2007 Buick LaCrosse Owner's Manual - Page 108

It is possible for the PASS-Key® III decoder to accept the transponder value of a new or replacement key. Up to 10 keys may be programmed for the vehicle. The following procedure is for programming additional keys only. If all the programmed keys are lost or do not operate, see your dealer or a locksmith who can service PASS-Key® III to have keys made and programmed to the system. To program the new key do the following: 1. Verify that the new key has PK3 stamped on it. 2. Insert the master key in the ignition and start the engine. If the engine will not start, see your dealer for service. 3. After the engine has started, turn the key to OFF, and remove the key. 4. Insert the key to be programmed and turn it to RUN within five seconds of removing the original key. 5. The SERVICE THEFT SYSTEM warning message on the DIC will turn off, once the key has been programmed. It may not be apparent that the SERVICE THEFT SYSTEM warning message went on due to how quickly the key is programmed. 6. Repeat Steps 1 through 5 if additional keys are to be programmed. If the SERVICE THEFT SYSTEM warning message appears and stays on the DIC while the vehicle is being driven, the engine will be able to be restarted if it is turned off. Your PASS-Key® III system, however, is not working properly and must be serviced by your dealer. The vehicle is not protected by the PASS-Key® III system at this time. If the PASS-Key® III key is lost or stolen, see your dealer or a locksmith who can service PASS-Key® III to have a new key made. 108