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 30 seconds when an unauthorized vehicle entry is detected. However, the CTD System does not affect engine starting.

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

    • When the liftgate or liftglass has been opened without the use of the keyless entry system or without first being unlocked.
    • When any door is opened without first being unlocked using the keyless entry transmitter.
    • When the driver door is opened without being first unlocked using the driver door cylinder.

The components of the system are:

    • The body control module
    • The door ajar switches
    • The driver door key cylinder switch
    • The liftgate/liftglass ajar switch

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. Turn OFF the ignition.
  2. Exit the vehicle.
  3. Important: The system is not armed if the doors are locked manually. The keyless entry transmitter or the door lock switch must be used to arm the CTD system.

  4. With a vehicle door open, lock the doors by pressing the LOCK button on the keyless entry transmitter or by pressing the LOCK button on the door lock switch. The system will begin the arm sequence when all doors are closed. The CTD system transition to the arm delay state when the final door is closed. The security indicator will illuminate steady when in the arm delay state.
  5. If the keyless entry transmitter LOCK button is pressed after the vehicle doors have been closed, the system will transition directly to the arm delay state with the indicator on steady.

  6. The system will arm approximately 30 seconds from the time that the system has entered the arm delay state. When the security indicator transitions to flashing slowly, the system is armed.
  7. Alternately, if the LOCK button on the keyless entry transmitter is pressed a second time, the system will arm immediately, bypassing the 30 second delay.

Locking The Vehicle Without Arming The CTD System

Locking the vehicle may be accomplished without arming the content theft deterrent (CTD) system by locking the vehicle by using the manual door locks.

Disarming an Armed System/Silencing an Alarm

If system arming has occurred, it must be disarmed.

Important: Manually unlocking the doors does not disable the content theft deterrent (CTD) armed mode. Also, disconnecting the battery or pulling fuses does not disable the armed mode, as the BCM stores the CTD status in memory.

To disarm the CTD system perform one of the following:

    • Press the UNLOCK button on the keyless entry transmitter.
    • Unlock the driver door using the door key cylinder.
    • 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 serial data and various switch inputs to perform CTD functions. When the BCM detects an unauthorized entry, it activates the horns and exterior lamps for 30 seconds. Following the 30-second alarm period is a 10-second time-out. The system will then re-arm.

Door Ajar Switches

The CTD system uses the door ajar switches as a status indicator to activate the alarm. The BCM receives the status of the front door ajar switches based on serial data messages from the Driver Door Module (DDM) and Passenger Door Module (PDM). The rear door ajar switches are monitored 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.

Liftgate/Ligtglass Ajar Switch

The CTD system uses the liftgate and liftglass ajar switchs as a status indicator to activate the alarm. The liftgate/liftglass ajar switch is monitored via a discrete input from the switch. If the BCM receives a ground signal from the ajar switch when the CTD system is armed, the BCM activates the alarm.

Driver Door Cylinder Switch

The CTD system uses the driver door cylinder switch as a means to disarm the CTD system. When the driver door key cylinder is rotated, the driver door cylinder switch is closed. The driver door cylinder switch is monitored by the DDM. With the driver door cylinder switch closed, a ground signal is seen on the Driver Door Key Switch Signal circuit. The DDM will then send a serial data message to the BCM indicating that a valid key has been used to rotate the driver door cylinder and the CTD system should be disarmed.

Inputs

The BCM monitors the following inputs:

    • The door LOCK/UNLOCK switch; a serial data message from the DDM
    • The driver and passenger door ajar switches; both a serial data message from the DDM/PDM and a discrete input
    • The liftgate/liftglass ajar switch; a discrete input to the BCM
    • Driver door cylinder switch; a serial data message from the DDM
    • The keyless entry transmitter LOCK/UNLOCK buttons; a serial data message from the RCDLR
    • The immobilizer status--The BCM uses the immobilizer status for disarming the system or silencing and alarm when the correct vehicle key is used to start the vehicle

Outputs

The BCM controls the following:

    • The horn relay
    • The exterior lights