I've just had the same problem, 12 plate Xv, power steering light came on, but with no need to turn as I was reversing straight out of the garage. Light did not clear an power steering didn't work on the driveway, so I abandoned the journey. Car was left out overnight, it snowed, but this morning, no problem, car started, light cleared and steering worked fine. Battery shouldn't be a problem as was replaced last year. So puzzled what to do, if anything.