GM Service Manual Online
For 1990-2009 cars only

Content Theft Deterrent (CTD) Operation

The content theft deterrent system operates separately from the immobilizer system. The content theft deterrent system design provides a warning in the event of forced entry through the doors or the rear compartment lid. The alarm system trips in the event of forced entry. The siren sounds intermittently and the turn signal lamps flash in unison under the alarm system. The alarm remains active as long as any door remains open. The alarm continues to sound for 30 seconds once all the doors close. Once the 30 second time expires the horn and the lights deactivate, the doors lock and the system returns to an armed state. The content theft deterrent system does not affect the engine starting or the engine operation.

Arming the Content Theft Deterrent System

Perform the following steps in order to enable the normal arming procedure when exiting the vehicle:

  1. Close all the windows.
  2. Important: If the key is inserted into the ignition switch, the transmitter will not operate the anti-theft system.

  3. Turn the ignition key to LOCK and remove the key.
  4. Have all passengers exit the vehicle.
  5. Close all doors, hood and rear compartment lid.
  6. Press and release the door lock button on the transmitter.
  7. • The LED on the transmitter will flash.
    • All doors lock.
    • Hazard warning lamps flash once.
    • Anti-theft mode is activated.
  8. The security indicator light starts flashing once every 0.8 seconds. The system is now activated.

Alarm Activation

The armed system activates by sounding the horn and intermittently cycling the lights in unison with the opening of the hood, rear compartment lid or any door. The remote control door lock receiver (RCDLR) senses the door opening through the door contact switch. The RCDLR senses the hood opening through the hood contact switch. This alarm can be armed with the windows either open or closed since the system activation is dependent on the door, hood, or rear compartment lid opening. The alarm disarms only when a door opens with the key or with the transmitter.

Disarming the System

Unlock the driver side door with the key, or depress the UNLOCK button on the transmitter in order to disarm the system after the system is fully armed or possibly tripped.

Theft Deterrent Switch (Tamper Switch)

The front doors and rear compartment are equipped with tamper switches. The tamper switch attaches to the lock cylinder. The tamper switch activates by movement of the lock cylinder. The tamper switch activates under the following conditions:

    • Rotation of the lock cylinder caused by forced entry
    • The in-and-out movement caused by forced entry

Additionally, use the tamper switch in order to disarm the system. The switch grounds the disarm input to the remote control door lock receiver (RCDLR) when the lock cylinder turns in order to unlock the door. The switch is serviceable. Remove the switch from the door latch in order to service the switch.

Mechanical failure and/or corrosion on the switch may cause the system to self-activate intermittently. Inspect the lock cylinder for looseness if this happens. Any movement of the lock cylinder with this switch can cause the switch to activate the alarm. One possible cause for this problem may be a lock cylinder retainer that is not firmly installed to the lock cylinder. Reinstall the lock cylinder retainer or replace the lock cylinder retainer with a new retainer in order to correct this problem.

If the turn signal lamps flash once when the LOCK/UNLOCK button on the transmitter is pressed, that means the content theft security system alarm was triggered.

Door Jamb Switches

The content theft deterrent system uses the door jamb switches and the rear compartment lid switch in order to activate the alarm. The remote control door lock receiver (RCDLR) uses these switches in order to monitor door and rear compartment lid status. The RCDLR appropriately activates the following components if tripped or armed:

    • The turn signal lamps
    • The siren

Siren and Turn Signal Lamps

The internal remote control door lock receiver (RCDLR) relays provide power for the following components when the alarm system activates:

    • The turn signal lamps
    • The siren

The RCDLR solely controls and actuates the internal relays. The turn signal switch activates the turn signal lamps separately.

Security Indicator

The security indicator is located in the clock on the top of the instrument panel. The LOCK command from the transmitter will place the RCDLR in the armed mode and the security indicator will flash. The security indicator will flash until the system is disarmed.

