[Lexman8]

Originally Posted by Yelper85

Does anybody have any more info on this as I'm intrigued.

I read that it's something to do with the fuel system in a PHEV being 'sealed' to avoid (or slow down) petrol 'going off' because it would be theoretically possible for the fuel to be unused for weeks or months at a time.

From the manual:

Pressure equalisation of the fuel tank involves a certain delay in opening the flap. The message Preparing for refuel Fuel lid will be unlocked when ready appears in the driver display, and when the system is ready the message Ready for refueling appears in the driver display. If the internal combustion engine is switched on when the button is pressed, it is generally switched off and the car switches to electric mode.

After the fuel filler flap has been opened, refuelling must take place within about 15 minutes. After this, the valve that was opened by pressing the button to open the fuel filler cap is closed, and it is no longer possible to refuel because the pump nozzle cuts out.

If the valve is closed before refuelling is complete - press the button again and wait until the driver display shows the message Ready for refueling.