2003 DODGE RAM keyless

drivers and provides a voltage level to the door lock
motor for a specified time. All passenger doors can be
locked or unlocked using a mechanical button
mounted on the door trim panel. The front passenger
doors can be locked or unlocked by using the key cyl-
inder.
AUTOMATIC DOOR LOCKS
When the automatic door locks are ENABLED the
door locks will lock when the vehicle is moving at
about 25.7 Km/h (15 mph), all doors are closed and
the accelerator pedal is depressed. This feature can
be switched ON or OFF as desired. When the system
is DISABLED the door locks will operate normally,
but will not lock automatically when the vehicle is
rolling. Once the automatic door locks have been
actuated, they will not try to lock the doors again
until a door is opened.
DOOR LOCK INHIBIT
If the key is in the ignition, in any position, and
either front door is ajar, the doors can not be locked,
but the unlock function still operates. Pressing the
RKE lock/unlock button under these conditions will
result in a normal lock/unlock activation.
After the key is removed from the ignition switch,
or the doors are closed, the power door locks will
operate normally.
DOOR LOCK CIRCUIT PROTECTION
If the door lock switch is actuated continuously for
more than five seconds the instrument cluster will
turn the output driver OFF (the instrument cluster
would consider the switch stuck). Each lock motor is
protected with a Positive Temperature Coefficient
device that prevents motor burn out.
REMOTE KEYLESS ENTRY
²LOCK: Pressing the LOCK button locks all
doors, sounds horn (chirp) once if enabled, flashes the
park lamps once if enabled, and arms the Vehicle
Theft Security System (VTSS), if enabled. The chirp
verifies that the RKE module has sent a message to
the instrument cluster for door lock operation. If a
door has not been closed before pressing the LOCK
button, the vehicle may not be secured and the VTSS
(if equipped) will not arm until the door is closed.
²UNLOCK: Pressing the UNLOCK button once
will unlock the driver's door first if enabled, flashes
the park lamps twice if enabled, activates the illumi-
nated entry system, and disarms the Vehicle Theft
Security System (VTSS), if equipped. Pressing the
UNLOCK button twice within five seconds will
unlock all doors, if driver's door first is enabled.
²PANIC: Pressing the PANIC button sounds the
horns at half second intervals, flashes the exteriorlamps, and turns ON the interior lamps. The panic
alarm will remain on for three minutes, or until the
PANIC button is actuated again or the vehicle speed
exceeds 25.7 Km/h (15 mph) will cancel the panic
event.
The Remote Keyless Entry Module is capable of
retaining the transmitter Vehicle Access Code(s) in
its memory even after vehicle power has been inter-
rupted.
DIAGNOSIS AND TESTING - POWER LOCKS
The most reliable, efficient, and accurate
means to diagnose the power lock system
requires the use of a DRBIIItscan tool and the
proper Diagnostic Procedures manual. The
DRBIIItscan tool can provide confirmation
that the PCI data bus is functional, that all of
the electronic modules are sending and receiv-
ing the proper messages on the PCI data bus,
and that the power lock motors are being sent
the proper hard wired outputs by the relays for
them to perform their power lock system func-
tions.
Following are tests that will help to diagnose the
hard wired components and circuits of the power lock
system. However, these tests may not prove conclu-
sive in the diagnosis of this system. In order to
obtain conclusive testing of the power lock system,
the Programmable Communications Interface (PCI)
data bus network and all of the electronic modules
that provide inputs to, or receive outputs from the
power lock system components must be checked.
The instrument cluster will set Diagnostic Trouble
Codes (DTC) for the power lock system.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
PRELIMINARY DIAGNOSIS
As a preliminary diagnosis for the power lock sys-
tem, note the system operation while you actuate
both the Lock and Unlock functions with the power
lock switches and with the Remote Keyless Entry
(RKE) transmitter. Then, proceed as follows:
²If the entire power lock system fails to function
with either the power lock switches or the RKE
transmitter, check the fused B(+) fuse in the Inte-
grated Power Module (IPM).
