Jeep Cherokee 2000 Service Manual - page 530
VEHICLE THEFT/SECURITY SYSTEMS
TABLE OF CONTENTS
page
page
GENERAL INFORMATION
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SENTRY KEY IMMOBILIZER SYSTEM . . . . . . . . . 1
DESCRIPTION AND OPERATION
SENTRY KEY IMMOBILIZER MODULE. . . . . . . . . 1
SENTRY KEY IMMOBILIZER TRANSPONDER . . . 2
SENTRY KEY IMMOBILIZER SYSTEM
INDICATOR LAMP . . . . . . . . . . . . . . . . . . . . . . . 3
DIAGNOSIS AND TESTING
SENTRY KEY IMMOBILIZER SYSTEM . . . . . . . . . 3
SERVICE PROCEDURES
SENTRY KEY IMMOBILIZER SYSTEM
TRANSPONDER PROGRAMMING . . . . . . . . . . . 4
REMOVAL AND INSTALLATION
SENTRY KEY IMMOBILIZER MODULE. . . . . . . . . 4
GENERAL INFORMATION
INTRODUCTION
The Sentry Key Immobilizer System (SKIS) is
available factory-installed optional equipment for this
model. Following are some general descriptions of the
features and components of the SKIS. Refer to the
vehicle owner’s manual for more information on the
use and operation of the SKIS. Refer to 8W-30 - Fuel/
Ignition System in Group 8W - Wiring Diagrams for
complete circuit descriptions and diagrams.
SENTRY KEY IMMOBILIZER SYSTEM
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 SKIS indicator lamp, 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 SKIS indicator lamp is located in the
instrument cluster.
The SKIS includes two valid Sentry Key transponders
from the factory. 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 using the Customer Learn
programming procedure or a DRBIII
t
scan tool. 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 (DTCs) if a system
malfunction is detected. The SKIS can be diagnosed,
and any stored DTC can be retrieved using a
DRBIII
t
scan tool as described in the proper Diag-
nostic Procedures manual.
DESCRIPTION AND OPERATION
SENTRY KEY IMMOBILIZER MODULE
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 one, but no
more than eight electronically coded Sentry Key
transponders. The SKIS programming also enables
the SKIM to communicate over the Chrysler Collision
Detection (CCD) data bus network with the Power-
train Control Module (PCM), the instrument cluster
and/or the DRBIII
t
scan tool.
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 order
to ensure proper RF communication between the
SKIM and the Sentry Key transponder.
For added system security, each SKIM is pro-
grammed with a unique “Secret Key” code and a
security code (PIN). The SKIM keeps the “Secret
Key” code in memory. This “Secret Key” code must be
transferred to the PCM memory during the initializa-
tion/programming of the SKIS when the vehicle is
manufactured, and each time the PCM is replaced
during vehicle service by the dealer technician. The
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VEHICLE THEFT/SECURITY SYSTEMS
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