Encoded PATS Keys

PATS uses a special ignition key that is larger than a conventional ignition key because it contains a permanently installed electronic device called a transponder. Each transponder contains a unique encrypted identification code which is one of a very large number of combinations. The addition of this transponder to the key makes it an "encoded" key. The PATS key does not require batteries and should last the lifetime of the vehicle. Each PATS key must be programmed into the PCM before it can be used to start the vehicle. There are special general procedures that must be carried out if a new PATS key is necessary. Refer to Key Programming Using Diagnostic Equipment  or Key Programming Using Two Programmed Keys .