legacycentral bbs

for some reason my keyless entry works when it wants to. I have a BD5 sedan. The sensor is situated with the map lights on the ceiling. I can sit in the car and press the key and lock/unlock the doors (so there is no chance of interference from the window) then suddenly it doesn't work. It might stop working for a few hours or a few days.
Has anyone experienced this before. Any comments would be appreciated.

maybe the battery in the remote?

I wish it was that simple. The problem happens with fresh battery.