Complicated PDC problem, any good BMW techs on here?

[Bet2502]

One of my parking sensors wasnt emitting the clicking sound ( when you put your ear to it ) and has the PDC failure warning on the idrive so i bought another one and replaced it on saturday, expecting to go back to the idrive and see fault cleared but it was still showing, so i took it to a local diagnostic guy i know and had some faults cleared including this one but the fault wouldnt clear every time the car was started the fault was still there. I also checked the pcd control box in the boot for water damage etc etc , unpluged the connections and reconnected but the fault is still showing. The original sensor that wasnt working, is actually not broken as it was checked on another part of the car and it started clicking when reverse was selected.
Car is a E60 530d

Any ideas what it could be?

[martin mrt]

It sounds like a broken wire

[Nigel Worc's]

I've never had an E60,but, either a wire, as suggested, or, the output from the pdc.

I'm not sure of your location, but this chap is good ;

http://www.bmeuroservice.com/

[Bet2502]

Sounds like an expensive nightmare, im guessing a broken wire wont be easily found !

[FunBusMk2]

I spent £400 on a PDC fault on my E46 3-series. Still didn't fix it and it went through 2 main dealers.