2003 DODGE RAM Ignition switch

steering wheel hub area are not pinched between the
driver airbag and the steering wheel armature.
(5) Install and tighten the two screws that secure
the driver airbag to the steering wheel armature.
Tighten the screws to 14 N´m (120 in. lbs.).
(6) From the top of the steering wheel, position the
two trim covers or speed control switches into the
pockets on each side of the driver airbag trim cover.
(7) From the underside of the steering wheel,
install and tighten the two screws that secure the
two trim covers or speed control switches to each side
of the driver airbag trim cover. Tighten the screws to
2 N´m (15 in. lbs.).
(8) Do not reconnect the battery negative cable at
this time. The supplemental restraint system verifi-
cation test procedure should be performed following
service of any supplemental restraint system compo-
nent. (Refer to 8 - ELECTRICAL/RESTRAINTS -
STANDARD PROCEDURE - VERIFICATION TEST).
FRONT CENTER SEAT BELT &
RETRACTOR
REMOVAL
A front center seat belt and retractor is used only
on standard cab models. Quad cab models have a lap
belt in the front center seating position. (Refer to 8 -
ELECTRICAL/RESTRAINTS/FRONT CENTER
SEAT BELT BUCKLE - REMOVAL).
WARNING: DURING AND FOLLOWING ANY SEAT
BELT OR CHILD RESTRAINT ANCHOR SERVICE,
CAREFULLY INSPECT ALL SEAT BELTS, BUCKLES,
MOUNTING HARDWARE, RETRACTORS, TETHER
STRAPS, AND ANCHORS FOR PROPER INSTALLA-
TION, OPERATION, OR DAMAGE. REPLACE ANY
BELT THAT IS CUT, FRAYED, OR TORN.
STRAIGHTEN ANY BELT THAT IS TWISTED.
TIGHTEN ANY LOOSE FASTENERS. REPLACE ANY
BELT THAT HAS A DAMAGED OR INOPERATIVE
BUCKLE OR RETRACTOR. REPLACE ANY BELT
THAT HAS A BENT OR DAMAGED LATCH PLATE
OR ANCHOR PLATE. REPLACE ANY CHILD
RESTRAINT ANCHOR OR THE UNIT TO WHICH THE
ANCHOR IS INTEGRAL THAT HAS BEEN BENT OR
DAMAGED. NEVER ATTEMPT TO REPAIR A SEAT
BELT OR CHILD RESTRAINT COMPONENT.
ALWAYS REPLACE DAMAGED OR FAULTY SEAT
BELT AND CHILD RESTRAINT COMPONENTS WITH
THE CORRECT, NEW AND UNUSED REPLACEMENT
PARTS LISTED IN THE DAIMLERCHRYSLER MOPAR
PARTS CATALOG.
(1) Reach between the center of the front seat
cushion and front seat back to access and unbucklethe front center seat belt lower anchor latch plate
from the unique black, keyed lower anchor buckle.
Use an ignition key or a small screwdriver to depress
the small white release button on the anchor buckle.
(2) Move the front seat to its most forward position
for easiest access to the front center seat belt and
retractor unit.
(3) Using a trim stick or another suitable wide
flat-bladed tool, gently pry at each side of the front
center seat belt bezel on the cab back trim panel to
release the snap features that secure the bezel to the
panel (Fig. 24).
(4) Remove the bezel from the webbing of the front
center seat belt.
(5) Remove the trim from the cab back panel.
(Refer to 23 - BODY/INTERIOR/REAR CAB BACK
PANEL TRIM - REMOVAL).
(6) Remove the two screws that secure the belt
bracket of the front center seat belt to the body
bracket on the upper cab back panel reinforcement
(Fig. 25).
(7) Remove the belt bracket of the front center
seat belt from the body bracket on the upper cab
back panel reinforcement.
(8) Remove the two screws that secure the front
center seat belt retractor bracket to the floor panel
near the base of the cab back panel.
