed to provide passive protection
against unauthorized vehicle use by disabling the
engine, after two (2) seconds of running, whenever an
invalid key is used to start the vehicle. The SKIS is
active whenever the ignition is on and does not
require any customer intervention. The primary com-
ponents of the system are the Sentry Key Remote
Entry Module (SKREEM), Sentry Key (integrated
key with tranponder and RKE on a circuit board),
indicator light, Body Control Module (BCM), and the
Powertrain Control Module (PCM). The SKREEM is
mounted to the steering column with the molded,
integral antenna mounted on the ignition housing.
The indicator light, is located in the Mechanical
Instrument Cluster (MIC).
OPERATION
VEHICLE THEFT SECURITY SYSTEM
Upon failure of proper Sentry Key Remote Entry
Module (SKREEM) communication to the PCM, the
PCM will shut off fuel after two seconds of run time.
The engine will not re-crank on the key cycle that
the failure occurred, a full key down sequence must
be performed for the engine to crank again. After six
consecutive fuel shut-offs, the engine will no longer
crank on subsequent key cycles. The failure must be
corrected and a valid communication process between
the SKREEM and the PCM must occur for the
engine to crank and start again.
The electronics for the VTSS are part of the Body
Control Module (BCM). The system is armed when
the vehicle is locked using the:
²Power door lock switches (with any door ajar)
²Remote Keyless Entry integrated key.
²Door Cylinder Lock Switches (RG only).
For vehicles equipped with Sentry Key Remote
Entry System (SKREES), the doors do not have to be
locked to enable the fuel shut off feature.
After the vehicle is locked and the last door is
closed, the set LED indicator in the Mechanical
Instrument Cluster (MIC) will flash quickly for 16
seconds, indicating that arming is in progress. If no
monitored systems are activated during this period,
the system will arm. The LED will extinguish unless
the liftgate is open. If the liftgate is open, the LED
will flash at a slower rate. This indicates that the
system is armed.
RSVEHICLE THEFT SECURITY8Q-1

RG Only- If fault is detected on the driver key
cylinder input, the indicator LED will remain solid
during the arming process, although the system will
still arm.
If the indicator LED does not illuminate at all
upon door closing it indicates that the system is not
arming.
Passive disarming occurs upon normal vehicle
entry by unlocking either door with the remote trans-
mitter (RG - ignition key or remote transmitter). This
disarming will also halt the alarm once it has been
activated.
A tamper alert exists to notify the driver that the
VTSS had been activated. This alert consists of 3
horn pulses when the vehicle is disarmed.
NOTE: The VTSS will not arm by pushing down the
door lock mechanism. This will manually override
the system.
RG Only- For Door Cylinder Lock Switch
Removal and Installation, refer to Electrical, Power
Locks, Door Cylinder Lock Switch.
If the VTSS is triggered, the horn will pulse, head-
lamps/marker lamps will flash, and the VTSS warn-
ing lamp will flash. If BCM determines the threat to
be false and the VTSS is not triggered again, the sys-
tem will shut down and rearm itself after three min-
utes. If a trigger is still active, the alarm will
continue for an additional 15 minutes without the
horn. The VTSS monitors the passenger compart-
ment (for RG - Export it also monitors the engine
compartment. If a malfunction occurs in the engine
compartment, the passenger compartment would still
arm and function normally).
NOTE: System will not arm if passenger compart-
ment is not secure.
NOTE: (RG - Export - If hood is not secure during
the arming sequence, the lamp will stay lit and not
flash. The system will arm with hood not secured
and the liftgate open).
ARMING THE VTSS - METHOD A
(1) With the key removed from the ignition lock
and any door open (excluding liftgate), actuate one of
the following:
²Power door lock button to LOCK,
²Key fob LOCK button
²Driver door lock key cylinder to locked position
(RG Only).
(2) Close all opened doors. Liftgate can remain
open.(3) After the last door is closed, an arming time-
out period of sixteen seconds will start, then the
VTSS will become armed.
ARMING THE VTSS - METHOD B
Actuating the key fob transmitter LOCK button,
key locking the front doors with the doors closed and
the ignition locked will begin the arming time-out
period. If method A, 16 second time-out sequence was
in process when method B was actuated, the 16 sec-
ond time-out will restart from the time of the second
actuation.
If the security lamp does not illuminate at all upon
final door closure, it indicates that the system is not
arming.
The current VTSS status armed or disarmed shall
be maintained in memory to prevent battery discon-
nects from disarming the system.
TRIGGERING THE VTSS
After the VTSS is armed, the following actions will
trigger the alarm:
²Opening any door (liftgate - only if opening via
liftgate button on key fob).
²Opening the hood (RG - Export)
²Turning the ignition to the RUN position.
