I found a document that explained this meant there was a fault in the pothole protection board.
Not knowing what that was, I then searched for "pothole board sinoboom" and found that there are limit switches which detect that these little side-plates which swing out as the lift goes up have actually deployed. The board wasn't seeing that switch input.
So, I figured out where that switch was and discovered it was sticking. I exercised it a bit and the lift was fixed.