Content Theft Deterrent (CTD) Circuit Description

The content theft deterrent system is designed to sound the siren and flash the exterior lamps when the system is armed and when the remote control door lock receiver (RCDLR) detects an unauthorized entry. An unauthorized entry can be any of the following conditions:

    • Door opened
    • Forced entry into the rear compartment lid
    • Forced entry into the engine compartment

Alarms

Operation of the siren and exterior lamps when activated, is controlled by the remote control door lock receiver (RCDLR). When the alarm is active, the RCDLR energizes the siren and turn signal lamps. The RCDLR will remain in the Alarm state for 30 seconds or until a valid input to disarm the RCDLR is received.

Arming

The vehicle is armed when the remote control door lock receiver (RCDLR) receives a door LOCK command from the remote transmitter or when it determines that the doors have been locked with a key. The theft deterrent system also has an automatic locking feature. If the doors are unlocked with the remote transmitter while the theft deterrent system is armed, the doors will automatically relock after 30 seconds unless any of the following events occur:

    • The door is opened.
    • The ignition is turned ON.
    • The rear compartment lid is opened.
    • The hood is opened.

Disarming

When the driver door is unlocked with a key, the tamper switch closes. This grounds the door's input to the remote control door lock receiver (RCDLR). The system is then disarmed and the alarm state will not become active when the door is opened.

The remote control door lock receiver is an internal part of the RCDLR for the remote keyless entry (RKE) system. When the RCDLR receives a valid key transmission from the remote transmitter, it unlocks the doors. Therefore the RCDLR recognizes this in the same manner as a valid door lock switch disarm input.

Turning the ignition switch to any position out of LOCK will not disarm the system when the alarm is active.

Vehicle Theft Deterrent (VTD) Operation

The immobilizer system design prevents vehicle theft by interrupting the engine operation. The immobilizer system prevents the vehicle from starting. The engine operating functions interrupt if the immobilizer system does not recognize the transponder identification code of the ignition key. The immobilizer system and the content theft deterrent system do not interact. The system includes the following components:

    • The ignition key
    • The column-mounted theft deterrent module with integrated antenna
    • The transponder
    • The engine control module (ECM)

Theft Deterrent Module (Immobilizer)

The theft deterrent module mounts to the steering column. The theft deterrent module contains an antenna arranged in a ring around the ignition lock cylinder. The transponder enters the very limited reading range (2-3 cm) of the antenna with the ignition in the RUN position when the transponder key inserts in the ignition lock cylinder. This guarantees that only the key that is inserted in the ignition lock cylinder can have its transponder code audited. This excludes the possibility of interference from other transponder keys in the vicinity. The theft deterrent module makes no determination as to the validity of the transponder key while the theft deterrent module receives the signal from the transponder key. This is done solely by the remote control door lock receiver (RCDLR). The RCDLR performs all decision making processes. Therefore, any theft attempt by hot-wiring the theft deterrent module or any wiring harness will not result in a successful bypass of the system. The theft deterrent module cannot be disassembled. Additionally, the theft deterrent module must be serviced as an assembly.

Transponder

The ignition key head contains the transponder. The transponder emits a magnetic field. This magnetic field interacts with the magnetic field generated by the coils of the theft deterrent module creating a voltage which is read by the remote control door lock receiver (RCDLR) through the theft deterrent module. The transponder is a small magnet. Therefore, the transponder does not require battery power. The transponder never requires replacement under normal operating conditions.

The ignition key head contains the transponder. The transponder does not require battery power. The transponder never requires replacement under normal usage. Service the transponder and the ignition key only as an assembly. Reprogram the system with a scan tool when replacing a key.

Security Indicator

The security indicator is located in the clock on the top of the instrument panel. The light emitting diode (LED) displays the immobilizer system status. The immobilizer contains the LED driver hardware for direct connection of the LED.

Status LED Modes

Status LED

Immobilizer System Status

Note

Blinking

Active

Ignition OFF

Blinking

Active

    • Invalid key detected
    • Ignition ON

OFF

Inactive

    • Valid key detected
    • Ignition ON

Blinking

Active

    • VIN-code is different between ICU and ECM in learned state
    • Ignition ON

ON

Active

    • Transponder reading error
    • Ignition ON

Blinking

Active

    • Reading exciter ASIC error
    • Ignition ON