Will dead battery in key fob prevent fuel door from opening on Porsche boxster?

yes, the key fob activates the centrral locking system. Using the "key in the door" method, will also prevent the front and rear trunks from opening, using the levers next to the driver's seat. When the key fob is used, the security of the car is "relaxed" and you can do anything. Without it, everything is secure.