1995 Cadillac Seville Owner's Manual - Page 73

The squarekey is for the ignition only. It has a resistor pellet which is part of the vehicle's PASS-Key% system. The oval key isfor the doors and all other locks. When a new Cadillac is delivered, the dealer removes the plug from the key. The plug has a code on it that tells the dealer ora qualified locksmith how to make extra keys. However, the ignition key does not have a knock-out plug. The ignition key has abar code tag attached to it. Your dealer or qualified locksmith, by reading the bar code tag, can then make your key. - 2-2