GM Service Manual Online
For 1990-2009 cars only

The content theft deterrent option (UA6) combined with the remote control door lock option (AU0) is available on this vehicle. 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 horn sounds intermittently and the exterior 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 3 minutes once all the doors close. Once the 3 minute time expires the horn and the lights deactivate 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 to enable the normal arming procedure when exiting the vehicle:

  1. Close all the windows.
  2. Place the shift lever in the PARK position.
  3. Turn the ignition switch to the LOCK position.
  4. Remove the ignition key.
  5. Open any door.
  6. Use the power door lock switch or use the transmitter LOCK button to lock the doors.
  7. Close the doors to initiate the following conditions:
  8. 7.1. The SECURITY lamp illuminates solid on the dash for 30 seconds.
    7.2. The system is fully armed once the SECURITY lamp goes out.

Locking without Arming

Lock the doors manually with the inside lock knobs or with the front door lock key then close the doors to lock the vehicle without arming the system.

Alarm Activation

The armed system activates by sounding the horn and cycling the lights intermittently in unison with the opening of the trunk or any door. The BCM senses door opening through the door jamb switch. The BCM senses trunk opening through the trunk jamb switch. This alarm can be armed with the windows either open or closed since the system activation is dependent on door or trunk opening. The alarm disarms only when a door opens with the front door lock key or with the transmitter.

The doors and trunk can still open without alarm activation anything during the 30 second arming period. The security indicator lamp in the instrument panel flashes intermittently to remind the driver to relock the doors and arm the system. The system begins the arming process once the doors are locked with the use of the power door lock switch or the transmitter and all the doors shut. The SECURITY lamp illuminates solid for 30 seconds once the last door closes. The system is fully armed once the SECURITY lamp goes out.

Disarming the System


Object Number: 160872  Size: SH

The system disarms during the 30 second arming sequence under any of the following actions:

    • The opening of any door.
    • Unlocking the doors with the power door lock switch.
    • Unlocking the doors with the transmitter.
    • Unlocking the doors with the front door lock key.

Unlock the driver side door with the key or depress the UNLOCK button (1) on the transmitter to disarm the system after the system is fully armed or possibly tripped.

Theft Deterrent Switch

The front driver door is equipped with a theft deterrent switch. The theft deterrent switch attaches to the lock cylinder. The theft deterrent switch activates by movement of the lock cylinder. The theft deterrent 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 theft deterrent switch to disarm the system. The switch grounds the disarm input to the BCM when the lock cylinder turns to unlock door. The switch is serviceable. Remove the switch from the door latch to service. Refer to Doors.

Mechanical and/or corrosion facts on this switch may cause the system to self-activate intermittently. Check 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 one to correct this problem.

Door Jamb Switches

The content theft deterrent system uses the door jamb switches and the trunk jamb switch to activate the alarm. The BCM uses these switches to monitor door and trunk status. The BCM appropriately activates the following components if tripped or armed:

    • The parking lamps.
    • The headlamps.
    • The horn.

Horn, Parking Lamp and Headlamp Relays

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

    • For the horn.
    • For the exterior lamps.
    • For the headlamps.

The BCM solely controls and actuates the relays with the exception that the horn relay can also activate through the steering wheel contacts.

Security Lamp


Object Number: 160874  Size: SH

The SECURITY lamp (1) circuit is an indicator lamp output. The lamp illuminates under various operating conditions. For example, the lamp illuminates during the five second bulb test at key on. The SECURITY indicator lamp illuminates solid for 30 seconds. The system is fully armed once the SECURITY indicator lamp goes out.

The immobilizer system is standard equipment on this vehicle. The immobilizer system design prevents vehicle theft by interrupting the engine operation. Many other ignition-related theft deterrent systems deter starting of the engine if the key is determined to be incorrect. The immobilizer system allows the vehicle to start for a very short period regardless of the ignition key (assuming the mechanical cuts are correct). The engine operating functions interrupt and the engine stalls if the immobilizer system does not recognize the transponder identification code of the ignition key. Refer to System Operation for additional information on the operating characteristics of the immobilizer system. 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 EBTCM.
    • The ECM.

The immobilizer system design interrupts the engine operation if the immobilizer system does not recognize the proper transponder input from the ignition key. Many systems prevent the engine to start until the proper key is used. The immobilizer system allows the engine to start. The immobilizer then performs security checks of the key. The ECM requests the character of the transponder identification code from the theft deterrent module approximately 20 - 130 milliseconds after the engine starts. The engine control functions interrupt immediately (maximum 1.5 seconds after the ignition is On) and the engine stalls with an incorrect code. The engine functions remain uninterrupted with a correct code.

An invariable identification code emits from the transponder (installed in the ignition key head) to achieve this. The invariable identification code is read without battery contact via the theft deterrent module. A voltage creates and is read by the ECM through the theft deterrent module when the identification code signal is introduced to the magnetic field generated by the coils of the theft deterrent module. The ECM compares this value to a value stored in the memory. The ECM then determines whether to allow continued engine operation.

The range of the transmitting and receiving antenna on the theft deterrent module is so that a second key with transponder on a keyring is not addressed (maximum 2 - 3 cm reading distance). The transmission of the ignition key transponder identification code is secure under any ambient condition.

Immobilizer Control Module

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 ECM. The ECM 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.

Reprogramming the Immobilizer

Use a scan tool to reprogram the system if replacement of the theft deterrent module or the ECM is necessary.

  1. On the Immobilizer Menu of the scan tool, select F3: Special Functions.
  2. Select F4: Program Immobilizer.
  3. Follow the on-screen instructions.
  4. Use the scan tool to program the keys and relearn the ECM to the new immobilizers frequency code.

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 ECM through the theft deterrent module. The transponder is a small magnet. Therefore, it does not require battery power. The transponder never requires replacement under normal operating conditions.


Object Number: 160867  Size: SH

The ignition key head (1) contains the transponder (2). The transponder does not require battery power. The transponder (2) never requires replacement under normal usage. Service the transponder (2) and the ignition key (1) only as an assembly. Reprogram the system with a scan tool when replacing a key.