My security light is on and my radio gets locked sometimes while I'm driving. Does anyone one know why this happens?

Yes, the anti theft system runs thru the radio. Either the radio is going bad and causing the antitheft to kick in, or the antitheft is bad and faulting the radio. I just went thru this in my girlfriends 01. Ended up installing after market radio and bypassing the security system. I bypassed thee antitheft security first, and the car worked just fine, but I didn't get any radio till I installed a new radio. Here Is a link to help with the antitheft http://vatspasslockpasskeysecurityhelp.yolasite.com/