GM Service Manual Online
For 1990-2009 cars only

The content theft deterrent (CTD) system, when armed, is designed to deter vehicle content theft by pulsing the horns and exterior lamps for approximately 2 minutes when an unauthorized vehicle entry is detected. However, the CTD system does not affect engine starting. The CTD system is armed and disarmed solely by the keyless entry transmitter. Once armed, if a keyless entry transmitter is not used to disarm the CTD system, an unauthorized entry will be detected.

An unauthorized entry can be any of the following with the CTD system armed:

    • When any door is opened without being unlocked by using the keyless entry transmitter.
    • When opening a door with the correct key without disarming the CTD system.

The components of the system are:

    • The body control module
    • The door ajar switches

Arming the CTD System

Important: The content theft deterrent (CTD) system can be armed with the windows or sunroof open.

Use the following procedure in order to arm the system:

  1. Place the shift lever in PARK (P).
  2. Turn OFF the ignition.
  3. Open any door.
  4. Important: The system is not armed if the doors are locked manually, the remote keyless entry transmitter must be used to arm the CTD system.

  5. Press the LOCK button on the transmitter. The horn will chirp 6 times to notify the operator that a door is open. A second press of the LOCK button within 3 seconds will lock the doors and the CTD system will arm as soon as the open door is closed.
  6. Alternately, the system can be armed after all doors are closed by simply pressing the LOCK button on the keyless entry transmitter. The system will arm as soon as the button is pressed.

Locking The Vehicle Without Arming The CTD System

Locking the vehicle may be accomplished without arming the content theft deterrent (CTD) system. Use of the manual door locks, power door lock switch, or by using the vehicle key to lock the doors will lock the vehicle but not arm the CTD system.

Disarming an Armed System/Silencing an Alarm

If system arming has been requested by the keyless entry transmitter, it must be disarmed. If the content theft deterrent (CTD) system has not been disarmed using the keyless entry transmitter and the vehicle is entered, the operator has 10 seconds to either start the vehicle or disarm the CTD system with the transmitter before the alarm is activated. However, this will be recognized as an unauthorized entry by the body control module (BCM) and upon the next CTD disarm cycle, the horn will chirp 3 times to notify the operator of an unauthorized entry.

Important: Using the power door unlock switch or manually unlocking the doors does not disable the CTD armed mode. Also, disconnecting the battery or pulling fuses does not disable the armed mode, since the BCM stores the CTD mode status in memory.

    • To disarm the CTD system in the armed mode:
       - Press the UNLOCK button on the keyless entry transmitter.
       - Insert a valid key into the ignition and start the vehicle.
    • To disarm the CTD system when activated, alarming mode.
       - Press the UNLOCK button on the keyless entry transmitter.
       - Insert a valid key into the ignition and start the vehicle.

CTD Circuit Description

The following is a description of each component used in the content theft deterrent (CTD) system:

Body Control Module (BCM)

The CTD system is an internal function of the body control module (BCM) which utilizes class 2 serial data and various switch input information to perform CTD functions. When the BCM detects an unauthorized entry, it activates the horns and exterior lamps.

If the BCM detects an unauthorized entry, the alarm mode will be entered. The BCM activates the horns and exterior lamps for 2 minutes. This is followed by a 3 minute time-out. If no new intrusions are detected after the time-out, the system resets. The system must be disarmed or the intrusion condition removed after the time-out for the system to exit alarm mode.

Door Ajar Switches

The content theft deterrent (CTD) system uses the door ajar switches in the door jambs as a method to activate the alarm. The body control module (BCM) monitors all door ajar switches via a discrete input from each door ajar switch. If the BCM receives a ground signal from a door ajar switch when the CTD system is armed, the BCM activates the alarm.

Inputs

The body control module (BCM) monitors the following inputs:

    • The driver and passenger door ajar switches
    • The transmitter LOCK/UNLOCK buttons, internal function of the BCM
    • The Passlock Status--The BCM uses the Passlock status for disarming the system or silencing and alarm when the correct key is used to start the vehicle.

Outputs

The body control module (BCM) controls the following:

    • The horn relay
    • The exterior lights