General Information; Arming; Disarming - Jeep 1997 Grand Cherokee Service Manual

8Q - 2 VEHICLE THEFT/SECURITY SYSTEMS
GENERAL INFORMATION (Continued)
item on the DRB scan tool for the procedures. Once
this condition has been met, the PCM will allow the
engine no-run feature to arm.
Once the VTSS engine no-run feature has been
enabled, it cannot be disabled unless the PCM is
replaced with a new unit. The same VTSS engine no-
run feature enable logic will apply anytime the PCM
is replaced with a new unit.
VEHICLE IMMOBILIZER SYSTEM
The vehicle immobilizer system is disabled when it
is shipped from the factory. This is done by program-
ming within the Powertrain Control Module (PCM)
and the Body Control Module (BCM). The logic in the
BCM allows the vehicle immobilizer system functions
to remain dormant in vehicles sold in countries
where it is not required. The logic in the PCM pre-
vents the immobilizer system from arming until the
engine start counter within the PCM sees twenty
engine starts. The vehicle immobilizer system must
be enabled when the vehicle is received from the
assembly plant, if this feature is required or desired.
The only method for setting up the BCM to allow
the immobilizer system to become functional is to use
a DRB scan tool. Refer to the Body Computer menu
item on the DRB scan tool for the procedures. The
preferred method for enabling the vehicle immobi-
lizer system is to electronically advance the PCM
engine start counter using a DRB scan tool. Refer to
the Vehicle Theft Security System menu item on the
DRB scan tool for the procedures. Once these condi-
tions have been met, the BCM and PCM will allow
the vehicle immobilizer system to function and arm.
Once the vehicle immobilizer system has been
enabled, it cannot be disabled unless the PCM and
the BCM are replaced with new units. The same
vehicle immobilizer system enable logic will apply
anytime the PCM and/or the BCM are replaced with
new units.

ARMING

VEHICLE THEFT SECURITY SYSTEM
Passive arming of the VTSS occurs when the vehi-
cle is exited with the key removed from the ignition
switch, the headlamps are turned off, and the doors
are locked using the power lock switch. The power
lock switch will not function if the key is in the igni-
tion switch or the headlamps are on with the driver
side front door open. The VTSS will not arm if either
front door or the liftgate are locked using the key in
the lock cylinder.
Active arming of the VTSS occurs when the
Remote Keyless Entry (RKE) transmitter is used to
lock the vehicle, even if the doors and/or the liftgate
are open when the RKE transmitter Lock button is
depressed. However, the VTSS arming will not be
complete until all the doors and the liftgate are
closed.
Following successful passive or active VTSS arm-
ing, the VTSS set lamp on the top of the instrument
panel will flash rapidly for about fifteen seconds after
the illuminated entry system times out. This indi-
cates that VTSS arming is in progress. Once the fif-
teen second arming function is complete, the set
lamp will flash at a slower rate to indicate that the
VTSS is armed.
VEHICLE IMMOBILIZER SYSTEM
Active arming of the vehicle immobilizer system
occurs when the vehicle is locked using the power
lock switch or when the Lock button of the Remote
Keyless Entry (RKE) transmitter is used to lock the
vehicle. Arming will occur, even if the doors and/or
the liftgate are open when the vehicle is locked, as
long as the ignition switch is in the Off position. The
vehicle immobilizer system cannot be actively armed
while the ignition switch is in the On or Start posi-
tions.
Passive arming of the system occurs when the igni-
tion switch is in the Off position for more than five
minutes (one minute for vehicles sold in the United
Kingdom). See Power-Up Mode in this group for a
description of other conditions that can result in pas-
sive arming of the vehicle immobilizer system.
Following receipt of a passive or active request for
arming of the vehicle immobilizer system, a set lamp
located on top of the instrument panel will begin to
flash rapidly for fifteen seconds. Following successful
vehicle immobilizer system arming (about fifteen sec-
onds), the set lamp will continue to flash, but at a
much slower rate. The slow flashing of the set lamp
will continue for as long as the vehicle immobilizer
system is armed.

DISARMING

VEHICLE THEFT SECURITY SYSTEM
Passive disarming of the VTSS occurs when the
vehicle is unlocked using the key to unlock either
front door or the liftgate. Active disarming of the
VTSS occurs when the vehicle is unlocked by
depressing the Unlock button of the Remote Keyless
Entry (RKE) transmitter.
Once the alarm has been activated (horn sounding,
lights flashing, and the engine no-run feature), either
disarming method will also deactivate the alarm.
Depressing the Panic button on the RKE transmit-
ter will also disarm the VTSS, but the horn will
sound and the lights will flash for about three min-
utes as part of the Panic feature. Refer to Group 8P -
Power Lock Systems for more information on the
Panic feature.
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