1998 Cadillac DeVille Owner's Manual - Page 74

The square keyis for the ignition only. It has a resistor pellet whichis part of the vehicle's PASS-Key% system. When a new vehicleis delivered, the dealer removes the a plug from the doorkey. The plug has code onit that tells the dealer a qualified locksmith how to make or extra keys. The ignition key has code tag attached a bar to itrather thana knock out plug. Your dealer or qualified locksmith can make extra ignition keys by reading thebar code tag. Keep thebar code tag and the door key plugs a safe in place. If youlose your keys, you will be able to have new ones made using the plug bar code tag. or The oval key is for the doors andall other locks. NOTICE: Your vehicle has a number of new features that can help prevent theft. can have a lot You of trouble getting into your vehicleyou ever if lock your keys inside and you have to may damage your vehicleto get in. Be sure you have extra keys. 2-3 \ .