CCM is 'Comfort Control Module' and controls things like the leccy window, central locking, interior illumination, bulb checking system and all that jazz.
From your description it does sound like the CAN Gateway. Have a poke around in the pedal box area to see if it's wet around there. The CAN Gateway lives above the pedals and is an absolute pain in the hoop to access from down there. The easiest way to hoik it out is via the access panel in scuttle area. The wipers need to come out to get at it. I'll see if I can find some pics. Sounds like said panel is leaking on yours. It has a rubber seal which may have perished, or been accessed previously and not put back properly.
You don't need the exact same gateway, but the replacement one will likely need coding, which can be done with VAG-COM. It's just stores a list of model specific 'features' and designations, and options. The relevant ones for your car need to be enabled otherwise sh*t don't work, putting it bluntly!
