Jeep 1997 Grand Cherokee Service Manual page 564

8Q - 4 VEHICLE THEFT/SECURITY SYSTEMS
DESCRIPTION AND OPERATION (Continued)
tion switch to the OFF position and using one of the
following methods.
(1) Press the LOCK button on the RKE transmit-
ter.
(2) LOCK the doors by pressing a power lock but-
ton switch.
(3) LOCK the driver or passenger door using the
key.
• The Security light will flash, for about 16 sec-
onds, indicating that the engine will be disabled.
• The Security light remaining on, indicates the
system is not operational.
• The Immobilizer will activate automatically
within 10 minutes of the ignition switch being in the
OFF position, whether the vehicle has been locked or
unlocked.
• An attempt to start the vehicle without pressing
the UNLOCK button on the RKE transmitter will
result in a warning chime and the Security light
flashing.
NOTE: The ignition switch must be in the OFF posi-
tion in order for the system to be activated, whether
the doors are closed or not.
IMMOBILIZER RECEIVER
The immobilizer
respond to the Lock and Unlock radio signals issued
by the immobilizer transmitters. The receiver will
only respond to the radio signals of transmitters (up
to four) whose vehicle access codes have been stored
in the receiver's electronic memory. The receiver is
programmed at the assembly plant with the vehicle
access codes of the two transmitters that are shipped
with the vehicle.
The immobilizer receiver also has a central pro-
cessing unit, which contains the immobilizer system
logic. The programming in the immobilizer receiver
allows the system to learn and retain transmitter
vehicle access codes, as well as to communicate with
the Powertrain Control Module (PCM) and/or the
DRB scan tool on the Chrysler Collision Detection
(CCD) data bus network.
The CCD data bus network allows the sharing of
sensor information. This helps to reduce wiring har-
ness complexity, reduce internal controller hardware,
and reduce component sensor current loads. At the
same time, the CCD data bus network provides
increased reliability and enhanced diagnostic capabil-
ities.
Each immobilizer transmitter has a different vehi-
cle access code, which must be programmed into the
memory of the immobilizer receiver in the vehicle in
order to operate the immobilizer system. A DRB scan
tool must be used to program new or additional
transmitter vehicle access codes into the memory of
receiver is programmed
the immobilizer receiver. Refer to the Vehicle Theft
Security System menu item on the DRB scan tool for
the procedures.
The immobilizer receiver recognizes the Lock and
Unlock signals received from the programmed immo-
bilizer transmitters. The receiver then uses the pro-
grammed immobilizer system logic to decide whether
other monitored conditions are proper for an engine
Lock or Unlock message to be sent. If the pro-
grammed conditions are met, the receiver responds
by sending the proper message to the PCM on the
CCD data bus. The PCM responds to the message by
disabling or enabling the fuel injector driver circuitry
within the PCM, which will inhibit engine operation.
The immobilizer receiver is mounted to the dash
panel with a hook and loop fastener patch. It is
located behind the instrument cluster and above the
driver side end of the heater-A/C housing. The
receiver is connected to the dash panel cross-body
wiring harness.
For diagnosis of the vehicle immobilizer receiver or
the CCD data bus, a DRB scan tool is required. Refer
to the Vehicle Theft Security System menu item of
the DRB scan tool for the procedures. The immobi-
lizer receiver cannot be repaired and, if faulty, the
unit must be replaced.
to
IMMOBILIZER TRANSMITTER
The vehicle immobilizer system includes two trans-
mitters that are supplied with the vehicle when it is
shipped from the factory. Each of the two transmit-
ters is equipped with two buttons labeled with Inter-
national Standards Organization (ISO) symbols for
Lock, and Unlock. Two spare batteries (enough for
one transmitter) are also shipped with the transmit-
ters. The transmitters are equipped with a key ring
and are designed to serve as a key fob. The operating
range of the radio frequency transmitter signal is up
to 7 meters (23 feet) from the immobilizer receiver.
Each transmitter has a different vehicle access
code, which must be programmed into the memory of
the immobilizer receiver in the vehicle in order to
operate the immobilizer system. The two transmit-
ters shipped with the vehicle have their vehicle
access codes programmed into the receiver at the fac-
tory. A DRB scan tool must be used to program new
or additional transmitter vehicle access codes into
the memory of the immobilizer receiver. Refer to the
Vehicle Theft Security System menu item on the
DRB scan tool for the procedures.
Each transmitter operates on two Duracell DL2016
(or equivalent) batteries. Typical battery life is from
one to two years.
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