M3 SMGII

Dear members,

I have a problem with my PDC sensors on my 2005 E60

2 months ago 4 (2 in front and 2 rear) of the sensors wore broken, I replaced them by myself. I bought the sensors on Ebay.
Everything went fine, untill 2 days ago. My PDC suddenly stopped working. I went to work in the morning and they were all fine. But in the evening when I wanted to go home my BC says " PDC Failure".

I've seen that you can test the sensors etc. They are supposed to have a "ticking" sound. The problem is none of them are ticking! I'm pretty sure that all my sensors are ok.

Could it be the PDC module? But how can I test it?

Thanks in advance!