My Pioneer Avh-P5100Dvd Aux & usb port does not work?

my Pioneer Avh-P5100Dvd aux & usb port does not produce any sound. but the usb port reads the music but i dont be hearing any sounds through the speakers, but it is showing on the display screen that the music is been played.. is this because of bad wiring? please for ur help....best answers would be rewarded points.