[alwdad83]

Hi all
This is going to be long but I want the picture to be clear. I have searched on here before posting and couldn't find anything relative.
I'm hoping I can get some educated input on an issue I'm experiencing with my in-laws car. 318i e90 2009 LCI apart from a parrot kit (which I want to remove as he doesn't use it) the car is completely standard. About 6 months ago one day he went to his car and it was dead, charged it up, checked it over thinking possible battery which is 3 years old start/stop 5 year warranty job, Like for like. Installed and registered by myself.
Kept an eye on it all seemed well, battery was holding charge, alternator output was healthy which stumped me, didn't make sense. we could leave it for a week and it would still be ok. fast forward two months and one morning dead again.
Took the battery out, charged it tested it, seemed all ok so back in it went, checked the codes and the ones coming up would coincide with battery discharging.
Fast forward to last week Tuesday, the car had been in the garage for two days (it's garaged over night and if not using it for the day) and I started it and it came up with the yellow ramp light. So put he foxwell NT520 Procon it and had various codes (two I knew it would of had '30EA Nox cat sulphurised' present, which has been prevailing after two of the injectors failed so probably kaputz, the other '2EF7 Map thermostat activation' present, which a mahle unit is on order from autodoc) those being; 2DEC Power management battery not present Ran it up, took the mrs to aldi and back, garaged till the thursday that's when the battery was pancaked. Put battery on charge this time through the jump points, left it over night and checked battery voltage, full charge indicator lit up so removed, started up no problems checked codes and getting 9CB5 Not present. cleared codes, left it running for 10 minutes and switched off, locked up and stood thinking about what it could be?
That's when I heard the fuel pump activate for a couple of seconds then few seconds later various relays or solenoids clicking under the bonnet.
It was to the T every 30 seconds the fuel pump would activate the 10 seconds later would hear clicking of what is either relays or solenoids.
I've checked Ecu it's dry, cables and connections all seem sound physically, battery area is dry. Disconnected the battery, left 30 minutes and reconnected and all seems fine again.
I have video of it for better clarity but what is best way to share?
Googling suggests possible CAS issue, Facebook group hasn't yielded anything so here I am begging for your input
My 2006 330D (touch wood) has not given me any of the problems that his 318i has, it's driving me insane! please help