Problem w/radio sound disappears

Hi, I have a 06 TL Non Navi and while I'm driving, sometimes the sound goes away, the radio screen is still on but I can't hear anything, or turn off the radio, and I can't change to cd / radio with the stereo, but with the steering wheel I can change, I have to turn the car off and on to listen again.
Has anyone had this problem?, I already search but in the post with a similar problem are not solved. Sorry for my english xD

Regards