Car Electronics Questions? Ask an Electronics Expert for Answers ASAP
Here's the instruction relevant to this unit seeing as it isn't a wiring issue:
User error, or that it's a cheap head unit... most likely that it's a cheap unit. I would consider a replacement if it's still under warranty, you'd have to take it back to the shop or call the hotline in the manual for that kind of service. Sony ain't so great at the mobile electronics franchise, not in comparison to the rest of their product line.