Dodge Dakota (R1). Manual - part 291

compressor clutch engagement and idle speed. The
PCM can adapt its programming to meet changing
operating conditions.

The PCM receives input signals from various

switches and sensors. Based on these inputs, the
PCM regulates various engine and vehicle operations
through different system components. These compo-
nents are referred to as Powertrain Control Module
(PCM) Outputs. The sensors and switches that pro-
vide inputs to the PCM are considered Powertrain
Control Module (PCM) Inputs.

The PCM adjusts ignition timing based upon

inputs it receives from sensors that react to: engine
rpm, manifold absolute pressure, engine coolant tem-
perature, throttle position, transmission gear selec-
tion (automatic transmission), vehicle speed and the
brake switch.

The PCM adjusts idle speed based on inputs it

receives from sensors that react to: throttle position,
vehicle speed, transmission gear selection, engine
coolant temperature and from inputs it receives from
the air conditioning clutch switch and brake switch.

Based on inputs that it receives, the PCM adjusts

ignition coil dwell. The PCM also adjusts the gener-
ator charge rate through control of the generator
field and provides speed control operation.

NOTE: PCM Inputs:

• A/C request (if equipped with factory A/C)

• A/C select (if equipped with factory A/C)

• Auto shutdown (ASD) sense

• Battery temperature

• Battery voltage

• Brake switch

• CCD bus (+) circuits

• CCD bus (-) circuits

• Camshaft position sensor signal

• Crankshaft position sensor

• Data link connection for DRB scan tool

• Engine coolant temperature sensor

• Fuel level

• Generator (battery voltage) output

• Ignition circuit sense (ignition switch in on/off/

crank/run position)

• Intake manifold air temperature sensor

• Leak detection pump (switch) sense (if equipped)

• Manifold absolute pressure (MAP) sensor

• Oil pressure

• Output shaft speed sensor

• Overdrive/override switch

• Oxygen sensors

• Park/neutral switch (auto. trans. only)

• Power ground

• Sensor return

• Signal ground

• Speed control multiplexed single wire input

• Throttle position sensor

• Transmission governor pressure sensor

• Transmission temperature sensor

• Vehicle speed inputs from ABS or RWAL system

NOTE: PCM Outputs:

• A/C clutch relay

• Auto shutdown (ASD) relay

• CCD bus (+/-) circuits for: speedometer, voltme-

ter, fuel gauge, oil pressure gauge/lamp, engine temp.
gauge and speed control warn. lamp

• Data link connection for DRB scan tool

• EGR valve control solenoid (if equipped)

• EVAP canister purge solenoid

• Five volt sensor supply (primary)

• Five volt sensor supply (secondary)

• Fuel injectors

• Fuel pump relay

• Generator field driver (-)

• Generator field driver (+)

• Generator lamp (if equipped)

• Idle air control (IAC) motor

• Ignition coil

• Leak detection pump (if equipped)

• Malfunction indicator lamp (Check engine lamp).

Driven through CCD circuits.

• Overdrive indicator lamp (if equipped)

• Radiator cooling fan (2.5L engine only)

• Speed control vacuum solenoid

• Speed control vent solenoid

• Tachometer (if equipped). Driven through CCD

circuits.

• Transmission convertor clutch circuit

• Transmission 3–4 shift solenoid

• Transmission relay

• Transmission temperature lamp (if equipped)

• Transmission variable force solenoid

OPERATION - 5 VOLT SUPPLIES

Primary 5–volt supply:
• supplies the required 5 volt power source to the

Crankshaft Position (CKP) sensor.

• supplies the required 5 volt power source to the

Camshaft Position (CMP) sensor.

• supplies a reference voltage for the Manifold

Absolute Pressure (MAP) sensor.

• supplies a reference voltage for the Throttle

Position Sensor (TPS) sensor.

Secondary 5–volt supply:
• supplies the required 5 volt power source to the

oil pressure sensor.

