GM Service Manual Online
For 1990-2009 cars only

When armed, the content theft deterrent (CTD) system 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 any door or the liftgate 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 key cylinder
    • After a battery reconnect, if the battery was disconnected with the CTD system armed

The components of the CTD system are:

    • Body control module (BCM)
    • Liftgate module (LGM)
    • Security indicator
    • Door ajar switches
    • Liftgate ajar switch
    • Driver door key cylinder switch

Arming the CTD System

Important: The system is not armed if the doors are locked manually. The keyless entry transmitter must be used to arm the CTD system.

Use the following procedure in order to arm the system:

  1. Place the shift lever in PARK.
  2. Turn OFF the ignition.
  3. Exit the vehicle.
  4. Lock the doors with the LOCK button on the transmitter. The system is in standby mode and will not start the arming timer until all doors are closed.
  5. The system will begin the arm sequence immediately after the last door is closed. If the keyless entry transmitter is used to arm the system after the vehicle doors are closed, the arm sequence will begin as soon as the LOCK command is received by the transmitter.

Locking The Vehicle Without Arming The CTD System

Locking the vehicle may be accomplished without arming the CTD system. Use of the manual door locks or using the key to lock the doors will lock the vehicle, but will not arm the CTD system.

Disarming an Armed System/Silencing an Alarm

If system arming has occurred, it must be disarmed.

Important: Using the power door unlock switch or manually unlocking the doors does not disable the CTD arm mode. Also, disconnecting the battery or pulling fuses does not disable the arm mode, since the BCM stores the CTD mode 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 Component 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 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. The system will re-arm immediately following an alarm event.

Liftgate Module (LGM)

The LGM receives input from the keyless entry transmitter, transferring information to the BCM via serial data. The BCM uses this information along with other information for activation and deactivation of the CTD system.

Security Indicator

The security indicator is illuminated by the instrument panel cluster (IPC) based on information, via serial data, from the BCM for CTD or from the theft deterrent module (TDM) for immobilizer. The CTD system uses the security indicator to inform the driver of system status prior to arming.

    • The CTD system controls the security indicator only when the ignition is OFF. The CTD system uses the indicator to identify system status.
    • The immobilizer system commands the IPC to control the security indicator only when the ignition switch is ON as a malfunction indicator. Refer to Immobilizer Description and Operation for more information on the immobilizer system.

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 a discrete input from each front door ajar switch. The rear door ajar switches are monitored by the BCM via a discrete input from each door ajar switch. If the BCM receives a signal indicating a door is opened when the CTD system is armed, the BCM activates the alarm.

Liftgate Ajar Switch

The CTD system uses the liftgate ajar switch as a status indicator to activate the alarm. The liftgate ajar switch is monitored by the BCM a discrete input from the switch. If the BCM receives a status signal from the liftgate ajar switch indicating it was opened without the keyless entry transmitter, 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 CTD system will immediately disarm.

Inputs

The BCM monitors the following inputs for CTD:

    • Door ajar switches
    • Driver door cylinder switch
    • Keyless entry transmitter LOCK/UNLOCK buttons; a serial data message from the RCDLR
    • Immobilizer status--The BCM uses the immobilizer status for disarming the system or silencing an alarm when the correct vehicle key is used to start the vehicle.
    • Liftgate ajar switch

Outputs

The BCM controls the following for CTD:

    • The horn relay
    • The exterior lamps