Patent ID: 6888265

Claim:
A method of providing security for a motor vehicle having propulsion apparatus and an ignition system having an on state providing electric power for operation of the propulsion apparatus and an off state withholding electric power from the propulsion apparatus, the ignition system further having a receptor for an ignition control key, the method comprising the steps: monitoring the ignition system to detect a change between the on state and the off state; responsive to a detected change in the ignition state, initiating electromagnetic communication apparatus in the receptor for interrogation and validation of a key therein with reference to stored security data; if the detected change in the ignition state is from the off state to the on state, authorizing vehicle engine operation if a key in the receptor is validated and preventing vehicle engine operation if no such key is validated; if the detected change in the ignition state is from the on state to the off state, generating a key in status datum having a first value if a key in the receptor is validated and a second value if no such key is validated; and responsive to an open state of a predetermined vehicle door while the key in status datum is generated with the first value, generating a warning signal, whereby the warning signal indicates that a key is left in the receptor with the propulsion apparatus not operating and the predetermined vehicle door open.