Chrysler PT Cruiser, Service & Repair Manual, Page: 330 / 2078

OPERATION
When the ignition switch is moved to the RUN
position, the SKIM transmits an RF signal to the
transponder in the ignition key. The SKIM then
waits for a response RF signal from the transponder
in the key. If the response received identifies the key
as valid, the SKIM sends a
9
valid key
9
message to
the PCM over the PCI bus. If the response received
identifies the key as invalid or no response is
received from the transponder in the ignition key, the
SKIM sends an
9
invalid key
9
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
9
invalid key.
9
Therefore, if no response is
received by the PCM, the engine will be immobilized
after two (2) seconds of running.
The SKIM also sends indicator light status mes-
sages to the instrument cluster to tell that module
how to operate the light. This may consist of turning
the light ON for a three (3) second bulb test when
the ignition switch is first turned to the ON position.
It is also the method used to turn the light ON solid
or to flash it after the indicator light test is complete
to signify a fault in the SKIS. If the light comes ON
and stays ON solid after the indicator light test, this
signifies that the SKIM has detected a system mal-
function and/or that the SKIS has become inopera-
tive. If the SKIM detects an invalid key OR a key-
related fault exists, the indicator light will flash
following the indicator light test. The SKIM may also
request an audible chime if the customer key pro-
gramming feature is available and the procedure is
being utilized. Refer to Electrical, Vehicle Theft Secu-
rity, Transponder Key, Standard Procedure - Sentry
Key Immobilizer System Transponder programming.
STANDARD PROCEDURE - SENTRY KEY
IMMOBILIZER SYSTEM INITIALIZATION
The Sentry Key Immobilizer System (SKIS) initial-
ization should be performed following a Sentry Key
Immobilizer Module (SKIM) replacement. It can be
summarized as follows:
(1) Obtain the vehicle’s unique four-digit PIN
assigned to its original SKIM from the vehicle owner,
the vehicle’s invoice, or from Chrysler’s Customer
Center.
(2) Using a DRB III
t
scan tool, select
9
Theft
Alarm,
9 9
SKIM,
9 9
Miscellaneous,
9
and then
9
SKIM
Module Replaced.
9
(a) Enter Secured Access Mode using the unique
four-digit PIN.
(b) Program the vehicle’s VIN number into the
SKIM’s memory.
(c) Program the country code into the SKIM’s
memory (for North America, choose US or domes-
tic).
(d) The vehicle’s unique Secret Key data will be
retrieved from the PCM automatically. If this data
is corrupt or not present, you will be prompted to
cut new keys for this vehicle.
(3) Program all customer keys into the SKIM’s
memory.
This process will require that the SKIM to be in
the Secured Access Mode. The PIN must be entered
into the DRB III
t
scan tool before the SKIM will
enter the Secured Access Mode. Once entered,
Secured Access Mode shall be active until 60 seconds
after the last command requiring secured access was
received and acknowledged.
Two exceptions to this rule are:
•
When you have used the ’erase all keys’ com-
mand OR
•
When you have just programmed a new key.
If either of these functions are performed success-
fully while in the Secured Access Mode, this mode
will be exited immediately following the function.
NOTE: If a PCM is replaced, the unique ’Secret Key’
data must be transferred from the SKIM to the new
PCM using the PCM replacement procedure. This
procedure requires the Secured Access Mode as
well and can be found in the DRB III
T
scan tool.
REMOVAL
(1) Disconnect and isolate the battery negative
remote cable.
(2) Remove Lower Instrument Panel Cover. Refer
to Body, Instrument Panel, Lower Instrument Panel
Cover, Removal.
(3) Remove the steering column upper and lower
shrouds. Refer to Steering, Column, Column Shroud,
Removal.
(4) Disengage the steering column wire harness
from the Sentry Key Immobilizer Module (SKIM)
(Fig. 25).
(5) Remove the two screws securing the SKIM to
the top of the steering column (Fig. 25).
(6) Rotate the SKIM and its mounting bracket
upwards and then to the side away from the steering
column to slide the SKIM antenna ring from around
the ignition switch lock cylinder housing (Fig. 25).
(7) Remove the SKIM from the vehicle.
8E - 16 ELECTRONIC CONTROL MODULES
PT
SENTRY KEY IMMOBILIZER MODULE (Continued)