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)
POWER LOCKS
TABLE OF CONTENTS
page page
POWER LOCKS
DESCRIPTION.........................20
OPERATION...........................21
DOOR CYLINDER LOCK SWITCH - EXPORT
DESCRIPTION.........................22
OPERATION...........................22
DIAGNOSIS AND TESTING
DOOR CYLINDER LOCK SWITCH -
EXPORT............................22
REMOVAL.............................22
INSTALLATION.........................22
DOOR LOCK MOTOR
DIAGNOSIS AND TESTING
DOOR LOCK MOTOR..................23
DOOR LOCK SWITCH
DIAGNOSIS AND TESTING
DOOR LOCK SWITCH..................23
REMOVAL.............................23INSTALLATION.........................23
KEYLESS ENTRY TRANSMITTER
DIAGNOSIS AND TESTING
KEYLESS ENTRY TRANSMITTER.........24
STANDARD PROCEDURE
STANDARD PROCEDURE - HORN CHIRP
PREFERENCE........................24
STANDARD PROCEDURE - BATTERY
REPLACEMENT.......................24
STANDARD PROCEDURE - REMOTE
KEYLESS ENTRY TRANSMITTER
PROGRAMMING......................24
SPECIFICATIONS
SPECIFICATIONS - TRANSMITTER RANGE . 24
SPECIFICATIONS - BATTERY............24
SLIDING DOOR LOCK MOTOR
REMOVAL.............................25
INSTALLATION.........................25
POWER LOCKS
DESCRIPTION
POWER LOCKS
The power lock system allows all of the doors to be
locked or unlocked electrically by operating a switch
on either front door trim panel. The power lock sys-
tem receives non-switched battery current through a
fuse in the Integrated Power Module (IPM), so that
the power locks remain operational, regardless of the
ignition switch position.
The Body Control Module (BCM) locks the doors
automatically when the vehicle is driven beyond the
speed of 25.7 Km/h (15 mph), all doors are closed, the
accelerator pedal is depressed and the door lock actu-
ation had not been previously activated. The rolling
door lock feature is customer programmable.
This vehicle also offers several customer program-
mable features, which allows the selection of several
optional electronic features to suit individual prefer-
ences.
The power lock system for this vehicle can also be
operated remotely using the available Remote Key-
less Entry (RKE) system radio frequency transmit-
ters, if equipped.
AUTOMATIC DOOR LOCKS
When enabled, this feature will lock all of the door
locks if all of the doors are closed and the vehicle
speed goes above 25.7 km/h (15 mph). If a door
unlock has occurred, then the BCM will perform
another auto lock, if the doors did not electrically
unlock, another auto lock will not occur.
DOOR LOCK INHIBIT
When the key is in the ignition (in any switch posi-
tion) and either front door is opened, the door lock
switches LOCK functions are disabled. The
UN-LOCK functions are still functional. This protects
against locking the vehicle with the key still in the
ignition. The RKE key fob will still lock the doors.
After the key is removed from the ignition or the
doors are closed, the power door locks will operate
normally.
REMOTE KEYLESS ENTRY
The Remote Keyless Entry (RKE) system allows
the use of a remote battery-powered radio transmit-
ter to communicate with the BCM to actuate the
power lock system.
The RKE transmitters are also equipped with a
Panic button. If the Panic button on the RKE trans-
mitter is depressed, the horn will sound and the
exterior lights will flash on the vehicle for about
three minutes, or until the Panic button is depressed
8N - 20 POWER LOCKSRS
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)
The lock function works from the RKE transmitter
even in an out of synchronization condition, therefore
it could be verified by pressing the LOCK button on
the RKE key fob.
DOOR CYLINDER LOCK
SWITCH - EXPORT
DESCRIPTION
The Door Cylinder Lock Switch (If equipped) is
used to:
²Unlock/Lock all the doors via the Central Lock-
ing feature.
²Arm/Disarm the Vehicle Theft Security System.
²Trigger the Illuminated Entry feature.
The door cylinder lock switch is mounted to the
rear of the driver door lock cylinder. When installed
on the rear of the cylinder, there is a tab on the lock
cylinder that aligns with the switch to prevent it
from turning. An anti-rotating device. The door cylin-
der lock switch is a one time use switch. Once it is
removed from the rear of the door lock cylinder, it
may not be reinstalled and a new switch must be
used.
