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:

    • Forced entry into the passenger compartment
    • When any door is opened without first using the key to unlock the vehicle or receiving an UNLOCK command from a valid keyless entry transmitter.

The components of the system are:

    • Remote control door lock receiver (RCDLR)
    • Door ajar switches
    • Body control module (BCM)
    • Driver door key switch
    • Power door lock switches

Arming the CTD System

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 power door lock switch or remote keyless entry transmitter must be used to arm the content theft deterrent (CTD) system.

  5. Lock the doors with either the power door lock switch or the LOCK button on the transmitter. The system is in standby mode and will not begin the arming timer until all doors are closed.
  6. The system will begin the arming timer immediately after the last door is closed. This delay is shown by the theft LED indicator ON STEADY. When the indicator transitions to OFF, the system is armed. After the theft LED indicator transitions to OFF, the theft LED will begin to flash slowly.

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 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 been requested by the power door lock switch or the keyless entry transmitter, it must be disarmed.

Important: Using the power door unlock switch or manually unlocking the doors does not disable the content theft deterrent (CTD) arm mode. Also, disconnecting the battery or pulling fuses does not disable the arm mode, as the body control module (BCM) stores the CTD mode status in memory.

    • To disarm the CTD system in standby mode, perform one of the following:
       - Press either power door unlock switch.
       - Use the key to unlock either front door.
       - Press the UNLOCK button on the keyless entry transmitter.
       - Insert a valid key into the ignition and switch to the ON position.
    • To disarm the CTD system in the armed mode:
       - Use the key to unlock either front door.
       - Press the UNLOCK button on the keyless entry transmitter.
       - Insert a valid key into the ignition and switch to the ON position
    • To disarm the CTD system when activated (alarming mode).
       - Use the key to unlock either front door.
       - Press the UNLOCK button on the keyless entry transmitter.
       - Insert a valid key into the ignition and switch to the ON position.

CTD Circuit Description

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

Remote Control Door Lock Receiver (RCDLR)

The keyless entry system can arm and disarm the CTD system. When the remote control door lock receiver (RCDLR) receives a door lock or unlock signal from the transmitter, the RCDLR sends a message via serial data to the body control module (BCM) to perform the appropriate arm/disarm functions.

Door Ajar Switches

The CTD system uses the door ajar switches in the door latch assemblies as one method to activate the alarm. The BCM monitors all door ajar switches via a discrete input from each door latch assembly or door jamb switch. If the BCM receives a ground signal from any door ajar switch when the CTD system is armed, the BCM will activate the alarm.

Body Control Module (BCM)

The CTD system is an internal function of the BCM which utilizes 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. The BCM has 4 basic modes (disarmed, standby, armed, and alarm) for operating the CTD system. The different modes are described below.

  1. The BCM has the CTD system in a disarmed mode until the following conditions are detected:
  2. • Ignition key turned to the OFF position.
    • Any door open.
    • Doors locked by either the power door lock switch or the LOCK button on the keyless entry transmitter.
  3. The BCM enters the standby mode when the above conditions are detected and a vehicle door is open. In standby mode, the BCM commands the theft LED to flash quickly. If all the doors are closed and the LOCK button on the transmitter is used, the BCM enters the delayed mode.
  4. When the last door is closed, the BCM enters the armed mode. In armed mode, the BCM commands the theft LED to flash slowly.
  5. When the BCM detects a forced entry, the BCM enters the alarm mode. The BCM activates the horns and exterior lamps for 30 seconds. This is followed by a 3 minute time-out with the horn no longer active. If no new intrusions are detected after the time-out, the horn is not active. The system must be disarmed or the intrusion condition removed after the time-out for the system to exit alarm mode.

Driver Door Key Switch

The driver door key switch is an integral part of the driver door lock cylinder and provides a discrete input to the BCM. The BCM utilizes each this input to disarm the CTD system. Inserting a key and turning to the UNLOCK position will disarm the CTD system.

Power Door Lock Switches

The power door lock switches are used to either arm or disarm the CTD system. Pressing the LOCK position will cause the CTD to arm after all doors are closed. Pressing the UNLOCK position will disarm the CTD system only if still in stand-by mode.

Important: The CTD system can be armed with the windows or sunroof open.

Inputs

The BCM monitors the following inputs:

    • Driver door key switch
    • Door ajar switches
    • Door lock switch - Driver and Passenger
    • Transmitter LOCK/UNLOCK buttons, serial data message from the RCDLR

Outputs

The BCM controls the following:

    • The horn relay
    • The exterior lights