A3 2.0 TFSI cut out now non start
 

Audi A3 2.0 TFSI*2007 '57 plate (BWA)
Hi all, be gentle it's my first time on here.
I went out to my customers car as mentioned above, it cut out and wouldn't start, just cranking.
I managed to get a code of 012555 (fuel pressure regulation below minimum). I banged the fuel pump in the tank as I couldn't hear anything and it gargled and started. Great I thought, nice easy repair. Fit new pump and it started fine. I used it for a few days to make sure it was ok before giving it back to him and hey presto it cut out on me as I was calling him to tell him to collect it!
Having delved deeper into it this is what i've found:
All fuses ok, non blown.
At the*fuel pressure reg*ive got 3.4volt? from fuse number 6 under bonnet which has 3.4V. If I pull relay number 1 out this voltage drops. No signs of any water or problems in this fuse box. Started to think it was an internal fault in the fuse box. Striped it down and all ok. Replace relays..still same. Looking at the data stream I have nofuel pressure.
Now back to the*fuel tank.
At the main plug to the fuel pump control module I have a constant live and earth (the 2 bigger wires) but nothing coming out of it to the pump. I can power probe 12V and get it to work and the car starts.
Finally heres my question...Is there another unit that tells the pump to work as and when or do I have a faulty fuel pump control module?