OPERATION
When the Door Cylinder Lock Switch is turned
either way using the door key cylinder, the BCM
reads a direct message signal from the switch.
If turning the key cylinder once, toward the front
of the vehicle, this will:
(1) Mechanically unlock the door lock.
(2) Disarm the Vehicle Theft Security System (if
equipped).
(3) Turn on the Illuminated Entry (if equipped) for
approximately 30 seconds.
If the key cylinder is turned to the unlock position
(toward the front of vehicle) twice within two sec-
onds, all the doors and liftgate will unlock (if
equipped with the central locking feature).
To lock the vehicle using the door cylinder lock
switch, turn the key cylinder toward the rear of the
vehicle once. This will lock the door that you are
using the key on. If equipped with the central locking
feature, this will lock all the other doors and liftgate.
Furthermore, this will arm the vehicle theft security
system and turn off the illuminated entry.
DIAGNOSIS AND TESTING
DOOR CYLINDER LOCK SWITCH - EXPORT
Any diagnosis of the power lock system
should begin with the use of the DRB IIItdiag-
nostic tool. For information on the use of theDRB IIIt, refer to the appropriate Diagnostic
Service Manual.
For complete circuit diagrams, refer to the appro-
priate wiring information.
(1) Visually inspect the switch for proper installa-
tion. Make sure it is seated on the rear of the key
cylinder, with the tab of the door key cylinder prop-
erly aligned with the slot on the door cylinder lock
switch.
(2) Disconnect the switch at the harness connector
and check the resistance in each switch position.
CAUTION: Do not disconnect the switch from the
rear of the door key cylinder. This switch is a one
time use switch. Once it is removed from the rear of
the switch, it is not reusable and must be replaced.
Test the switch at the harness connector.
DOOR CYLINDER LOCK SWITCH RESISTANCE
SWITCH POSITION RESISTANCE VALUE
COUNTERCLOCKWISE 5.4K OHMS
NEUTRAL 18.4K OHMS
CLOCKWISE 2K OHMS
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the door trim panel of the effected door
cylinder lock switch (Refer to 23 - BODY/DOOR -
FRONT/TRIM PANEL - REMOVAL).
(3) Close the door window.
(4) Disconnect the door cylinder lock switch wire
connector from the door harness, and wiring clip
from the impact beam.
(5) Remove the outer door handle from the door.
(6) Remove the switch from the key cylinder in the
door handle and remove from vehicle.
INSTALLATION
(1) Install the switch on the key cylinder in the
door handle.
(2) Install the door handle.
(3) Connect the door cylinder lock switch wire con-
nector to the door harness, and the wiring clip to the
impact beam.
(4) Install the door trim panel of the affected door
cylinder lock switch (Refer to 23 - BODY/DOOR -
FRONT/TRIM PANEL - INSTALLATION).
(5) Connect the battery negative cable.
(6) Verify system operation.
8N - 22 POWER LOCKSRS
POWER LOCKS (Continued)
KEYLESS ENTRY
TRANSMITTER
DIAGNOSIS AND TESTING
KEYLESS ENTRY TRANSMITTER
Using special tool 9001, first test to ensure that
the transmitter is functioning. Typical testing dis-
tance is 2.5 centimeters (1 inch) for Asian transmit-
ters and 30.5 centimeters (12 inches) for all others.
To test, position the transmitter as shown (Fig. 2).
Press any transmitter button, then test each button
individually. The tool will beep if a radio signal
strength that lights five or more LED's is detected.
Repeat this test three times. If transmitter fails any
of the test, refer to the Diagnostic Procedures man-
ual.
STANDARD PROCEDURE
STANDARD PROCEDURE - HORN CHIRP
PREFERENCE
DISABLING
The horn chirp can be toggled using a DRB IIItor
by using a programmed Remote Keyless Entry (RKE)
transmitter.
To DISABLE (cancelling) the horn chirp feature,
press and hold the transmitter LOCK button for a
minimum of five seconds. While pressing the LOCK
button in, press the PANIC button. The horn chirp
feature will not function until the above procedure is
repeated.