Fig. 24 Front Center Seat Belt Bezel
1 - TRIM PANEL
2 - BODY BRACKET
3 - SEAT BELT BRACKET
4 - SEAT BELT
5 - BEZEL
DRRESTRAINTS 8O - 25
DRIVER AIRBAG (Continued)

PASSENGER AIRBAG ON/OFF
SWITCH
DESCRIPTION
The passenger airbag on/off switch is standard
equipment on all standard cab versions of this model
when they are equipped with the dual front airbag
system (Fig. 35). This switch is a two-position, resis-
tor multiplexed switch with a single integral red
Light-Emitting Diode (LED), and a non-coded key
cylinder-type actuator. The switch is located in the
lower right corner of instrument panel center bezel,
near the center of instrument panel to make the Off
indicator visible to all front seat occupants. When the
switch is in its installed position, the only compo-
nents visible through the dedicated opening of the
cluster bezel are the switch face plate and nomencla-
ture, and the key cylinder actuator. The9Off9position
of the switch is illuminated when this switch position
is selected, while the ªOnº position of the switch is
designated by text imprinted upon the face plate of
the switch, but is not illuminated. The remainder of
the switch is concealed behind the switch face plate
and the instrument panel center bezel.
The passenger airbag on/off switch housing is con-
structed of molded plastic and has three integral
mounting tabs. These mounting tabs are used to
secure the switch to the back of the molded plastic
switch face plate with three small screws. The
molded plastic face plate also has three integral
mounting tabs that are used to secure the switch and
face plate unit to the instrument panel center bezel
with three additional screws. A molded plastic con-
nector receptacle on the back of the switch housingconnects the switch to the vehicle electrical system
through a dedicated take out and connector of the
instrument panel wire harness. The molded plastic
harness connector insulator is keyed and latched to
ensure proper and secure switch electrical connec-
tions. The passenger airbag on/off switch cannot be
adjusted or repaired and, if faulty or damaged, the
switch must be replaced.
OPERATION
The passenger airbag on/off switch allows the cus-
tomer to turn the passenger airbag function On or
Off to accommodate certain uses of the right front
seating position where airbag protection may not be
desired. See the owner's manual in the vehicle glove
box for specific recommendations on when to enable
or disable the passenger airbag. The Off indicator of
the switch will be illuminated whenever the switch is
turned to the Off position and the ignition switch is
in the On position.
The ignition key is the only key or object that
should ever be inserted into the key cylinder actuator
of the switch. The on/off switch requires only a par-
tial key insertion to fully depress a spring-loaded
locking plunger. The spring-loaded locking plunger
prevents the user from leaving the key in the switch.
The key will be automatically ejected when force is
not applied. To actuate the passenger airbag on/off
switch, insert the ignition key into the switch key
actuator far enough to fully depress the plunger, then
rotate the actuator to the desired switch position.
When the switch key actuator is rotated to its clock-
wise stop (the key actuator slot will be aligned with
the Off indicator), the Off indicator is illuminated
and the passenger airbag is disabled. When the
switch is rotated to its counterclockwise stop (the key
actuator slot will be in a vertical position), the Off
indicator will be extinguished and the passenger air-
bag is enabled.
The passenger airbag on/off switch connects one of
two internal resistors in series between the passen-
ger airbag mux switch sense and passenger airbag
mux switch return circuits of the Airbag Control
Module (ACM). The ACM continually monitors the
resistance in these circuits to determine the switch
position that has been selected. When the switch is
in the Off position, the ACM provides a ground input
to the switch through the passenger airbag indicator
driver circuit, which energizes the Light-Emitting
Diode (LED) that illuminates the Off indicator of the
switch.
The ACM will also illuminate the Off indicator of
the switch for about seven seconds each time the
ignition switch is turned to the On position as a bulb
test. The ACM will store a Diagnostic Trouble Code
(DTC) for any fault it detects in the passenger airbag
Fig. 35 Passenger Airbag On/Off Switch
1 - SWITCH
2 - FACE PLATE
3 - OFF INDICATOR
4 - KEY CYLINDER ACTUATOR
8O - 38 RESTRAINTSDR

The seat belt tensioner cannot be repaired and, if
faulty or damaged, the entire outboard front seat belt
and retractor unit must be replaced. If the front air-
bags have been deployed, the seat belt tensioners
have also been deployed. The seat belt tensioner is
not intended for reuse and must be replaced follow-
ing a deployment. A locked retractor that will not
allow the seat belt webbing to be retracted or
extracted is a sure indication that the seat belt ten-
sioner has been deployed and requires replacement.
