Remote control device for vehicles

A vehicular remote control device comprising:

• vehicular transmitter for transmitting a request signal;
• a portable unit for transmitting a response signal in response to the request signal transmitted thereto from said vehicular transmitter;
• vehicular receiver for receiving said response signal;
• control means for determining whether the response signal received by said vehicular receiver matches identification information stored in a vehicle or not, and controlling an operating state of a vehicle-mounted device depending on the determined result;
• and
• failure diagnosis means disposed in said vehicle for controlling said portable unit to diagnose said vehicular transmitter for failures by means of transmitting a failure diagnosis signal instead of the request signal from said vehicular transmitter;
• said portable unit having indicating means for indicating a failure status and means for operating said indicating means while prohibiting transmission of said response signal in response to said failure diagnosis signal.

A portable unit for use in a vehicular remote control device, comprising:

• an LF receiver circuit for receiving a request signal having a low frequency which is transmitted from a vehicle;
• an RF transmitter circuit responsive to said request signal, for transmitting a response signal having a radio frequency which includes identification information for controlling an operating state of a vehicle-mounted device on said vehicle;
• decision means for determining whether a failure diagnosis signal having a low frequency which is transmitted instead of said request signal is received by said LF receiver circuit or not;
• and
• indicating means for indicating a failure status, wherein said decision means operates said indicating means when it is judged by said decision means that said failure diagnosis signal is received by said LF receiver circuit.