why does my lexus not engage when i shift it into gear? on 2001 Lexus RX300

it showed code 0500 and /or 0700

Asked by for the 2001 Lexus RX300
First question would be is this the first time it has happened? Is there a check engine light that has come on recently? Has anyone checked the transmission fluid level? Sorry there is no quick answer, we need to start with the basics. Call me if you would like me to further diagnose the problem. Thanks, Scott Ken's Muffler & Automotive 970-484-6001