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 immobilizer system is standard on this vehicle. 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 park 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. Turn the ignition key to LOCK and remove the key.
  3. Have all passengers exit the vehicle.
  4. Close all doors, hood and rear compartment lid.
  5. Press and release the door lock button on the transmitter.
  6. • The LED on the transmitter will flash.
    • All doors lock.
    • Hazard warning lamps flash once.
    • Theft Deterrent mode is activated.

    Important: If the key is inserted into the ignition key hole, the transmitter will not operate the theft deterrent system.

  7. The security indicator light starts flashing once every 0.8 seconds. The system is not 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 intelligent switching unit (ISU) senses door opening through the door contact switch. The ISU senses rear compartment lid opening through the rear compartment lid switch. The ISU senses hood opening through the hood ajar switch. This alarm can be armed with the windows either open or closed since the system activation is dependent on 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 LOCK/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 ISU 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 park 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 ISU uses these switches in order to monitor door and rear compartment lid status. The ISU appropriately activates the following components if tripped or armed:

    • The park lamps
    • The siren

Siren and Parking Lamp Relays

The internal ISU relays provide power for the following components when the alarm system activates:

    • The ark lamps
    • The siren

The ISU solely controls and actuates the relays with the exception that the park lamp relay can also activate through the light switch.

Security Indicator

The security indicator is located on the instrument panel. The LOCK command from the transmitter will place the ISU 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 CTD is designed to sound the siren and flash the exterior lamps when the system is armed and when the intelligent switching unit (ISU) 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
    • The ignition switch transition from the LOCK position.

Alarms

Operation of the siren and exterior lamps when activated, is controlled by the ISU. When the alarm is active, the ISU cycles the siren and park lamp. During this cycle, power is applied the siren and park lamps and then removed.

The ISU will remain in the Alarm state for 30 seconds or until a valid input to disarm the ISU is received.

Arming

The vehicle is armed when the ISU 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 remote transmitter while the theft deterrent system is armed, the doors will automatically lock 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 left front door is unlocked with a key, the tamper switch closes. This grounds the door's input to the ISU. 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 ISU for RKE system. When the ISU receives a valid key transmission from the remote transmitter, it unlocks the doors. Therefore the ISU 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.

Security Indicator

The ISU provides a ground in order to illuminate the security indicator. The system is armed when the lamp is flashing.

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 operate independent of each other. 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 Control Module - Immobilizer

The theft deterrent control module mounts to the steering column. The theft deterrent control 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 control module makes no determination as to the validity of the transponder key while the theft deterrent control module receives the signal from the transponder key. This is done solely by the ISU. The ISU 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 control module cannot be disassembled. Additionally, the theft deterrent control 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 ISU 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.