GM Service Manual Online
For 1990-2009 cars only

The ignition lock cylinder and keys do not contain any coded electronic components. The lock cylinder housing contains the coded electronic components. Changing an ignition lock cylinder or replacing a key is a purely mechanical process which does not affect the vehicle theft deterrent system. To replace an existing key, simply cut a new key to match the existing one. If no keys are available, the lock cylinder must be changed. To change the lock cylinder, simply replace the existing lock cylinder with one of the same type.