NOTE: When the VTSS is ARMED, the interior
power door lock switch ªUNLOCKº will be disabled
until the vehicle is disarmed.
CAUTION: The VTSS indicator LED will trigger and
engine will continue to run if the vehicle is
equipped with SKREES and the proper key is used
to start the vehicle. This condition will occur if the
VTSS has been triggered. If valid key is used, VTSS
will disarm
SENTRY KEY REMOTE ENTRY SYSTEM
The SKREES includes keys from the factory which
are pre-programmed. Each SKREEM will recognize a
maximum of eight Sentry Keys. If the customer
would like to own additional keys other than those
provided with the vehicle, they can be purchased
from any authorized dealer. These keys must be pro-
grammed to the SKREEM on the vehicle in order for
the system to recognize them as valid keys. This can
be done by the dealer with a DRBllltscan tool or by
a customer if this feature is available in their market
and they have two (2) valid keys already available to
them. Refer to the Service Procedures portion of this
system for additional details. The SKREES performs
a self-test each time the ignition switch is turned to
the ON position and will store Diagnostic Trouble
Codes (DTC's) if a system malfunction is detected.
8Q - 2 VEHICLE THEFT SECURITYRS
VEHICLE THEFT SECURITY (Continued)

The SKREES can be diagnosed and any stored DTC's
can be retrieved using a DRBllltscan tool as
described in the appropriate Body Diagnostic Proce-
dures information.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - SENTRY KEY
REMOTE ENTRY SYSTEM
WARNING: On vehicles equipped with airbags, refer
to electrical, restraints, warnings, before attempting
component diagnosis or service. Failure to take the
proper precautions could result in accidental airbag
deployment and possible personal injury or death.
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 Remote Entry System (SKREES)
involves the use of a DRBIIITscan tool. Refer to the
proper Body Diagnostic Procedures information.
The Sentry Key Remote Entry System (SKREES)
and the Programmable Communication Interface
(PCI) bus network should be diagnosed using a scan
tool. The scan tool will allow confirmation that the
PCI bus is functional, that the Sentry Key Remote
Entry Module (SKREEM) is placing the proper mes-
sages on the PCI bus, and that the Powertrain Con-
trol Module (PCM) is receiving the PCI bus
messages. Refer to the proper Body Diagnostic Proce-
dures information, and Wiring Diagrams for complete
circuit descriptions and diagrams.
(1) Check the fuses in the Integrated Power Mod-
ule (IPM). If OK, go to Step 2. If not OK, repair the
shorted circuit or component as required and replace
the faulty fuse.
(2) Disconnect and isolate the battery negative
remote cable from the remote terminal. Unplug the
wire harness connector at the SKREEM. Check for
continuity between the ground circuit cavity of the
SKREEM wire harness connector and a good ground.
There should be continuity. If OK, go to Step 3. If not
OK, repair the open circuit to ground as required.
(3) Connect the battery negative cable. Check for
battery voltage at the fused B(+) circuit cavity of the
SKREEM wire harness connector. If OK, go to Step
4. If not OK, repair the open circuit to the fuse in the
IPM as required.
(4) Turn the ignition switch to the ON position.
Check for battery voltage at the fused ignition switch
output (run/start) circuit cavity of the SKREEM wire
harness connector. If OK, use a scan tool and the
proper Body Diagnostic Procedures information tocomplete the diagnosis of the SKREES. If not OK,
repair the open circuit to the fuse in the IPM as
required.
DIAGNOSIS AND TESTING - VEHICLE THEFT
SECURITY SYSTEM
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. Using a
DRBIIItscan tool. Refer to the proper Body Diagnos-
tic Procedures information for test procedures.
HOOD AJAR SWITCH -
EXPORT
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Using a small flat blade screwdriver, pry trig-
ger switch from the bracket on the left fender well.
(3) Disconnect the hood ajar switch from the wire
connector and remove from vehicle.
INSTALLATION
(1) Connect the hood ajar switch to the wire conec-
tor.
(2) Press the hood ajar switch into position on the
bracket located on the left inner fender well.
(3) Reconnect the battery negative cable.
(4) Close the hood and check for proper operation.
SENTRY KEY REMOTE ENTRY
MODULE
DESCRIPTION
The Sentry Key Remote Entry Module (SKREEM)
performs the functions of the Sentry Key Immobilizer
Module (SKIM), Remote Keyless Entry (RKE) Mod-
ule, and the Tire Pressure Monitoring (TPM) System
(previously part of the Electronic Vehicle Information
Center (EVIC).
The SKREEM is located in the same location as
the SKIM was and is mounted the same way. It looks
identical, but has added capabilities.
