Power steering failure

At seemingly random times on my 2015 Hyundai Sonata SE
2.4 the power steering light (far left of the idiot lights)
comes on and the power assist stops making the steering
wheel very hard to turn. There is another light which comes
on at the same time on the far right of the line of idiot lights
which appears to refer to the traction control system.
Sometimes the condition disappears when I turn the
ignition off and on