The PATS is the anti theft part that can not be disabled. It is the part that disables the start and fuel if the vehicle does not sense the transponder in the key. The perimeter alarm is the part that sounds the horn and flashes the lights if the door is opened without using the remote.
DESCRIPTION AND OPERATION
Anti-Theft
The perimeter anti-theft alarm system consists of the following:
Door ajar input
Door lock control switch input
Hood switch
Horn
Integrated Keyhead Transmitter (IKT) key
Keyless entry keypad
Passive Anti-Theft System (PATS) key read
Turn signals
Body Control Module (BCM)
The perimeter alarm system protects the vehicle from unauthorized entry by
sounding the horn and flashing both the turn signals and courtesy lights when an
unauthorized entry occurs. The horn and lights are active for 30 seconds. After
30 seconds, the horn stops sounding, but the lights continue to flash for up to
5 minutes.
The perimeter alarm only activates 10 times per arming cycle. After that the
alarm does not activate. To enable the perimeter alarm again, disarm the
perimeter alarm and then arm it again.
Arming the Perimeter Alarm
The perimeter alarm is ready to arm any time the ignition is off. Any of the
following pre-arms the alarm system:
pressing the LOCK button on an IKT.
pressing the door lock control switch to the lock position with the door open,
then closing the door.
pressing the 7/8 and 9/0 buttons simultaneously on the keyless entry keypad.
Once the system is pre-armed, there is a 20-second countdown before the
perimeter alarm is armed. Each entry point to the vehicle (hood or door) are
armed separately and must be closed before that entry point begins the 20-second
countdown to become armed. If all entry points are closed, the turn signals
flash indicating that all entry points are entering the 20-second countdown.
Perimeter Alarm Activation
The perimeter alarm has a 12-second delay when the driver door is unlocked using
a key in the door lock cylinder and then opened. During the delay, a chime
sounds and "TO STOP ALARM START VEHICLE" is displayed in the message center. If
the perimeter alarm is not disarmed within the 12-second delay, the alarm is
activated.
The perimeter alarm is activated when:
any passenger door or the hood is opened without first receiving an electronic
unlock command from an IKT or keyless entry keypad.
the driver door is opened without first receiving an unlock command from an
IKT or keyless entry keypad and the 12-second delay has expired.
the ignition is turned to the RUN position without a valid PATS key read
received.
Disarming the Perimeter Alarm
The perimeter alarm can be disarmed by:
pressing the UNLOCK button on a programmed IKT.
using a programmed IKT to transition the ignition to the RUN position.
entering the correct vehicle unlock code on the keyless entry keypad.
The perimeter alarm can be deactivated by pressing the PANIC button on an IKT.
All of the lamps stop flashing and the horn stops sounding, but the alarm is
still armed.
Panic Alarm
The panic alarm operates similar to the perimeter alarm, but is only controlled
by the panic button on the IKT. Refer to HANDLES, LOCKS, LATCHES AND ENTRY
SYSTEMS for information on the panic alarm operation.
It looks like as long as you turn the key on within 12 seconds of opening the door it won't set off the alarm. I know when I have had to open my truck without the remote it starts to chirp until I get the key in it. The other technique that should work is to manually lock the door before you get out. Maybe hit the power door lock button before you shut the truck off then manually lock the driver door on your way out. It may be possible to turn off the perimeter with a programming tool.
