My friends have both set theirs to "0000"
http://global.scei.co.jp/manual/pdf/SCPH-30001.pdf should lead you to the product manual, page 19 address the parental control. Apparently code "7444" deletes the old code (but you have to press select when it asks you for the code, I guess. All there on page 19). Then you can follow the steps to turn it off.