P0446 code

P0446 is identifing a fault in the evaporative vent control circuit. This could be one of several items. It will not mean replacing the whole circuit (wiring, valves, evap cannisters, flow switches etc.) On the corrolla, the item that generally causes this is the rear vent flow switch which will cost about 30 bucks and is located just ahead of the fuel tank under the car. It can be replaced by simply removing a screw and pulling the hoses off. The screw is often rusted and will not come out. This means cutting the old screw off and drilling a new screw hole.