I dont think it can be increased... Rear Parking Assistance is more of an on-off option rather than something you can continuously alter. I think you could swap some custom circuit elements as a DIY to make the system louder (as in put in an amplifier) but for that you would have to know the wiring.Does anyone know if the backup sensor volume can be increased. It is hard to hear if there is any background noise especially in a Volante with the top down.
Thanks, Ian