Abstract: The present invention teaches a method for preventing the use of an unauthorized reproduction of a remote unlock signal. In this scenario, the unauthorized reproduction occurs by jamming the receiver from receiving the remote unlock signal while intercepting the remote unlock signal. Generally, the remote unlock signal is transmitted by a transmitter to the receiver within a vehicle having a lock, wherein the receiver initiates an unlock command in response to receiving the transmitted remote unlock signal, and the vehicle lock being mechanically actuated by a key or electronically initiated by the unlock command in a previous locking session.

Abstract: A system for detecting failure in one of a plurality of remote sensing devices utilizes a plurality of counters, each associated with one of the remote sensing devices. Each counter is initially loaded with an initial value. When a signal is received from a remote sensing device, its associated counter is reset to the initial value while the counters of the other remote sensing devices are stepped down. If a sensing device does not send a signal, its associated counter is stepped down numerous times, but never reset to the initial value. When a counter reaches a pre-determined value, typically zero, the associated sensing device is deemed to have failed.