I Fixed those problems on my 508, but it's the exact same part as on the C5 X7 and the C6
after almost 3 months having the issue, and after I couldn't find this solution that worked for me, anywhere in the forums (except from a russian forum)
I want to share with you my issue and the repair I did to the EPB, and hopefully it would help many more people in the future
I made a full video about the process, not leaving behind the frustrating moments of not getting the issue fixed.
I added chapters for people who may not want to watch the whole video.