The present invention provides a method of accessing a mobile vehicle using a
wireless communication system. A vehicle communication device is placed into a
first communication service sleep mode of a sleep cycle. It is determined if a
first communication service is currently available to the vehicle communication
device. If the first communication service is available, the vehicle communication
device remains in a first communication service awake mode for a first interval
of the sleep cycle. If the first communication service is not available, the vehicle
communication device remains in the first communication service sleep mode for
the first interval of the sleep cycle. Programs and systems of using the method
are also provided.