2004 Cadillac CTS Owner's Manual - Page 86

Immobilizer Operation Your vehicle is equipped with a passive theft-deterrent system. When trying to start the vehicle, if the engine does not start and the security light comes on, the key may have a damaged transponder. Turn the ignition off and try again. If the engine still does not start, and the key appears to be undamaged, try another ignition key. At this time, you may also want to check the fuse. See Fuses and Circuit Breakers on page 5-94. If the engine still does not start with the other key, your vehicle needs service. If your vehicle does start, the first key may be faulty. See your dealer who can service the theft-deterrent system to have a new key made. It is possible for the theft-deterrent system decoder to learn the transponder value of a new or replacement key. Up to 10 additional keys may be programmed for the vehicle. This procedure is for learning additional keys only. Canadian Owners: If you lose or damage your keys, only a GM dealer can service the theft-deterrent system to have new keys made. To program additional keys you will require two current driver's keys. You must add a step to the following procedure. After Step 2, repeat Steps 1 and 2 with the second current driver's key. Then continue with Step 3. The system works when you turn the key to ON. The key uses a transponder that matches an immobilizer control unit in your vehicle. The correct key will start the vehicle. Your vehicle has a special key that works with the theft-deterrent system. There is a transponder in the key head. If the key is ever damaged, you may not be able to start your vehicle. 2-20