SENTRY KEY IMMOBILIZER
The Sentry Key Immobilizer System (SKIS)
authenticates an electronically coded Transponder
Key placed into the ignition and sends a valid/invalid
key message to the Powertrain Control Module
RSVEHICLE THEFT SECURITY8Q-3
VEHICLE THEFT SECURITY (Continued)

(PCM) based upon the results. The ªVALID/INVALID
KEYº message communication is performed using a
rolling code algorithm via the Programmable Com-
munication Interface (PCI) data bus. A ªVALID KEYº
message must be sent to the Powertrain Control
Module (PCM) within two seconds of ignition ON to
free the engine from immobilization.
The SKREEM contains a Radio Frequency (RF)
transceiver and a microprocessor. The SKREEM
retains in memory the ID numbers of any Sentry Key
that is programmed to it. The maximum number of
keys that may be programmed to each module is
eight (8). The SKREEM also communicates over the
Programmable Communication Interface (PCI) data
bus with the Powertrain Control Module (PCM), the
Body Control Module (BCM), the Mechanical Instru-
ment Cluster (MIC), and the DRB IIItscan tool. The
SKREEM transmits and receives RF signals through
a tuned antenna enclosed within a molded plastic
ring formation that is integral to the SKREEM hous-
ing. When the SKREEM is properly installed on the
steering column, the antenna ring fits snugly around
the circumference of the ignition lock cylinder hous-
ing. If this ring is not mounted properly, communica-
tion problems may arise in the form of transponder-
related faults.
For added system security, each SKREEM is pro-
grammed with a unique9Secret Key9code. This code
is stored in memory and is sent over the PCI bus to
the PCM and to each key that is programmed to
work with the vehicle. The9Secret Key9code is there-
fore a common element found in all components of
the Sentry Key Immobilizer System (SKIS). In the
event that a SKREEM replacement is required, the
9Secret Key9code can be restored from the PCM by
following the SKIM replacement procedure found in
the DRB IIItscan tool. Proper completion of this
task will allow the existing ignition keys to be repro-
grammed. Therefore, new keys will NOT be needed.
In the event that the original9Secret Key9code can
not be recovered, new ignition keys will be required.
The DRB IIItscan tool will alert the technician if
key replacement is necessary. Another security code,
called a PIN, is used to gain secured access to the
SKREEM for service. The SKREEM also stores in its
memory the Vehicle Identification Number (VIN),
which it learns through a bus message from the
assembly plant tester. The SKIS scrambles the infor-
mation that is communicated between its components
in order to reduce the possibility of unauthorized
SKREEM access and/or disabling.
REMOTE KEYLESS ENTRY (RKE)
The RKE transmitter uses radio frequency signals
to communicate with the SKREEM. The SKREEM is
on the PCI bus. When the operator presses a buttonon the transmitter, it sends a specific request to the
SKREEM. In turn the SKREEM sends the appropri-
ate request over the PCI Bus to the:
²Body Control Module (BCM) to control the door
lock and unlock functions, the liftgate lock and
unlock functions, the arming and disarming of the
Vehicle Theft Security System (VTSS) (if equipped),
and the activation of illuminated entry.
²Integrated Power Module (IPM) to activate the
park lamps, the headlamps, and the horn for horn
chirp. If requested, the BCM sends a request over
the PCI Bus to the:
TIRE PRESSURE MONITORING (TPM)
If equipped with the Tire Pressure Monitoring
(TPM) System, each of the vehicles four wheels will
have a valve stem with a pressure sensor and radio
transmitter built in. Signals from the tire pressure
sensor/transmitter are received and interpreted by
the SKREEM.
A sensor/transmitter in a mounted wheel will
broadcast its detected pressure once per minute
when the vehicle is moving faster than 15 mph (24
km/h). Each sensor/transmitter's broadcast is
uniquely coded so that the SKREEM can determine
the location.
OPERATION
SENTRY KEY IMMOBILIZER
The Sentry Key Remote Entry Module (SKREEM)
receives an encrypted Radio Frequency (RF) signal
from the transponder key. The SKREEM then
decrypts the signal and broadcasts the requested
remote commands to the appropriate modules in the
vehicle over the Programmable Communication
Interface (PCI) data bus. A valid transponder key ID
must be incorporated into the RF signal in order for
the SKREEM to pass the message on to the appro-
priate modules.
Automatic transponder key synchronization is done
by the SKREEM if a valid transponder key is
inserted into the ignition cylinder, and the ignition is
turned ON. This provides a maximum operation win-
dow for RKE functions.
Each Sentry Key Remote Entry System (SKREES)
consists of a SKREEM and a transponder key. Each
system has a secret key code unique to that system.
The secret key is electronically coded in the
SKREEM and in all programmed transponder keys.
It is used for immobilization and RKE functions for
data security. In addition, each transponder key will
have a unique identification. For North America, the
options are a 3-button or 6 button integrated keys.
