Just bought my Sovereign 3.0 TDVi and a selling point was the all round parking sensors except the only work intermittenty!
As I pull up outside my drive to reverse in, before I even have chance to select reverse (it's an auto) the sensors malfunction and continuously buzz, therefore as I cannot see the end of the long boot I have no idea how far back I can park! It will also continuously buzz when I brake at junctions and if I have to squeeze between vehicles the front sensors will buzz for a few seconds.Of course when it continuously buzzes I can turn the sensors off but it is spoiling my enjoyment of a lovely car.......

We are also exeriencing exhaust fumes in the cab. :-(

 

If it really is a 3.0 litre Tdvi then it isn't an X350/358. I think that size engine was fitted in the later X351. What year is your car ?

 

2006 and you are correct, it is a 2.7 like yours.

 

The weak link in the system are the sensors themselves, they can be intermittent or continuously beeping indicates two or more on the blink.