(Refer to 8 - ELECTRICAL/RESTRAINTS/FRONT
OUTBOARD SEAT BELT & RETRACTOR - REMOV-
AL).
OPERATION
The seat belt tensioners are deployed by a signal
generated by the Airbag Control Module (ACM)
through the driver and passenger seat belt tensioner
line 1 and line 2 (or squib) circuits. When the ACM
sends the proper electrical signal to the tensioners,
the electrical energy generates enough heat to ini-
tiate a small pyrotechnic gas generator. The gas gen-
erator is installed at the top of the tensioner housing
which contains a long metal tape that is routed
through two chambers within the housing. Each end
of the tape is wound around the outer sleeve of a
mechanical clutch mechanism secured to one end of
the torsion bar upon which the retractor spool is
secured. As the gas expands, it is directed against
the metal tape within the two chambers of the hous-
ing causing the tape to unwind from the clutch
sleeve. As the clutch rotates it engages the torsion
bar, which drives the seat belt retractor spool causing
the slack to be removed from the seat belt.
Once a seat belt tensioning sequence has been
completed, the forward momentum of the occupant
results in deformation of the torsion bar. As the tor-
sion bar deforms it allows the seat belt webbing to
unwind from the retractor spool, which causes the
metal tape to be wound back onto the clutch sleeve
until it is pulled tight against two cutter blades
within the housing, which immediately cut the metal
tape.
Removing excess slack from the seat belt not only
keeps the occupant properly positioned for an airbag
deployment following a frontal impact of the vehicle,
but also helps to reduce injuries that the occupant
might experience in these situations as a result of a
harmful contact with the steering wheel, steering col-
umn, instrument panel and/or windshield. The tor-
sion bar is designed to deform in order to control the
loading being applied to the occupant by the seat belt
during a frontal impact, further reducing the poten-
tial for occupant injuries.
The ACM monitors the condition of the seat belt
tensioners through circuit resistance. The ACM willilluminate the airbag indicator in the ElectroMe-
chanical Instrument Cluster (EMIC) and store a
Diagnostic Trouble Code (DTC) for any fault that is
detected. For proper diagnosis of the seat belt ten-
sioners, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.
SEAT BELT TENSION
REDUCER
DESCRIPTION
A seat belt tension reducer is standard equipment
for the driver side front outboard seat belt on stan-
dard cab versions of this model (Fig. 45). The tension
reducer is integral to the driver side front outboard
seat belt and retractor unit, which is secured to the
inner B-pillar on the left side of the vehicle. The
retractor is concealed beneath the molded plastic
inner B-pillar trim. The seat belt tension reducer
consists primarily of a 12-volt Direct Current (DC)
solenoid and an integral connector receptacle that is
located on the forward facing end housing of the
retractor. The seat belt tension reducer is controlled
by a battery current output of the ignition switch and
a ground path provided by the seat belt switch, and
is connected to the vehicle electrical system through
a dedicated take out of the body wire harness by a
keyed and latching molded plastic connector insula-
tor to ensure a secure connection.
The seat belt tension reducer cannot be repaired
and, if faulty or damaged, the entire driver side front
Fig. 45 Seat Belt Tension Reducer
1 - TENSIONER HOUSING OR CHAMBER
2 - GAS GENERATOR
3 - TENSIONER PIGTAIL WIRE
4 - SPOOL
5 - TENSION REDUCER (DRIVER SIDE ON STANDARD CAB
ONLY)
6 - REDUCER CONNECTOR RECEPTACLE
8O - 48 RESTRAINTSDR
SEAT BELT TENSIONER (Continued)

outboard seat belt and retractor unit must be
replaced. (Refer to 8 - ELECTRICAL/RESTRAINTS/
FRONT OUTBOARD SEAT BELT & RETRACTOR -
REMOVAL).
