I recently bought a 2009 Volvo S40 from a Citroen main agent. At my request, and cost,they fitted (Citroen) Rear Park Assist. The sound is almost inaudible. This I discovered only at home, at some considerable distance from the supplier. They will adjust the volume but tell me that I need to make an appointment and leave the car with them. Does anyone know I can make this adjustment?

Thanks.