Hi chaps, I am a newbie so I trust you guys can help me ?

I picked up my new 2008 Mondeo 2.0 Diesel Auto Ghia yesterday and have noticed that the front and rear parking sensors are not working.

When I put the car in reverse the speaker gives the audio bleep for a moment and then I get nothing at all from either the front or rear sensors.

Can anyone help me please ?

Thanks
Pete