ENABLING
The horn chirp can be toggled using a DRB IIItor
by using the Remote Keyless Entry (RKE) transmit-
ter.
To ENABLE (reinstate) the horn chirp feature, use
any one of the four programmed integrated key/key
fob transmitters and reverse the above procedures. It
will ENABLE the horn chirp feature for all transmit-
ters.
STANDARD PROCEDURE - BATTERY
REPLACEMENT
(1) With the transmitter buttons facing down, use
a coin to pry the two halves of the transmitter apart.
Make sure not to damage the rubber gasket during
separation of the housing halves.
(2) Remove the battery from the transmitter back
housing holder.
(3) Replace the batteries. Avoid touching the new
batteries with your fingers, Skin oils may cause bat-
tery deterioration. If you touch a battery, clean it off
with rubbing alcohol.
(4) To assemble the transmitter case, snap the two
halves together.
STANDARD PROCEDURE - REMOTE KEYLESS
ENTRY TRANSMITTER PROGRAMMING
(Refer to 8 - ELECTRICAL/VEHICLE THEFT
SECURITY/TRANSPONDER KEY - STANDARD
PROCEDURE) for programming procedures.
SPECIFICATIONS
SPECIFICATIONS - TRANSMITTER RANGE
Normal operation range is up to a distance of 7
meters (23 ft.) of the vehicle. Range may be better or
worse depending on the environment around the
vehicle.
SPECIFICATIONS - BATTERY
The batteries can be removed without special tools
and are readily available at local retail stores. The
recommended battery is Duracell DL 2016 or equiva-
lent, TWO cells are required. Battery life is about
three years minimum.
CAUTION: Do not touch the battery terminals or
handle the batteries any more than necessary.
Hands must be clean and dry.
Fig. 2 TRANSMITTER DIAGNOSIS - TYPICAL
8N - 24 POWER LOCKSRS
(Refer to 8 - ELECTRICAL/HEATED SEATS -
DESCRIPTION) for more information on the heated
seat option. (Refer to 8 - ELECTRICAL/POWER
SEATS - DESCRIPTION - MEMORY SEAT SYS-
TEM) for more information on the memory seat sys-
tem.
The power seat system includes the following com-
ponents:
²Power seat recliners
²Power seat switches
²Power seat tracks
²Circuit breaker
The power seat system with memory and heated
seat options includes the following components:
²Power seat recliner
²Power seat switch
²Power seat track.
²Memory Seat Mirror Module (MSMM)
²Memory set switch
²Heated Seat Module (HSM)
²Heated seat switch
²Electronic Vehicle Information Center (EVIC)
MEMORY SYSTEM
The memory system is able to store and recall the
driver side power seat positions (including the power
recliner position), power adjustable pedal positions
and the driver outside mirror position for two driv-
ers. On vehicles equipped with a factory radio, the
memory system is also able to store and recall radio
station presets for two drivers. The memory system
also will store and recall the last station listened to
for each driver, even if it is not one of the preset sta-
tions.
The memory system will automatically return to
its preset settings when the corresponding numbered
button of the memory switch is depressed, or when
the doors are unlocked using the corresponding
Remote Keyless Entry (RKE) transmitter. A customer
programmable feature of the memory system allows
the RKE recall of memory features to be disabled, if
desired. This programmable feature is internal in the
Electronic Vehicle Information Center (EVIC) mod-
ule, which is located in the overhead console.
A Memory Seat Mirror Module (MSMM) is used to
control and integrate the many electronic functions
and features included in the memory seat and mirror
systems.
The memory system includes the following compo-
nents:
²Memory Seat Mirror Module (MSMM)
²Memory set switch
²Position potentiometers on the driver outside
side view mirror
²Position potentiometers on the power adjustable
pedal motor²Position potentiometers on the driver side power
seat track and power seat recliner motors
²Electronic Vehicle Information Center (EVIC)
²Radio receiver (if PCI data bus capable)
Certain functions of the memory system rely upon
resources shared with other electronic modules in the
vehicle over the Programmable Communications
Interface (PCI) data bus network. Initial diagnosis of
these electronic modules or the PCI data bus network
requires the use of a DRBIIItor equivalent scan tool
and the proper Diagnostic Procedures information. If
this method does not prove conclusive, the proper
wiring schematics and the service manual diagnostic
information are required.
