After driving for a few miles this morning I stopped & called in to a shop; when I came back out the steering warning light was on & I had no Power Steering; after driving for a few miles the power assistance returned. When I stopped again the assistance disappeared again, but returned after a few miles. Car is not used very frequently, but the battery hasn't been a problem previously, and generally seems pretty good. Could this be a battery issue - or is it signs that my Power Steering ECU is shot?