²If the power lock system functions with both
power lock switches, but not with the RKE transmit-
ter, proceed to diagnosis of the Remote Keyless Entry
(RKE) system. (Refer to 8 - ELECTRICAL/POWER
LOCKS/KEYLESS ENTRY TRANSMITTER - DIAG-
DRPOWER LOCKS 8N - 3
POWER LOCKS (Continued)

NOSIS AND TESTING) or (Refer to 8 - ELECTRI-
CAL/POWER LOCKS/REMOTE KEYLESS ENTRY
MODULE - DIAGNOSIS AND TESTING).
²If the power lock system functions with the RKE
transmitter, but not with one or both power lock
switches, proceed to diagnosis of the door lock
switches. (Refer to 8 - ELECTRICAL/POWER
LOCKS/POWER LOCK SWITCH - DIAGNOSIS AND
TESTING).
²If the driver side power lock switch operates
only the driver side front door power lock motor, but
all other power lock motors operate with the passen-
ger side power lock switch or the RKE transmitter,
use a DRBIIItscan tool and the appropriate diagnos-
tic information to diagnose the Programmable Com-
munications Interface (PCI) data bus.
²If only one power lock motor fails to operate
with both power lock switches and the RKE trans-
mitter, proceed to diagnosis of the power lock motor.
(Refer to 8 - ELECTRICAL/POWER LOCKS/POWER
LOCK MOTOR - DIAGNOSIS AND TESTING).
POWER LOCK SWITCH
DIAGNOSIS AND TESTING - POWER LOCK
SWITCH
The Light-Emitting Diode (LED) illumination lamp
of the power lock switch receives battery current
through a fuse in the Integrated Power Module (IPM)
on a fused ignition switch output (run) circuit. The
power lock switch on the driver side front door trim
panel is integral to the driver door module. (Refer to
8 - ELECTRICAL/POWER LOCKS/DOOR MODULE
- DIAGNOSIS AND TESTING). If the power lock
switch operates, but the LED is inoperative, check
for battery current at the switch with the ignition
switch in the On position. If OK, replace the faulty
switch. Refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, details
of wire harness routing and retention, connector pin-
out information and location views for the various
wire harness connectors, splices and grounds.
(1) Disconnect and isolate the battery negative
cable. Remove the power lock switch from the door
trim panel. Disconnect the door wire harness connec-
tor for the power lock switch from the switch connec-
tor receptacle.
(2) Test the power lock switch resistance. See the
Power Lock Switch Test chart to determine if the
resistance is correct for the switch in each switch
position (Fig. 1). If not OK, replace the faulty power
lock switch as required.
REMOVAL
The power lock switch on the driver side front door
trim panel is integral to the driver door module.
(Refer to 8 - ELECTRICAL/POWER LOCKS/DOOR
MODULE - REMOVAL).
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the door trim panel (Refer to 23 -
BODY/DOOR - FRONT/TRIM PANEL - REMOVAL).
(3) Remove the switch from the trim panel bezel.
INSTALLATION
(1) Insert switch to trim panel bezel.
(2) Install door trim panel (Refer to 23 - BODY/
DOOR - FRONT/TRIM PANEL - INSTALLATION).
(3) Connect battery negative cable.
Fig. 1 Power Lock Switch Connector Receptacle
POWER LOCK SWITCH TEST TABLE
SWITCH POSITION RESISTANCE BETWEEN
PINS1&5
NEUTRAL 10 KILOHMS  1%
LOCK 820 OHMS  5%
UNLOCK 330 OHMS  5%
8N - 4 POWER LOCKSDR
POWER LOCKS (Continued)

DRIVER DOOR MODULE SWITCH TESTS
POWER LOCK SWITCH
SWITCH POSITIONRESISTANCE BETWEEN
CONNECTOR C-1 PINS
7&11
NEUTRAL 10 KILOHMS   1%
LOCK 820 OHMS   5%
UNLOCK 330 OHMS   5%
POWER MIRROR SWITCH
SWITCH POSITIONCONTINUITY BETWEEN
PINS OF CONNECTOR
C-2
LEFT MIRROR SELECTED
UP PINS1&3
DOWN PINS2&3
RIGHT PINS2&3
LEFT PINS3&6
RIGHT MIRROR SELECTED
UP PINS3&7
DOWN PINS2&3
RIGHT PINS2&3
LEFT PINS3&4
POWER WINDOW SWITCH
SWITCH POSITION CONTINUITY BETWEEN
PINS OF CONNECTOR
C-1
NEUTRAL PINS1&8,PINS2&8,
PINS3&8,PINS4&8,
PINS5&8,PINS6&8,
PINS 8 & 10, PINS 8 &
12
LEFT FRONT UP PINS5&9
DRIVER DOOR MODULE SWITCH TESTS
LEFT FRONT DOWN PINS9&12
RIGHT FRONT UP PINS3&9
RIGHT FRONT DOWN PINS6&9
LEFT REAR UP PINS4&9
LEFT REAR DOWN PINS9&10
RIGHT REAR UP PINS2&9
RIGHT REAR DOWN PINS1&9
POWER WINDOW LOCKOUT SWITCH
SWITCH POSITION CONTINUITY BETWEEN
OFF (SWITCH BUTTON
RAISED - NOT
DEPRESSED)PIN 9 OF CONNECTOR
C-1&PIN8OF
CONNECTOR C-2
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the door trim panel (Refer to 23 -
BODY/DOOR - FRONT/TRIM PANEL - REMOVAL).
