2008 Focus LT issues - electrical?

[numloxx]

Hi guys,

I'm not quite sure what to put in the title as it's a few things that I'm having trouble with.

I was driving on the freeway in Perth today and suddenly a few warnings came up on my dashboard:
Speed Limited Mode, Engine Systems Fault, Transmission Malfunction, Power Steering Fault. I pulled the following fault codes using the Torque App and an ODB2:
U1900 - Network,
P0571 - Powertrain, Cruise Control/Brake Switch A circuit,
P2121 - Powertrain - Throttle Pedal Position Sensor/Switch D circuit range/performance
U1900 Network

I went back home and disconnected the battery for 30 minutes then connected again. I drove on the freeway again and was going to a friend's house who is more mechanically inclined than I am.

It then came up with:
P0231 Powertrain - Fuel Pump Secondary Circuit Low,
P0571 again
P2121 again
U0073 - Network
U1900 again
U2012 - Network
U2197 - Network
U2200 - Network

I lost my rpm and speedometer and also fuel and battery levels, all went to 0 (fuel and battery a bit slower of course), with all my warning icons. Went away again, with messages as before. I lost power steering this time.

Gauges all fixed themselves and power steering returned. Happened a few more times.
My friend and I did some test driving, and we thought it might either be the throttle sensor, instrument cluster, or the ECU/PCM ?

Any assistance would be greatly appreciated, as I'm hoping to fix this myself, as I'm not in a good spot with work at the moment, casual jobs only, and hoping to be able to fix it myself, but will take it to Ford or RAC if I have to.

On the drive home on the freeway, all was ok.. but driving around my friend's house, the dashboard constantly conked out several times driving under 60km etc.