2008 Cadillac CTS Owner's Manual - Page 105

The security light will come on if there is a problem with arming or disarming the theft-deterrent system. The key uses a transponder that matches an immobilizer control unit in your vehicle and automatically disarms the system. Only the correct key will start the vehicle. If the key is ever damaged, you may not be able to start your vehicle. When trying to start the vehicle, if the engine does not start and the security light comes on, there may be a problem with your theft-deterrent system. 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 5-122. 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/retailer who can service the theft-deterrent system and 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 keys can be programmed for the vehicle. The following procedure is for programming additional keys only. To program a new key do the following: 1. Verify that the new key has 1 stamped on it. 2. Insert the current driver's key in the ignition and start the engine. If the engine will not start see your dealer/retailer for service. 3. After the engine has started, turn the key to LOCK/OFF, and remove the key. 4. Insert the key to be programmed and turn it to ON/RUN within five seconds of the ignition being turned to LOCK/OFF in Step 3. 5. The security light will turn off once the key has been programmed. It may not be apparent that the security light went on due to how quickly the key is programmed. 6. Repeat the Steps 1 through 4 if additional keys are to be programmed. In an emergency, contact Cadillac Roadside Service®. See Roadside Service on page 7-6. Do not leave the key or device that disarms or deactivates the theft deterrent system in the vehicle. 2-29