OPERATION
The seat belt tension reducer is controlled by a
ground signal received from the seat belt switch on
the seat belt switch sense circuit and a battery cur-
rent signal received from the ignition switch on the
fused ignition switch output (run-accessory) circuit.
When the seat belt switch is closed (the driver side
front seat belt is fastened) and the ignition switch is
in the On or Accessory positions, the seat belt tension
reducer solenoid is energized. When the solenoid is
energized, it actuates a mechanism within the driver
side front outboard seat belt retractor to reduce the
normal recoil spring tension exerted by the retractor
spool, which is designed to reel in the seat belt web-
bing onto the spool. When the driver side seat belt is
unbuckled or if the ignition switch is turned to any
position except On or Accessory, the tension reducer
solenoid is de-energized and the normal recoil spring
tension of the retractor is restored.
The action of the seat belt tension reducer results
in improved seat belt comfort for the driver. Reducing
the seat belt retractor recoil spring tension is desir-
able on standard cab models of this vehicle and not
on the quad cab model due to the different mounting
position required for the seat belt turning loop on the
B-pillar relative to the driver's seat position on the
standard cab model. The seat belt tension reducer
may be diagnosed using conventional diagnostic tools
and methods.
DIAGNOSIS AND TESTING - SEAT BELT
TENSION REDUCER
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.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINTSYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
SIDE CURTAIN AIRBAG, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT AND ISOLATE THE BATTERY NEGATIVE
(GROUND) CABLE, THEN WAIT TWO MINUTES FOR
THE SYSTEM CAPACITOR TO DISCHARGE BEFORE
PERFORMING FURTHER DIAGNOSIS OR SERVICE.
THIS IS THE ONLY SURE WAY TO DISABLE THE
SUPPLEMENTAL RESTRAINT SYSTEM. FAILURE TO
TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
(1) Disconnect and isolate the battery negative
cable. Disconnect the body wire harness connector for
the seat belt tension reducer from the tension
reducer connector receptacle on the driver side front
outboard seat belt and retractor unit. Using an ohm-
meter, measure the resistance between the seat belt
switch sense circuit terminal pin and the fused igni-
tion switch output (run-accessory) circuit terminal
pin in the tension reducer connector receptacle on
the retractor. Resistance through the tension reducer
solenoid coil should be 53 ohms at 20É C (68É F). If
OK, go to Step 2. If not OK, replace the faulty driver
side front outboard seat belt and retractor unit.
(2) Check for continuity between the seat belt
switch sense circuit cavity of the body wire harness
connector for the seat belt tension reducer and a good
ground. There should be continuity with the driver
side front seat belt buckled, and no continuity with
the driver side front seat belt unbuckled. If OK, go to
Step 3. If not OK, repair the shorted or open seat
belt switch sense circuit between the tension reducer
and the seat belt switch as required.
(3) Reconnect the battery negative cable. Check for
battery current at the fused ignition switch output
(run-accessory) circuit of the body wire harness con-
nector for the seat belt tension reducer. There should
be battery current with the ignition switch in the On
or Accessory positions, and no battery current with
the ignition switch in any other position. If not OK,
repair the shorted or open fused ignition switch out-
put (run-accessory) circuit between the tension
reducer and the ignition switch as required.
DRRESTRAINTS 8O - 49
SEAT BELT TENSION REDUCER (Continued)

(SIACM) and its mounting bracket are secured with
four screws to the inside of each B-pillar behind
(standard cab) or above (quad cab) the front outboard
seat belt retractor, and concealed behind the B-pillar
trim (Fig. 50). Concealed within a hollow in the cen-
ter of the die cast aluminum SIACM housing is the
electronic circuitry of the SIACM which includes a
microprocessor and an electronic impact sensor.