(3) Remove the driver door module from the trim
panel bezel.
INSTALLATION
(1) Install driver door module to trim panel bezel.
(2) Install door trim panel (Refer to 23 - BODY/
DOOR - FRONT/TRIM PANEL - INSTALLATION).
(3) Connect battery negative cable.
REMOTE KEYLESS ENTRY
MODULE
DESCRIPTION
When an RKE lock message is sent to the instru-
ment cluster, the instrument cluster actuates the
door locks, the interior lighting is turned off, the
horn chirps (if this feature is enabled), the park
lamps flash (if this feature is enabled) and, if the
vehicle is so equipped, the Vehicle Theft Security
System (VTSS) is armed. When an RKE unlock mes-
sage is sent to the instrument cluster, the instrument
cluster actuates the driver side front door (or all
doors if this feature is enabled) unlock, the interior
lighting is turned on and, if the vehicle is so
equipped, the VTSS is disarmed.
When an RKE panic message is sent to the instru-
ment cluster, the instrument cluster actuates the
driver side front door (or all doors if this feature is
enabled) unlock, the interior lighting is turned on
and, if the vehicle is so equipped, the VTSS is dis-
armed. The panic message will also cause the exte-
rior lamps (including the headlights) to flash, and
Fig. 3 Driver Door Module Connector C2 Receptacle
DRPOWER LOCKS 8N - 7
DRIVER DOOR MODULE (Continued)

the horn to sound for about three minutes, or until a
second panic message is sent to the instrument clus-
ter. A vehicle speed of about 25.7 kilometers-per-hour
(15 miles-per-hour) will also cancel the panic event.
Refer to the owner's manual for more information
on the features, use and operation of the RKE sys-
tem.
OPERATION
Whenever the vehicle battery power is interrupted,
the Remote Keyless Module (RKE) Module will retain
all vehicle access codes in its memory. When replac-
ing or adding a key fob transmitter (maximum of 4) a
DRB IIItscan tool is required to program the RKE
Module to accept the new Vehicle Access Code if a
customer owned transmitter is not available.
If a functioning transmitter is available, (Refer to 8
- ELECTRICAL/POWER LOCKS/KEYLESS ENTRY
TRANSMITTER - STANDARD PROCEDURE)
DIAGNOSIS AND TESTING - REMOTE KEYLESS
ENTRY MODULE
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. Refer to the
proper Body Diagnostic Procedures Manual for test-
ing the Remote Keyless Entry system using a DRB
IIItscan tool.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument cluster (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - REMOV-
AL).
(3) Remove remote keyless entry module from
instrument cluster (Fig. 4).
INSTALLATION
(1) Install remote keyless entry module to instru-
ment cluster.
(2) Install instrument cluster (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - INSTALLA-
TION).
(3) Connect the battery negative cable.
REMOTE KEYLESS ENTRY
TRANSMITTER
DIAGNOSIS AND TESTING - REMOTE 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. 5).
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.
Fig. 4 REMOTE KEYLESS ENTRY MODULE
1 - INSTRUMENT CLUSTER
2 - REMOTE KEYLESS ENTRY MODULE
Fig. 5 TRANSMITTER DIAGNOSIS
8N - 8 POWER LOCKSDR
REMOTE KEYLESS ENTRY MODULE (Continued)

STANDARD PROCEDURE
STANDARD PROCEDURE - RKE TRANSMITTER
BATTERIES
NOTE: Do not disturb the metal terminal near the
batteries. Avoid touching the new batteries. Skin
oils may cause battery deterioration. If batteries are
touched, clean with rubbing alcohol.
