Battery will go dead after three or four days of sitting

The code is your passenger dimming control unit. So you may have a bad door switch. Best thing to do here is to go back to the site and check how to check for battery drain. Follow the steps to find it. If doing what it says and you get no results and still have a drain, disconect the abs unit as they have been known to have a bad transistor in them athat will drain the battry. It is repairable. For around $150-175

The sitch in the door jam that operates the interior lights when you open the door/doors