The SIACM housing is secured to a die cast (stan-
dard cab) or stamped steel (quad cab) mounting
bracket, which is unique for the right or left side
application of this component. The SIACM should
never be removed from its mounting bracket. The
housing also receives a case ground through this
mounting bracket when it is secured to the vehicle. A
molded plastic electrical connector receptacle that
exits the top of the SIACM housing connects the unit
to the vehicle electrical system through a dedicated
take out and connector of the body wire harness.
Both the SIACM housing and its electrical connection
are sealed to protect the internal electronic circuitry
and components against moisture intrusion.
The impact sensor internal to the SIACM is cali-
brated for the specific vehicle, and is only serviced as
a unit with the SIACM. The SIACM cannot be
repaired or adjusted and, if damaged or faulty, it
must be replaced.
OPERATION
The microprocessor in the Side Impact Airbag Con-
trol Module (SIACM) contains the side curtain airbag
system logic circuits and controls all of the features
of only the side curtain airbag mounted on the same
side of the vehicle as the SIACM. The SIACM uses
On-Board Diagnostics (OBD) and can communicate
with other electronic modules in the vehicle as well
as with the DRBIIItscan tool using the Programma-
ble Communications Interface (PCI) data bus net-
work. This method of communication is used by the
SIACM to communicate with the Airbag Control
Module (ACM) and for supplemental restraint system
diagnosis and testing through the 16-way data link
connector located on the driver side lower edge of the
instrument panel. The ACM communicates with both
the left and right SIACM over the PCI data bus.
The SIACM microprocessor continuously monitors
all of the side curtain airbag electrical circuits to
determine the system readiness. If the SIACM
detects a monitored system fault, it sets an activeand stored Diagnostic Trouble Code (DTC) and sends
electronic messages to the ACM over the PCI data
bus. The ACM will respond by sending an electronic
message to the EMIC to turn on the airbag indicator,
and by storing a DTC that will indicate whether the
left or the right SIACM has stored the DTC that ini-
tiated the airbag indicator illumination. An active
fault only remains for the current ignition switch
cycle, while a stored fault causes a DTC to be stored
in memory by the SIACM. For some DTCs, if a fault
does not recur for a number of ignition cycles, the
SIACM will automatically erase the stored DTC. For
other internal faults, the stored DTC is latched for-
ever.
The SIACM receives battery current on a fused
ignition switch output (run-start) circuit through a
fuse in the Integrated Power Module (IPM). The
SIACM has a case ground through its mounting
bracket and also receives a power ground through a
ground circuit and take out of the body wire harness.
This take out has a single eyelet terminal connector
that is secured by a ground screw to the body sheet
metal. These connections allow the SIACM to be
operational whenever the ignition switch is in the
Start or On positions. An electronic impact sensor is
contained within the SIACM. The electronic impact
sensor is an accelerometer that senses the rate of
vehicle deceleration, which provides verification of
the direction and severity of an impact. A pre-pro-
grammed decision algorithm in the SIACM micropro-
cessor determines when the deceleration rate as
signaled by the impact sensor indicates a side impact
that is severe enough to require side curtain airbag
protection. When the programmed conditions are
met, the SIACM sends the proper electrical signals to
deploy the side curtain airbag.
The hard wired inputs and outputs for the SIACM
may be diagnosed and tested using conventional
diagnostic tools and procedures. However, conven-
tional diagnostic methods will not prove conclusive in
the diagnosis of the SIACM, the PCI data bus net-
work, or the electronic message inputs to and outputs
from the SIACM. The most reliable, efficient, and
accurate means to diagnose the SIACM, the PCI data
bus network, and the electronic message inputs to
and outputs from the SIACM requires the use of a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.
8O - 54 RESTRAINTSDR
SIDE IMPACT AIRBAG CONTROL MODULE (Continued)

OPERATION
When speed control is selected by depressing the
ON switch, the PCM (the ECM with a diesel engine)
allows a set speed to be stored in its RAM for speed
control. To store a set speed, depress the SET switch
while the vehicle is moving at a speed between 35
and 85 mph. In order for the speed control to engage,
the brakes cannot be applied, nor can the gear selec-
tor be indicating the transmission is in Park or Neu-
tral.