• supplies the required 5 volt power source for the

Vehicle Speed Sensor (VSS) (if equipped).

• supplies the 5 volt power source to the transmis-

sion pressure sensor (if equipped with an RE auto-
matic transmission).

8E - 14

ELECTRONIC CONTROL MODULES

POWERTRAIN CONTROL MODULE (Continued)

OPERATION - IGNITION CIRCUIT SENSE

The ignition circuit sense input tells the PCM the

ignition switch has energized the ignition circuit.

Battery voltage is also supplied to the PCM

through the ignition switch when the ignition is in
the RUN or START position. This is referred to as
the

9ignition sense9 circuit and is used to 9wake up9

the PCM. Voltage on the ignition input can be as low
as 6 volts and the PCM will still function. Voltage is
supplied to this circuit to power the PCM’s 8-volt reg-
ulator and to allow the PCM to perform fuel, ignition
and emissions control functions.

REMOVAL

USE THE DRB SCAN TOOL TO REPROGRAM

THE NEW POWERTRAIN CONTROL MODULE
(PCM) WITH THE VEHICLES ORIGINAL IDEN-
TIFICATION NUMBER (VIN) AND THE VEHI-
CLES ORIGINAL MILEAGE. IF THIS STEP IS
NOT DONE, A DIAGNOSTIC TROUBLE CODE
(DTC) MAY BE SET.

The PCM is located in the engine compartment

(Fig. 9).

To avoid possible voltage spike damage to the

PCM, ignition key must be off, and negative battery
cable must be disconnected before unplugging PCM
connectors.

(1) Disconnect negative battery cable at battery.
(2) Remove cover over electrical connectors. Cover

snaps onto PCM.

(3) Carefully unplug the three 32–way connectors

from PCM.

(4) Remove three PCM mounting bolts and remove

PCM from vehicle.

INSTALLATION

USE THE DRB SCAN TOOL TO REPROGRAM

(1) Install PCM and mounting bolts to vehicle.
(2) Tighten bolts to 3–5 N·m (30–40 in. lbs.).
(3) Check pin connectors in the PCM and the three

32–way connectors for corrosion or damage. Repair
as necessary.

(4) Install three 32–way connectors.
(5) Install cover over electrical connectors. Cover

snaps onto PCM.

(6) Install battery cable.
(7) Use the DRB scan tool to reprogram new PCM

with vehicles original Identification Number (VIN)
and original vehicle mileage. If this step is not done,
a Diagnostic Trouble Code (DTC) may be set.

SENTRY KEY IMMOBILIZER
MODULE

DESCRIPTION

The Sentry Key Immobilizer Module (SKIM) is the

primary component of the Sentry Key Immobilizer
System (SKIS) (Fig. 10). The SKIM is located on the
right side of the steering column, near the ignition
lock cylinder housing and is concealed beneath the
steering column shrouds. The molded black plastic
housing for the SKIM has an integral molded plastic
halo-like antenna ring that extends from one side.
When the SKIM is properly installed on the steering
column, the antenna ring is oriented around the cir-
cumference of the ignition lock cylinder housing. A
single integral connector receptacle containing six
terminal pins is located on the opposite end of the
SKIM housing from the antenna ring. A molded plas-
tic mounting tab that is integral to the SKIM hous-
ing has a hole in the center through which a screw
passes to secure the unit to the steering column. The

Fig. 9 PCM Location and Mounting

1 - RIGHT FRONT FENDER
2 - PCM MOUNTING BOLTS (3)
3 - 32–WAY CONNECTORS (3)
4 - COVER
5 - POWERTRAIN CONTROL MODULE (PCM)

ELECTRONIC CONTROL MODULES

8E - 15

POWERTRAIN CONTROL MODULE (Continued)

SKIM is connected to the vehicle electrical system
through a single take out and connector of the
instrument panel wire harness.

The SKIM cannot be adjusted or repaired. If faulty

or damaged, the entire SKIM unit must be replaced.