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. Be
careful not to damage the rubber gasket when sepa-
rating the case halves.
(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 3V lithium
2016 cell. Install the batteries with the positive ter-
minal up. Reference the ª+ SIDE UPº on the inside of
the bottom half of the transmitter case.
(5) Align the two RKE transmitter case halves
with each other, and squeeze them firmly and evenly
together until they snap back into place. Test trans-
mitter operation.
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 that is already programmed to the vehicle.
To DISABLE (cancel) the horn chirp feature:
(1) Enter the vehicle and close all doors.
(2) Fasten the seat belt (this will cancel the seat
belt chime).
(3) Turn the ignition to the ON position.
(4) Press and hold the LOCK button for 4 seconds.
Within 6 seconds with the LOCK button still
depressed, press the UNLOCK button. When a single
chime is heard, release both buttons.
(5) Turn the ignition OFF.
(6) Turn the ignition ON or wait 60 seconds.(7) Test the horn chirp feature by pressing the
LOCK button.
If a chime is not heard, program mode was can-
celed before the feature could be disabled. If neces-
sary, repeat the procedure.
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 that is already programmed to the vehicle.
To DISABLE (cancel) the optical chirp feature:
(1) Enter the vehicle and close all doors.
(2) Fasten the seat belt (this will cancel the seat
belt chime).
(3) Turn the ignition to the ON position.
(4) Press and hold the LOCK button for 4 seconds.
Within 6 seconds with the LOCK button still
depressed, press the PANIC button. When a single
chime is heard, release both buttons.
(5) Turn the ignition OFF.
(6) Turn the ignition ON or wait 60 seconds.
(7) Test the optical chirp feature by pressing the
LOCK button.
If a chime is not heard, program mode was can-
celed before the feature could be disabled. If neces-
sary, repeat the procedure.
To ENABLE the optical chirp feature, repeat the
above procedure.
UNLOCK SEQUENCE
The unlock sequence can be toggled using a DRB
IIItor by using the Remote Keyless Entry (RKE)
transmitter that is already programmed to the vehi-
cle.
To toggle between Driver door first and Unlock all
doors function:
(1) Enter the vehicle and close all doors.
(2) Fasten the seat belt (this will cancel the seat
belt chime).
(3) Turn the ignition to the ON position.
(4) Press and hold the UNLOCK button for 4 sec-
onds. Within 6 seconds with the UNLOCK button
still depressed, press the LOCK button. When a sin-
gle chime is heard, release both buttons.
(5) Turn the ignition OFF.
(6) Turn the ignition ON or wait 60 seconds.
If a chime is not heard, program mode was can-
celed before the feature could be disabled. If neces-
sary, repeat the procedure.
To toggle this feature, repeat the above procedure.
DRPOWER LOCKS 8N - 9
REMOTE KEYLESS ENTRY TRANSMITTER (Continued)

STANDARD PROCEDURE - RKE TRANSMITTER
PROGRAMING
New Remote Keyless Entry (RKE) transmitters can
be programed using the DRB IIItscan tool and the
proper Diagnostic Procedures manual. The DRB IIIt
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
programmed transmitter is available:
NOTE: When entering program mode using that
programmed fob, ALL currently programmed fobs
will be erased and they will have to be repro-
grammed for the vehicle. If program mode is
entered and no action is performed, the previously
programmed fobs will continue to function.
(1) Enter the vehicle and close all doors.
(2) Fasten the seat belt (this will cancel the seat
belt chime). Turn the ignition to the RUN position.
(3) Press and hold the UNLOCK button on a pro-
grammed transmitter for 4 to 10 seconds. Within the
4 to 10 seconds with the UNLOCK button still
depressed, press the PANIC button for one second.
When a single chime is heard, release both button-
s.The chime indicates the system is in program
mode.(4) Press and release both the LOCK and
UNLOCK buttons simultaneously on a fob to be pro-
grammed. A single chime will be heard, this indicates
the fob has been recognized.
(5) Press and release any button on the same fob.
A single chime will be heard, this indicates the fob
has been programmed.
