Troubleshooting guide:
OBD II Code P0440
Yes, if you open your gas cap and look closely at the sealing o-ring. Sometimes these get cracks in them and no longer seal completely, causing the evap sys to be unable to pull a vacuum on your gas tank. This will trip a P0440. A crappy aftermarket gas cap will cause this as well. Make sure it is a Porsche OEM gas cap.
Good hunting!