Dodge Ram Truck 1500-2500-3500. Manual - part 314

1. Install PCM (3) and 3 mounting bolts (4) to vehicle.

2. Tighten bolts. Refer to torque specifications.

3. Check pin connectors in the PCM and the three

32–way connectors (four 38–way connectors if
equipped with NGC) for corrosion or damage. Also,
the pin heights in connectors should all be same.
Repair as necessary before installing connectors.

4. Install three 32–way connectors (four 38–way con-

nectors if equipped with NGC).

5. Install cover over electrical connectors. Cover

snaps onto PCM.

6. Install negative battery cable.

7. The 5.7L V-8 engine is equipped with a fully

electronic accelerator pedal position sensor. If
equipped with a 5.7L, also perform the follow-
ing 3 steps:

a. Connect negative battery cable to battery.

b. Turn ignition switch ON, but do not crank

engine.

c. Leave ignition switch ON for a minimum of 10 seconds. This will allow PCM to learn electrical parameters.

d. The DRB III

Scan Tool may also be used to learn electrical parameters. Go to the Miscellaneous menu, and

then select ETC Learn.

8. If the previous step is not performed, a Diagnostic Trouble Code (DTC) will be set.

9. If necessary, use DRB III

Scan Tool to erase any Diagnostic Trouble Codes (DTC’s) from PCM. Also use the

DRB scan tool to reprogram new PCM with vehicles original Vehicle Identification Number (VIN) and original
vehicle mileage.

MODULE-SENTRY KEY IMMOBILIZER

DESCRIPTION

The Sentry Key Immobilizer Module (SKIM) (1) is the
primary component of the Sentry Key Immobilizer Sys-
tem (SKIS). This module contains a Radio Frequency
(RF) transceiver and a central processing unit, which
includes the Sentry Key Immobilizer System (SKIS)
program logic. 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 (4) that extends from the bottom. When the SKIM
is properly installed on the steering column, the
antenna ring is oriented around the circumference of
the ignition lock cylinder housing.

A single integral connector receptacle (3) is located
just behind the antenna ring on the bottom of the
SKIM housing. An integral molded plastic mounting
tab (2) on the rear corner of the SKIM housing has a
hole in the center through which a screw passes to
secure the unit to the steering column. The SKIM is

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

OPERATION

The Sentry Key Immobilizer Module (SKIM) transmits Radio Frequency (RF) signals to, and receives RF signals
from the Sentry Key transponder through a tuned antenna enclosed within the molded plastic antenna ring. If this
antenna ring is not mounted properly around the ignition lock cylinder housing, communication problems between
the SKIM and the transponder 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) for gasoline engines or the Engine Control Module (ECM) for diesel engines,
the ElectroMechanical Instrument Cluster (EMIC) and/or a diagnostic scan tool.

The SKIM and the PCM/ECM both use software that includes a rolling code algorithm strategy, which helps to
reduce the possibility of unauthorized Sentry Key Immobilizer System (SKIS) disarming. The rolling code algorithm
ensures security by preventing an override of the SKIS through the unauthorized substitution of the SKIM or the
PCM/ECM. However, the use of this strategy also means that replacement of either the SKIM or the PCM/ECM
units will require a system initialization procedure to restore system operation.

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
or ECM, and is encoded to the transponder of every Sentry Key that is programmed into the SKIM. Therefore, the
Secret Key code is a common element that is found in every component of the 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 transponder programming proce-
dures. The SKIM also stores the Vehicle Identification Number (VIN) in its memory, which it learns through a PCI
data bus message from the PCM or ECM 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 a diagnostic scan tool and the SKIS initialization procedure. Proper completion of the SKIS initialization
will allow the existing 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 diagnostic 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 or Start positions, the SKIM transmits an RF signal to excite the tran-
sponder in the ignition key. The SKIM then listens for a return RF signal from the transponder. If the SKIM receives
an RF signal with a valid “Secret Key” and transponder identification codes, the SKIM sends a “valid key” message
to the PCM/ECM over the PCI bus. If the SKIM receives an invalid RF signal or no response, it sends “invalid key”
messages to the PCM/ECM. The PCM/ECM 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 or ECM is an invalid key. Therefore,
if no message is received from the SKIM by the PCM or ECM, the engine will be disabled and the vehicle immo-
bilized after two seconds of running.

The SKIM also sends electronic messages to the EMIC which control the VTSS indicator. The SKIM sends mes-
sages to the EMIC to turn the indicator on for about three seconds when the ignition switch is turned to the On
position as a bulb test. After completion of the bulb 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 bulb test, it indicates that the
SKIM has detected a system malfunction and/or that the SKIS has become inoperative.

If the SKIM detects an invalid key when the ignition 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 and to generate a single audible chime
whenever the Customer Learn programming mode is being utilized. (Refer to 8 - ELECTRICAL/VEHICLE THEFT
SECURITY - STANDARD PROCEDURE - SENTRY KEY TRANSPONDER PROGRAMMING).

The SKIS will store fault information in the form of Diagnostic Trouble Codes (DTC’s) in SKIM memory if a system
malfunction is detected. For diagnosis or initialization of the SKIM and the PCM/ECM, a diagnostic scan tool is
required. Refer to the appropriate diagnostic information.

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REMOVAL

WARNING: To avoid personal injury or death, on vehicles equipped with airbags, disable the supplemental
restraint system before attempting any steering wheel, steering column, airbag, seat belt tensioner, impact
sensor, or instrument panel component diagnosis or service. Disconnect and isolate the battery negative
(ground) cable, then wait two minutes for the system capacitor to discharge before performing further diag-
nosis 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.

1. Disconnect and isolate the battery negative cable.

2. Grasp the tilt steering column knob (2) firmly and

pull it straight rearward to remove it from the tilt
adjuster lever (1) on the left side of the column.

3. From below the steering column, remove the two

outboard screws that secure the upper column
shroud (1) to the lower shroud (3).

4. Using hand pressure, push inward on both sides of

the upper shroud above the parting line of the
lower shroud to release the snap features that
secure the two shroud halves to each other.

5. Remove the upper shroud from the lower shroud

and the steering column.

6. Remove the one center screw that secures the

lower shroud to the steering column (4).

7. Remove

the

lower

shroud

from

the

steering

column.

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8. Disconnect the wire harness connector (2) from the

Sentry Key Immobilizer Module (SKIM) (1).

9. Remove the screw (3) that secures the SKIM (1) to

the steering column (2).

10. Disengage the antenna ring from around the igni-

tion lock cylinder housing and remove the SKIM.

INSTALLATION

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