The other electronic modules that may affect mem-
ory system operation are:
²Body Control Module (BCM)- (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/BODY CONTROL/CENTRAL TIMER MODUL
- DESCRIPTION) for additional information.
²Powertrain Control Module (PCM)- (Refer
to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION) for additional information.
²Transmission Control Module (TCM)- (Refer
to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES/TRANSMISSION CONTROL MODULE -
DESCRIPTION) for additional information.
(Refer to 8 - ELECTRICAL/HEATED SEATS -
DESCRIPTION) for additional information on the
heated seat system. (Refer to 8 - ELECTRICAL/
POWER LOCKS - DESCRIPTION) for additional
information on the RKE system.
OPERATION
POWER SEAT SYSTEM
The power seat system receives battery current
through fuse #22 in the Integrated Power Module
(IPM) and a circuit breaker under the front seats,
regardless of the ignition switch position.
When a power seat switch control knob or knobs
are actuated, a battery feed and a ground path are
applied through the switch contacts to the appropri-
ate power seat track adjuster motor. The selected
adjuster motor operates to move the seat track
through its drive unit in the selected direction until
the switch is released, or until the travel limit of the
seat track is reached. When the switch is moved in
the opposite direction, the battery feed and ground
path to the motor are reversed through the switch
contacts. This causes the adjuster motor to run in the
opposite direction.
No power seat switch should be held applied in any
direction after the seat track has reached its travel
limit. The power seat adjuster motor each contain a
8N - 32 POWER SEAT SYSTEMRS
POWER SEAT SYSTEM (Continued)
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).
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. 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 receptacles on the
tail of the clockspring case connect the clockspring to
the vehicle electrical system through two 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 armature. Rubber bumper
blocks on either side of the clockspring tower forma-
tion 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 clock-
spring rotor hub contacts a turn signal cancel actua-
tor of the multi-function switch to provide automatic
turn signal cancellation. The yellow or black-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 surface of the
clockspring rotor to the horn switch and, if the vehi-
cle is so equipped, to the optional speed control
switches and remote radio switches on the steering
wheel.
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 clock-
spring indexes the clockspring tape to the movable
steering components so that the tape can operatewithin 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 rela-
tive to the movable steering components and must be
re-centered following completion of the service or the
tape may be damaged (Refer to 8 - ELECTRICAL/
RESTRAINTS/CLOCKSPRING - STANDARD PRO-
CEDURE).
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 procedure
must be performed (Refer to 8 - ELECTRICAL/RE-
STRAINTS/CLOCKSPRING - STANDARD PROCE-
DURE).
STANDARD PROCEDURE - CLOCKSPRING
CENTERING
If the rotating tape (wire coil) in the clockspring is
not positioned properly with the steering wheel and
the front wheels, the clockspring may fail. The fol-
lowing procedure MUST BE USED to center the
clockspring if it is not known to be properly posi-
tioned, or if the front wheels were moved from the
straight ahead position.
(1) Position steering wheel and front wheels
straight ahead.
(2) Release hood latch and open hood.
(3) Disconnect and isolate the battery negative
cable.
(4) Wait two minutes for the system reserve capac-
itor to discharge before beginning any airbag compo-
nent service.
(5) Remove driver airbag from steering wheel
(Refer to 8 - ELECTRICAL/RESTRAINTS/DRIVER
AIRBAG - REMOVAL).
(6) Disconnect wire connectors from back of driver
airbag.
(7) Disconnect the 2±way connector from remote
radio control harness (if equipped).
(8) Disconnect the 4±way harness connector from
the speed control (if equipped)/horn harness to the
clockspring.
(9) Remove steering wheel (Refer to 19 - STEER-
ING/COLUMN/STEERING WHEEL - REMOVAL).
(10) Rotate the clockspring rotor clockwise until
the rotor stops. Do not apply excessive force.
(11) From the end of travel, rotate the rotor two
turns counterclockwise until the wires end up at the
top.
RSRESTRAINTS8O-11
CLOCKSPRING (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)