The speed control can be disengaged manually by:
²Stepping on the brake pedal
²Depressing the OFF switch
²Depressing the CANCEL switch.
²Depressing the clutch pedal (if equipped).
NOTE: Depressing the OFF switch or turning off the
ignition switch will erase the set speed stored in
the PCM (the ECM with a diesel engine).
For added safety, the speed control system is pro-
grammed to disengage for any of the following condi-
tions:
²An indication of Park or Neutral
²A rapid increase rpm (indicates that the clutch
has been disengaged)
²Excessive engine rpm (indicates that the trans-
mission may be in a low gear)
²The speed signal increases at a rate of 10 mph
per second (indicates that the coefficient of friction
between the road surface and tires is extremely low)
²The speed signal decreases at a rate of 10 mph
per second (indicates that the vehicle may have
decelerated at an extremely high rate)
Once the speed control has been disengaged,
depressing the RES/ACCEL switch (when speed is
greater than 30 mph) restores the vehicle to the tar-
get speed that was stored in the PCM (the ECM with
a diesel engine).
While the speed control is engaged, the driver can
increase the vehicle speed by depressing the RES/AC-
CEL switch. The new target speed is stored in the
PCM (the ECM with a diesel engine) when the RES/
ACCEL is released. The PCM also has a9tap-up9fea-
ture in which vehicle speed increases at a rate of
approximately 2 mph for each momentary switch
activation of the RES/ACCEL switch.
A ªtap downº feature is used to decelerate without
disengaging the speed control system. To decelerate
from an existing recorded target speed, momentarily
depress the COAST switch. For each switch activa-
tion, speed will be lowered approximately 1 mph.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - VACUUM SUPPLY
TEST
3.7L / 4.7L / 5.9L / 8.0L Gas Powered Engines
3.7L/4.7L/5.9L/8.0L gas powered engines: actual
engine vacuum, a vacuum reservoir, a one-way check
valve and vacuum lines are used to supply vacuum to
the speed control servo.
(1) Disconnect vacuum hose at speed control servo
and install a vacuum gauge into the disconnected
hose.
(2) Start engine and observe gauge at idle. Vac-
uum gauge should read at least ten inches of mer-
cury.
(3) If vacuum is less than ten inches of mercury,
determine source of leak. Check vacuum line to
engine for leaks. Also check actual engine intake
manifold vacuum. If manifold vacuum does not meet
this requirement, check for poor engine performance
and repair as necessary.
(4) If vacuum line to engine is not leaking, check
for leak at vacuum reservoir. To locate and gain
access to reservoir, refer to Vacuum Reservoir Remov-
al/Installation in this group. Disconnect vacuum line
at reservoir and connect a hand-operated vacuum
pump to reservoir fitting. Apply vacuum. Reservoir
vacuum should not bleed off. If vacuum is being lost,
replace reservoir.
(5) Verify operation of one-way check valve and
check it for leaks.
(a) Locate one-way check valve. The valve is
located in vacuum line between vacuum reservoir
and engine vacuum source. Disconnect vacuum
hoses (lines) at each end of valve.
(b) Connect a hand-operated vacuum pump to
reservoir end of check valve. Apply vacuum. Vac-
uum should not bleed off. If vacuum is being lost,
replace one-way check valve.
(c) Connect a hand-operated vacuum pump to
vacuum source end of check valve. Apply vacuum.
Vacuum should flow through valve. If vacuum is
not flowing, replace one-way check valve. Seal the
fitting at opposite end of valve with a finger and
apply vacuum. If vacuum will not hold, diaphragm
within check valve has ruptured. Replace valve.
5.7 Gas
Vacuum is not used for any part of the speed con-
trol system if equipped with a 5.7L V-8 engine.
5.9L Diesel Engine With Manual Trans.
Vacuum is not used for any part of the speed con-
trol system if equipped with a diesel engine and a
manual transmission.
8P - 2 SPEED CONTROLDR
SPEED CONTROL (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)