tion code from the transponder, and the transponder
learns the “Secret Key” code from the SKIM. Each of
these codes is stored within the transponder and in
the nonvolatile memory of the SKIM. Therefore,
blank keys for the SKIS must be programmed by and
into the SKIM, in addition to being cut to match the
mechanical coding of the ignition lock cylinder. See
Sentry Key Immobilizer System Transponder Pro-
gramming in this section for more information.
The Sentry Key transponder is within the range of
the SKIM transceiver antenna ring when it is
inserted in the ignition lock cylinder. When the igni-
tion switch is turned to the START or ON positions,
the SKIM transceiver issues a Radio Frequency (RF)
signal that excites the transponder chip. The tran-
sponder chip responds by issuing an RF signal con-
taining its transponder identification code and the
“Secret Key” code. The SKIM transceiver compares
the transponder codes with the codes stored in its
memory to determine whether a valid key is in the
ignition lock cylinder.
The Sentry Key transponder cannot be repaired
and, if faulty or damaged, it must be replaced.
TRIGGERING THE VTSS
Using the power door switch or the keyless trans-
mitter will arm the system. Any of the following
actions will trigger the system:
(1) Opening any door.
(2) Removing the deck lid lock cylinder.
(3) Turning the ignition to the ON position.
CAUTION: The VTSS indicator LED will trigger and
engine will continue to run if the vehicle is
equipped with SKIS and the proper key is used to
start the vehicle. This condition will occur if the
VTSS has been triggered.
NOTE: The ignition switch can be turned to the
accessory position without triggering alarm system.
DIAGNOSIS AND TESTING
SENTRY KEY IMMOBILIZER SYSTEM (SKIS)
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS,
REFER
TO
GROUP
8M
-
PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING
WHEEL,
STEERING
COLUMN,
OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
NOTE: The following tests may not prove conclu-
sive in the diagnosis of this system. The most reli-
able, efficient, and accurate means to diagnose the
Sentry Key Immobilizer System involves the use of
a DRB scan tool. Refer to the proper Body Diagnos-
tic Procedures manual for the procedures.
The Sentry Key Immobilizer System (SKIS) and
the Programmable Communication Interface (PCI)
bus network should be diagnosed using a DRB scan
tool. The DRB will allow confirmation that the PCI
bus is functional, that the Sentry Key Immobilizer
Module (SKIM) is placing the proper messages on the
PCI bus, and that the Powertrain Control Module
(PCM) is receiving the PCI bus messages. Refer to
the proper Body Diagnostic Procedures manual for
the procedures, and Group 8W, Wiring Diagrams for
complete circuit descriptions and diagrams.
(1) Check the fuses in the junction block. If OK, go
to Step 2. If not OK, repair the shorted circuit or
component as required and replace the faulty fuse.
(2) Disconnect and isolate the battery negative
remote cable from the remote terminal. Unplug the
wire harness connector at the SKIM. Check for con-
tinuity between the ground circuit cavity of the
SKIM wire harness connector and a good ground.
There should be continuity. If OK, go to Step 3. If not
OK, repair the open circuit to ground as required.
(3) Connect the battery negative remote cable.
Check for battery voltage at the fused B(+) circuit
cavity of the SKIM wire harness connector. If OK, go
to Step 4. If not OK, repair the open circuit to the
fuse in the junction block as required.
(4) Turn the ignition switch to the ON position.
Check for battery voltage at the fused ignition switch
output (run/start) circuit cavity of the SKIM wire
harness connector. If OK, use a DRB scan tool and
the proper Body Diagnostic Procedures manual to
complete the diagnosis of the SKIS. If not OK, repair
the open circuit to the fuse in the junction block as
required.
SERVICE PROCEDURES
SENTRY KEY IMMOBILIZER TRANSPONDER
PROGRAMMING
Two programmed Sentry Key transponders are
included with the Sentry Key Immobilizer System
(SKIS) when it is shipped from the factory. The Sen-
try Key Immobilizer Module (SKIM) can be pro-
grammed
to
recognize
up
to
six
additional
transponders, for a total of eight Sentry Keys. The
following “Customer Learn” programming procedure
for the programming of additional transponders
requires access to at least two of the valid Sentry
Keys. If two valid Sentry Keys are not available, Sen-
8Q - 4
VEHICLE THEFT/SECURITY SYSTEM
300M
DESCRIPTION AND OPERATION (Continued)