OPERATION

The Sentry Key Immobilizer Module (SKIM) con-

tains a Radio Frequency (RF) transceiver and a
microprocessor. The SKIM transmits RF signals to,
and receives RF signals from the Sentry Key tran-
sponder through a tuned antenna enclosed within the
molded plastic antenna ring integral to the SKIM
housing. If this antenna ring is not mounted properly
around the ignition lock cylinder housing, communi-
cation problems between the SKIM and the transpon-
der may arise. These communication problems will
result in Sentry Key transponder-related faults. The
SKIM also communicates over the Programmable
Communications Interface (PCI) data bus with the
Powertrain

Control

Module

(PCM),

the

Central

Timer Module (CTM), and/or the DRBIII

t scan tool.

The SKIM retains in memory the ID numbers of

any Sentry Key transponder that is programmed into
it. A maximum of eight Sentry Key transponders can
be programmed into the SKIM. For added system
security, each SKIM is programmed with a unique
Secret Key code. This code is stored in memory, sent
over the PCI data bus to the PCM, and is encoded to
the transponder of every Sentry Key that is pro-
grammed into the SKIM. Therefore, the Secret Key
code is a common element that is found in every com-
ponent of the Sentry Key Immobilizer System (SKIS).
Another security code, called a PIN, is used to gain

access to the SKIM Secured Access Mode. The
Secured Access Mode is required during service to
perform the SKIS initialization and Sentry Key tran-
sponder programming procedures. The SKIM also
stores the Vehicle Identification Number (VIN) in its
memory, which it learns through a PCI data bus
message from the PCM during SKIS initialization.

In the event that a SKIM replacement is required,

the Secret Key code can be transferred to the new
SKIM from the PCM using the DRBIII

t scan tool

and the SKIS initialization procedure. Proper com-
pletion of the SKIS initialization will allow the exist-
ing Sentry Keys to be programmed into the new
SKIM so that new keys will not be required. In the
event that the original Secret Key code cannot be
recovered, SKIM replacement will also require new
Sentry Keys. The DRBIII

t scan tool will alert the

technician during the SKIS initialization procedure if
new Sentry Keys are required.

When the ignition switch is turned to the On posi-

tion, the SKIM transmits an RF signal to the tran-
sponder in the ignition key. The SKIM then waits for
an RF signal response from the transponder. If the
response received identifies the key as valid, the
SKIM sends a valid key message to the PCM over
the PCI data bus. If the response received identifies
the key as invalid, or if no response is received from
the key transponder, the SKIM sends an invalid key
message to the PCM. The PCM will enable or disable
engine operation based upon the status of the SKIM
messages. It is important to note that the default
condition in the PCM is an invalid key; therefore, if
no message is received from the SKIM by the PCM,
the engine will be disabled and the vehicle immobi-
lized after two seconds of running.

The SKIM also sends security indicator status

messages to the CTM over the PCI data bus to tell
the CTM how to operate the security indicator. The
CTM then controls the security indicator in the Elec-
troMechanical Instrument Cluster (EMIC) through a
hard wired security indicator driver circuit. The secu-
rity indicator status message from the SKIM tells the
CTM to turn the indicator on for about three seconds
each time the ignition switch is turned to the On
position as a bulb test. After completion of the bulb
test, the SKIM sends security indicator status mes-
sages to the CTM to turn the indicator off, turn the
indicator on, or to flash the indicator on and off. If
the security indicator flashes or stays on solid after
the bulb test, it signifies a SKIS fault. If the SKIM
detects a system malfunction and/or the SKIS has
become inoperative, the security indicator will stay
on solid. If the SKIM detects an invalid key or if a
key transponder-related fault exists, the security
indicator will flash. If the vehicle is equipped with
the Customer Learn transponder programming fea-

Fig. 10 Sentry Key Immobilizer Module

1 - SENTRY KEY IMMOBILIZER MODULE
2 - IGNITION LOCK CYLINDER HOUSING
3 - SCREW
4 - INSTRUMENT PANEL WIRE HARNESS CONNECTOR

8E - 16

ELECTRONIC CONTROL MODULES

SENTRY KEY IMMOBILIZER MODULE (Continued)

ture, the SKIM will also send messages to the CTM
to flash the security indicator whenever the Cus-
tomer Learn programming mode is being utilized.
(Refer to 8 - ELECTRICAL/VEHICLE THEFT SECU-
RITY - STANDARD PROCEDURE - SENTRY KEY
TRANSPONDER PROGRAMMING).

