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 unauthorised vehicle entry is detected. However, the CTD System does not affect engine starting.

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

    • When the hood has been opened without disarming the CTD system.
    • When any door is opened without being unlocked using the keyless entry transmitter.

The components of the system are:

    • The body control module.
    • The door ajar switches.
    • The hood ajar switch.

Arming the CTD System

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

Use the following procedure in order to arm the system:

  1. Turn OFF the ignition.
  2. Exit the vehicle.
  3. Lock the doors with either the LOCK button on the transmitter or by the driver door external key cylinder lock. The system will transition directly to the locked state with the indicator on steady.
  4. If the doors are open when locking is requested, a warning of 5 horn chirps will occur. Additionally, if the drivers door is open when locking is requested, the driver door will initially lock, then quickly unlock again.
  5. The system will arm approximately 30 seconds from the time that the system has entered the locked state. When the indicator transitions to flashing slowly, the system is armed.

Disarming an Armed System/Silencing an Alarm

If system arming has been requested by the keyless entry transmitter, it must be disarmed.

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

To disarm the CTD system perform one of the following:

  1. Press the UNLOCK button on the keyless entry transmitter.
  2. Insert a valid key into the ignition and start the vehicle.

Simulated Armed Mode

If a vehicle remains disarmed with all doors closed for an extended time period (60 seconds), the CTD system will enter Simulated Armed Mode. In Simulated Armed Mode, the system activates the alarm indicator to replicate the armed mode by flashing slowly. However if the power mode changes or if any doors are opened, the CTD system will turn off the lamp and not activate the alarm.

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 unauthorised entry, it activates the horns and exterior lamps.

When the BCM detects an unauthorised entry from the drivers door, the BCM will first enter the pre-alarm mode. The pre-alarm mode will command short chirps from the horn. If after 10 seconds the unauthorised entry still exists, the BCM will transition to the alarm mode. The horn and lamps will pulse for 30 seconds. Following the 30-second alarm period is a 5-second time-out. The CTD system will then re-arm.

Door Ajar Switches

The CTD system uses the integrated door ajar switches in the door latches as one method to activate the alarm. The 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 BCM monitors the following inputs:

    • The driver and passenger door ajar switches.
    • The hood ajar switch.
    • The transmitter LOCK/UNLOCK buttons; an internal function of the BCM.
    • The Passkey status--The BCM uses the Passkey 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.