In March 2012, the EPS light came on in my Elantra and the power steering went out. At first, when I would restart the car, the light would go off for a time and the power steering would work, but soon it would revert to EPS light and no power steering. I took it to the dealer who ran a couple of updates and tightened a loose connection. All was well until January 2013, when the EPS light came on again and the power steering quit working. No amount of restarting, crossing fingers, or using bad language, would make the light go off and return the steering to normal. Back to the dealer I went. This time the verdict was bad. The car was in need of a $2,400 steering column. I got a second opinion from my trusted mechanic who verified the need for a new steering column. At least this guy was only going to charge me $2,000. Being a public school teacher, I did not have that kind of cash lying around so drove it with no power steering. I know this is unsafe but did not have too many other options. Now, in July 2013, my battery (which I had replaced in January 2013) died. Seriously died. Not a sound, not a click. When the car was jump-started, imagine my surprise when the EPS light was out and the power steering worked. After a new battery was in place, the power steering continued to work just fine - so far. My question is this. Would a bad/low battery have anything to do with the EPS malfunctioning? Today, I took the car in for a recall fix and asked this question of the service manager. He said, of course not, but to keep my fingers crossed and hope that it continues to work. So, how can a steering column that needs to be replaced, suddenly begin to work at precisely the moment there is a full electrical charge available to the car? How can there not be a connection?
Not positive on this but I wonder whether your car has one belt that drives all accessories (power steering, alternator, AC, waterpump). If so, the belt is really the one thing both your charging circuit and your power steering have in common.
I wonder whether they tightened your belt when they replace the battery and the steering problem went away. Your battery may have been good but not gotten a decent charge.