The SKIS performs a self-test each time the igni-

tion switch is turned to the On position, and will
store fault information in the form of Diagnostic
Trouble Codes (DTC’s) in SKIM memory if a system
malfunction is detected. The SKIM can be diagnosed,
and any stored DTC’s can be retrieved using a
DRBIII

t scan tool. Refer to the appropriate diagnos-

tic information.

REMOVAL

(1) Disconnect and isolate the battery negative

cable.

(2) Remove the steering column opening cover

from the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - REMOVAL).

(3) If the vehicle is so equipped, grasp the tilt

steering column knob firmly and pull it straight rear-
ward to remove it from the tilt steering column
adjuster mechanism lever located on the left side of
the column just below the multi-function switch con-
trol stalk.

(4) From below the steering column, remove the

two outboard screws that secure the upper shroud to
the lower shroud.

(5) Push gently inward on both sides of the upper

shroud near the parting line between the upper and
lower shrouds to release the snap features that
secure it to the lower shroud.

(6) Remove the upper shroud from the lower

shroud.

(7) From below the steering column, remove the

one center screw that secures the lower shroud to the
steering column lock housing.

(8) Remove the lower shroud from the steering col-

umn.

(9) Disconnect the instrument panel wire harness

connector for the Sentry Key Immobilizer Module
(SKIM) from the SKIM connector receptacle (Fig. 11).

(10) Remove the screw that secures the SKIM to

the steering column lock housing.

(11) Disengage

the

SKIM

antenna

ring

from

around the ignition lock cylinder housing.

INSTALLATION

(1) Position the Sentry Key Immobilizer Module

(SKIM) onto the steering column with the antenna
ring oriented around the ignition lock cylinder hous-
ing (Fig. 11).

(2) Install and tighten the screw that secures the

SKIM to the steering column lock housing. Tighten
the screw to 2 N·m (20 in. lbs.).

(3) Reconnect the instrument panel wire harness

connector for the SKIM to the SKIM connector recep-
tacle.

(4) Position the lower shroud onto the steering col-

umn.

(5) From below the steering column, install and

tighten the one center screw that secures the lower
shroud to the steering column lock housing. Tighten
the screw to 2 N·m (20 in. lbs.).

(6) Position the upper shroud onto the steering col-

umn. If the vehicle is equipped with an automatic
transmission, be certain to engage the gearshift lever
gap hider into the openings in the right side of the
upper and lower shrouds.

(7) Align the snap features on the upper shroud

with the receptacles on the lower shroud and apply
hand pressure to snap them together.

(8) From below the steering column, install and

tighten the two screws that secure the upper shroud
to the lower shroud. Tighten the screws to 2 N·m (20
in. lbs.).

(9) If the vehicle is so equipped, align the tilt

steering column knob with the tilt steering column
adjuster mechanism lever located on the left side of
the column just below the multi-function switch con-
trol stalk and using hand pressure push the knob
firmly onto the lever.

(10) Reinstall the steering column opening cover

onto the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - INSTALLATION).

(11) Reconnect the battery negative cable.

Fig. 11 Sentry Key Immobilizer Module

1 - SENTRY KEY IMMOBILIZER MODULE
2 - IGNITION LOCK CYLINDER HOUSING
3 - SCREW
4 - INSTRUMENT PANEL WIRE HARNESS CONNECTOR

ELECTRONIC CONTROL MODULES

8E - 17

SENTRY KEY IMMOBILIZER MODULE (Continued)

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