(6) Repeat steps 4 and 5 for up to a total of 4 fobs.
(7) Turn the ignition OFF.
(8) Turn the ignition ON or wait 60 seconds.
The vehicle will remain in program mode for up to
60 seconds from when the original chime (step 3) was
heard. After 60 seconds, all programmed transmitters
will function normally.
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.
8N - 10 POWER LOCKSDR
REMOTE KEYLESS ENTRY TRANSMITTER (Continued)

VEHICLE THEFT SECURITY
TABLE OF CONTENTS
page page
VEHICLE THEFT SECURITY
DESCRIPTION
DESCRIPTION........................1
SENTRY KEY IMMOBILIZER SYSTEM (SKIS) . 1
DESCRIPTION........................1
OPERATION
OPERATION..........................2
OPERATION..........................2
OPERATION..........................2
DIAGNOSIS AND TESTING
VEHICLE THEFT SECURITY SYSTEM......3STANDARD PROCEDURE
CONFIGURING A NEW MODULE / SWITCH
OPERATING MODES....................3
SENTRY KEY IMMOBILIZER SYSTEM
INITIALIZATION........................3
SENTRY KEY IMMOBILIZER SYSTEM
TRANSPONDER PROGRAMMING..........4
SENTRY KEY IMMOBILIZER SYSTEM
INDICATOR LAMP
DESCRIPTION..........................5
OPERATION............................5
VEHICLE THEFT SECURITY
DESCRIPTION
DESCRIPTION
The Vehicle Theft/Security System (VTSS) is
designed to protect against whole vehicle theft. The
system monitors the vehicle doors and ignition for
unauthorized operation.
The VTSS activates:
²Sounding of the horn
²Flashing of the park lamps
²Flashing of the head lamps
The Remote Keyless Entry (RKE) has 1 mode of
operation,CUSTOMER USAGEmode. The cus-
tomer usage mode provides full functionality of the
module and is the mode in which the RKE module
should be operating when used by the customer.
SENTRY KEY IMMOBILIZER SYSTEM (SKIS)
The Sentry Key Immobilizer System (SKIS) is
designed to provide passive protection against unau-
thorized vehicle use by preventing the engine from
operating while the system is armed. The primary
components of this system are the Sentry Key Immo-
bilizer Module (SKIM), the Sentry Key transponder,
the Vehicle Theft/Security System (VTSS) indicator
LED, and the Powertrain Control Module (PCM).
The SKIM is installed on the steering column near
the ignition lock cylinder. The transponder is located
under the molded rubber cap on the head of the igni-tion key. The VTSS indicator LED is located in the
instrument cluster.
The SKIS includes two valid Sentry Key transpon-
ders from the factory. This is so the customer can self
program new keys if one is lost. If the customer
wishes, additional non-coded blank Sentry Keys are
available. These blank keys can be cut to match a
valid ignition key, but the engine will not start
unless the key transponder is also programmed to
the vehicle. The SKIS will recognize no more than
eight valid Sentry Key transponders at any one time.
The SKIS performs a self-test each time the igni-
tion switch is turned to the ON position, and will
store Diagnostic Trouble Codes (DTC's) if a system
malfunction is detected. The SKIS can be diagnosed,
and any stored DTC can be retrieved using a
DRBIIItscan tool as described in the proper Body
Diagnostic Procedures Manual.
DESCRIPTION
The Sentry Key Immobilizer Module (SKIM) con-
tains a Radio Frequency (RF) transceiver and a cen-
tral processing unit, which includes the Sentry Key
Immobilizer System (SKIS) program logic. The SKIS
programming enables the SKIM to program and
retain in memory the codes of at least two, but no
more than eight electronically coded Sentry Key
transponders. The SKIS programming also enables
the SKIM to communicate over the Programmable
Communication Interface (PCI) bus network with the
Powertrain Control Module (PCM), and/or the
DRBIIItscan tool.
DRVEHICLE THEFT SECURITY 8Q - 1

OPERATION
OPERATION
When in theCustomer Usagemode of operation,
the system is armed when the vehicle is locked using
the:
²Power Door Lock Switches
²Remote Keyless Entry (RKE) Transmitter
²Key Cylinder Switches
After the vehicle is locked and the last door is
closed, the VTSS indicator in the instrument cluster
will flash quickly for 16 seconds, indicating that the
arming is in process. After 16 seconds, the LED will
continue to flash at a slower rate indicating that the
system is armed.