For Export, the options are 2-button or 5 button key
fobs. (Export does not get the integrated key).
8Q - 4 VEHICLE THEFT SECURITYRS
SENTRY KEY REMOTE ENTRY MODULE (Continued)

When the ignition switch is moved to the RUN
position, the SKREEM transmits an Radio Frequency
(RF) signal to the transponder in the ignition key.
The SKREEM then waits for a response RF signal
from the transponder in the key. If the response
received identifies the key as valid, the SKREEM
sends a9valid key9message to the Powertrain Con-
trol Module (PCM) over the Programmable Commu-
nication Interface (PCI) data bus. If the response
received identifies the key as invalid or no response
is received from the transponder in the ignition key,
the SKREEM sends an9invalid key9message to the
PCM. The PCM will enable or disable engine opera-
tion based upon the status of the SKREEM mes-
sages. It is important to note that the default
condition in the PCM is9invalid key.9Therefore, if no
response is received by the PCM, the engine will be
immobilized after two (2) seconds of running.
The SKREEM also sends indicator light status
messages to the Mechanical Instrument Cluster
(MIC) to operate the light. This is the method used to
turn the light ON solid or to flash it after the indi-
cator light test is complete to signify a fault in the
SKREES. If the light comes ON and stays ON solid
after the indicator light test, this signifies that the
SKREEM has detected a system malfunction and/or
that the SKREES has become inoperative. If the
SKREEM detects an invalid keyORa key-related
fault exists, the indicator light will flash following
the indicator light test. The SKREEM may also
request an audible chime if the customer key pro-
gramming feature is available and the procedure is
being utilized (Refer to 8 - ELECTRICAL/VEHICLE
THEFT SECURITY/TRANSPONDER KEY - STAN-
DARD PROCEDURE).
REMOTE KEYLESS ENTRY (RKE)
After pressing the lock button on the RKE trans-
mitter, all of the door locks will lock, the illuminated
entry will turn off (providing all doors are closed),
and the VTSS (if equipped) will arm. After pressing
the unlock button, on the RKE transmitter, one time,
the driver door lock will unlock, the illuminated
entry will turn on the courtesy lamps, and the VTSS
(if equipped) will disarm. After pressing the unlock
button a second time, the remaining door locks will
unlock. The Electronic Vehicle Information Center
(EVIC) or the DRBIIItscan tool can reprogram this
feature to unlock all of the door locks with one press
of the unlock button. If the vehicle is equipped with
the memory system, the memory message will iden-
tify which transmitter (1 or 2) sent the signal.The SKREEM is capable of retaining up to 8 indi-
vidual access codes (8 transmitters). If the PRNDL is
in any position except park, the SKREEM will dis-
able the RKE. The 4 button transmitter uses
1-CR2032 battery. The minimum battery life is
approximately 4.7 years based on 20 transmissions a
day at 84ÉF (25ÉC). Use the DRBIIItscan tool or the
Miller Tool 9001 RF Detector to test the RKE trans-
mitter. Use the DRBIIItor the customer program-
ming method to program the RKE system. However,
the SKREEM will only allow RKE programming
when the ignition is in the ON position, the PRNDL
is in park position, and the VTSS (if equipped) is dis-
armed.
TIRE PRESSURE MONITORING (TPM)
The SKREEM monitors the signals from the tire
pressure sensor/transmitters and determines if any
tire has gone below the low pressure threshold LOW
TIRE PRESSURE THRESHOLDS table.
LOW TIRE PRESSURE THRESHOLDS
SYSTEM STATUS
INDICATORTIRE PRESSURE
ON 193 kPa (28 PSI)
OFF 227 kPa (33 PSI)
CRITICAL AND NON-CRITICAL SYSTEM ALERTS
CRITICAL:A critical alert will be triggered when
a tire pressure has gone below a set threshold pres-
sure. The EVIC display will display ªX TIRE(S) LOW
PRESSUREº. ªXº will be the number of tires report-
ing low pressure. The message will display for the
duration of the current ignition cycle or until an
EVIC button is pressed. If the display is removed
without correcting the condition, it will reappear 300
seconds to warn the driver of the low pressure condi-
tion.
NON-CRITICAL:A non-critical alert will be trig-
gered when no signal is received from a sensor/trans-
mitter. The EVIC display in the cluster will display
ªSERVICE TIRE SYSTEM SOON.º
DIAGNOSIS AND TESTING - SENTRY KEY
REMOTE ENTRY MODULE
For proper diagnosis and testing of the Sentry Key
Remote Entry Module (SKREEM), use a DRBllltand
refer to the proper Body Diagnostic Procedures infor-
mation.
RSVEHICLE THEFT SECURITY8Q-5
SENTRY KEY REMOTE ENTRY MODULE (Continued)