Back in 2007, my 56 plate Focus 2.0 TDCi threw up a "power steering failure" warning one day when I started the engine. The PS was definitely not working. I switched the ignition off and on a couple of times and the warning disappeared and the PS was working fine. It was under warranty so I got it checked out by Ford but got the usual "no faults logged so we can't do anything".
The problem never reappeared ..... until last week. Its done it twice again this week. Each time, turning the ignition off and on fixes it. The car has a combined electric pump and reservoir and I'm sure its just a dodgy electrical connection. I can see three electrical plugs on top of the unit (one a beefy power supply). Two of the plugs I've been able to remove and there isn't any moisture/corrosion. The third plug I can't get off yet. Its awkward to get hold of but maybe its corroded.
I just wondered what other electrical bits are there in the system? I've heard mention of steering angle switches. I assume they are on the rack?