id just take power away from the radio, that will disable it. see if the code goes away.

if it dont it could be the pcm is crapping out. you can get replacements from a junk yard or ebay for like 40 bucks of same year and model as your car, but if you have inspection it will fail because the vin wont match. on ebay theres sellers who can set the vin for your year and model for like 150 ish.