VTSS disarming occurs upon normal vehicle entry
by unlocking either door via the key cylinder or RKE
transmitter, or by starting the vehicle with a valid
Sentry Key. This disarming will also halt the alarm
once it has been activated.
A tamper alert exists to notify the driver that the
system has been activated. This alert consists of 3
horn pulses and the security telltail flashing for 30
seconds when the vehicle is disarmed. The tamper
alert will not occur if disarmed while alarming.
The VTSS will not arm by mechanically locking the
vehicle doors. This will manually override the sys-
tem.
OPERATION
The SKIS includes two valid Sentry Key transpon-
ders from the factory. These two Sentry Keys can be
used to program additional non-coded blank Sentry
Keys. These blank keys can be cut to match a valid
ignition key, but the engine will not start unless the
key transponder is also programmed to the vehicle.
The SKIS will recognize no more than eight valid
Sentry Key transponders at any one time.
The SKIS performs a self-test each time the igni-
tion switch is turned to the ON position, and will
store Diagnostic Trouble Codes (DTC's) if a system
malfunction is detected. The SKIS can be diagnosed,
and any stored DTC can be retrieved using a
DRBIIItscan tool as described in the proper Power-
train Diagnostic Procedures manual.
OPERATION
The SKIM transmits and receives RF signals
through a tuned antenna enclosed within a molded
plastic ring formation that is integral to the SKIM
housing. When the SKIM is properly installed on the
steering column, the antenna ring is oriented around
the circumference of the ignition lock cylinder hous-
ing. This antenna ring must be located within eight
millimeters (0.31 inches) of the Sentry Key in orderto ensure proper RF communication between the
SKIM and the Sentry Key transponder.
For added system security, each SKIM is pro-
grammed with a unique ªSecret Keyº code and a
security code. The SKIM keeps the ªSecret Keyº code
in memory. The SKIM also sends the ªSecret Keyº
code to each of the programmed Sentry Key tran-
sponders. The security code is used by the assembly
plant to access the SKIS for initialization, or by the
dealer technician to access the system for service.
The SKIM also stores in its memory the Vehicle
Identification Number (VIN), which it learns through
a PCI bus message from the PCM during initializa-
tion.
The SKIM and the PCM both use software that
includes a rolling code algorithm strategy, which
helps to reduce the possibility of unauthorized SKIS
disarming. The rolling code algorithm ensures secu-
rity by preventing an override of the SKIS through
the unauthorized substitution of the SKIM or the
PCM. However, the use of this strategy also means
that replacement of either the SKIM or the PCM
units will require a system initialization procedure to
restore system operation.
When the ignition switch is turned to the ON or
START positions, the SKIM transmits an RF signal
to excite the Sentry Key transponder. The SKIM then
listens for a return RF signal from the transponder
of the Sentry Key that is inserted in the ignition lock
cylinder. If the SKIM receives an RF signal with
valid ªSecret Keyº and transponder identification
codes, the SKIM sends a ªvalid keyº message to the
PCM over the PCI bus. If the SKIM receives an
invalid RF signal or no response, it sends ªinvalid
keyº messages to the PCM. The PCM will enable or
disable engine operation based upon the status of the
SKIM messages.
The SKIM also sends messages to the Instrument
Cluster which controls the VTSS indicator. The
SKIM sends messages to the Instrument Cluster to
turn the indicator on for about three seconds when
the ignition switch is turned to the ON position as a
ªbulbº test. After completion of the ªbulbº test, the
SKIM sends bus messages to keep the indicator off
for a duration of about one second. Then the SKIM
sends messages to turn the indicator on or off based
upon the results of the SKIS self-tests. If the VTSS
indicator comes on and stays on after the ªbulb testº,
it indicates that the SKIM has detected a system
malfunction and/or that the SKIS has become inoper-
ative.
If the SKIM detects an invalid key when the igni-
tion switch is turned to the ON position, it sends
messages to flash the VTSS indicator. The SKIM can
also send messages to flash the indicator to serve as
an indication to the customer that the SKIS has been
8Q - 2 VEHICLE THEFT SECURITYDR
VEHICLE THEFT SECURITY (Continued)