Ive had problems with the PDC for the last month and finally replaced a faulty sensor today, but on testing the others Ive found that 6 of the 8 sensors dont apear to be working (ie bleep when they detect an object) but there are no error message on the display!

Ive had sensors fail previously but they have always generated a fault on the display -do they fail passively?

At £100 a shot from the dealers this will be very expensive!
Ive found them on the bay a lot cheaper but unpainted! can you paint them with a rattle can as the dealer says you cant?