DESCRIPTION
The Sentry Key Immobilizer System (SKIS) is available as a factory-installed
option on this model. Vehicles equipped with this option can be readily
identified by the presence of an amber SKIS indicator in the instrument
cluster that will illuminate for about three seconds each time the ignition
switch is turned to the On position, or by a gray molded rubber cap on
the head of the ignition key. Models not equipped with SKIS still have
a SKIS indicator in the cluster, but it will not illuminate when the ignition
switch is turned to the On position. Also, models not equipped with
the SKIS have a black molded rubber cap on the head of the ignition key.
The SKIS includes the following major components, which are described
in further detail elsewhere in this service manual:
Powertrain Control Module (PCM) - The PCM is located on
the right side of the dash panel in the engine compartment.
Sentry Key Immobilizer Module (SKIM) - The SKIM is located on the
steering column near the ignition lock cylinder housing and an integral molded
plastic antenna ring circles the ignition lock cylinder like a halo. The SKIM
and its antenna are concealed beneath the steering column shrouds.
Sentry Key Transponder - The Sentry Key transponder is molded into the head
of the ignition key, and concealed by a gray molded rubber cap.
SKIS Indicator - The SKIS indicator is located in the upper left corner
of the instrument cluster overlay. Except for the Sentry Key transponders,
which rely upon Radio Frequency (RF) communication, hard wired circuitry
connects the SKIS components to the electrical system of the vehicle. These hard
wired circuits are integral to several wire harnesses, which are routed
throughout the vehicle and retained by many different methods. These circuits
may be connected to each other, to the vehicle electrical system and to the SKIS
components through the use of a combination of soldered splices, splice block
connectors, and many different types of wire harness terminal connectors and
insulators. Refer to the appropriate wiring information. The wiring information
includes wiring diagrams, proper wire and connector repair procedures, further
details on wire harness routing and retention, as well as pin-out and location
views for the various wire harness connectors, splices and grounds.
OPERATION
The Sentry Key Immobilizer System (SKIS) is designed to provide passive
protection against unauthorized vehicle use by disabling the engine, after about
two seconds of running, whenever any method other than a valid Sentry Key is
used to start the vehicle. The SKIS is considered a passive protection system
because it is always active when the ignition system is energized and does not
require any customer intervention. The SKIS uses Radio Frequency (RF)
communication to obtain confirmation that the key in the ignition switch is a
valid key for operating the vehicle. The microprocessor-based SKIS hardware and
software also uses electronic messages to communicate with other electronic
modules in the vehicle over the Programmable Communications Interface (PCI) data
bus
Pre-programmed Sentry Key transponders are provided with the
vehicle from the factory. Each Sentry Key Immobilizer Module (SKIM) will
recognize a maximum of eight Sentry Keys. If the customer would like additional
keys other than those provided with the vehicle, they may be purchased from any
authorized dealer. These additional keys must be programmed to the SKIM in the
vehicle in order for the system to recognize them as valid keys. This can be
done by the dealer using a DRBIII scan tool or, if Customer Learn programming is
an available SKIS feature in the market where the vehicle was purchased, the
customer can program the additional keys, as long as at least two valid Sentry
Keys are already available.
The SKIS performs a self-test each time the ignition switch is
turned to the On position, and will store fault information in the form of
Diagnostic Trouble Codes (DTC’s) if a system malfunction is detected. The SKIS
can be diagnosed, and any stored DTC’s can be retrieved using a DRBIII scan
tool. Refer to the appropriate diagnostic information.
STANDARD PROCEDURE - SENTRY KEY TRANSPONDER PROGRAMMING
All Sentry Keys included with the vehicle are preprogrammed to work with the
Sentry Key Immobilizer System (SKIS) when it is shipped from the factory. The
Sentry Key Immobilizer Module (SKIM) can be programmed to recognize up to a
total of eight Sentry Keys. When programming a blank Sentry Key
transponder, the key must first be cut to match the ignition switch lock
cylinder in the vehicle for which it will be used. Once the additional or new
key has been cut, the SKIM must be programmed to recognize it as a valid key.
There are two possible methods to program the SKIM to recognize a new or
additional valid key, the Secured Access Method and the Customer Learn Method.
Following are the details of these two programming methods.
SECURED ACCESS METHOD
The Secured Access method applies to all vehicles. This method requires the use
of a DRBIII scan tool. This method will also require that you have access to the
unique four-digit PIN code that was assigned to the original SKIM. The PIN code must be used to enter the Secured Access Mode in the SKIM. This PIN number may be
obtained from the vehicle owner, from the original vehicle invoice, or from the
DaimlerChrysler Customer Center. Refer to the appropriate diagnostic information
for the proper Secured Access method programming procedures.
CUSTOMER LEARN METHOD
The Customer Learn feature is only available on domestic vehicles, or those
vehicles which have a U.S. country code designator. This programming
method also requires access to at least two valid Sentry Keys. If two valid
Sentry Keys are not available, or if the vehicle does not have a U.S. country
code designator, the Secured Access Method must be used to program new or
additional valid keys to the SKIM.
The Customer Learn programming method procedures are as follows:
(1) Obtain the blank Sentry Key(s) that are to be programmed as valid keys for
the vehicle. Cut the blank key(s) to match the ignition switch lock cylinder
mechanical key codes.
(2) Insert one of the two valid Sentry Keys into the ignition switch and turn
the ignition switch to the On position.
(3) After the ignition switch has been in the On position for longer than three
seconds, but no more than fifteen seconds, cycle the ignition switch back to the
Off position. Replace the first valid Sentry Key in the ignition switch lock
cylinder with the second valid Sentry Key and turn the ignition switch back to
the On position. The second valid Sentry Key must be inserted in the lock
cylinder within fifteen seconds of removing the first valid key.
(4) About ten seconds after the completion of Step 3, the SKIS indicator in the
instrument cluster will start to flash and a single audible chime will sound to
indicate that the system has entered the Customer Learn programming mode.
(5) Within sixty seconds of entering the Customer Learn programming mode, turn
the ignition switch to the Off position, replace the valid Sentry Key with a
blank Sentry Key transponder, and turn the ignition switch back to the On
position.
(6) About ten seconds after the completion of Step 5, a single audible chime
will sound and the SKIS indicator will stop flashing, stay on solid for three
seconds, then turn off to indicate that the blank Sentry Key has been
successfully programmed. The SKIS will immediately exit the Customer Learn
programming mode and the vehicle may now be started using the newly programmed
valid Sentry Key. Each of these steps must be repeated and completed in
their entirety for each additional Sentry Key that is to be programmed. If the
above steps are not completed in the given sequence, or within the allotted
time, the SKIS will exit the Customer Learn programming mode and the programming
will be unsuccessful. The SKIS will also automatically exit the Customer Learn
programming mode if it sees a non-blank Sentry Key transponder when it should
see a blank, if it has already programmed eight (8) valid Sentry Keys, or if the
ignition switch is turned to the Off position for more than about fifty seconds.
NOTE: If an attempt is made to start the vehicle while in the
Customer Learn mode (SKIS indicator flashing), the SKIS will respond as though
the vehicle were being started with an invalid key. In other words, the engine
will stall after about two seconds of operation. No faults will be set.
NOTE: Once a Sentry Key has been programmed as a valid key to a
vehicle, it cannot be programmed as a valid key for use on any other vehicle.
