What drives the "output"? Is it a transitor, completing the path to ground? Maybe you could trace it down, and change the component that switches the output.

I have had this problem before, around 10 years ago or so, I cant seem to remember exactly what the fix was, but i do remember that it only did it if the car was at the top floor. I think it had to do something with a relevel, when the car would relevel, one of top floor hoistway inputs would not be correct and the pump would keep on pumping boiling the oil. Is you car always at the top floor? When we found out the problem, we could duplicate it every time. Damn, im getting old and can not recall exactly what the exact sequence was, but it would do exactly what you are saying. it was a fairly easy fix if i remember, moving a switch just a little did the trick, just dont know which switch it was. hope this will jog someones memory

I've had one on service for a while now that does something similar about once a year. The car will be on the springs, oil boiling. The thermal always get's it. I've checked bypass, added snubbers on the valve coils (someone removed them), replaced all the relays in the controller, replaced the valve, replaced slowdown rollers (those marshmellows)... I've only been there once when the motor was still running and I think it was the first time it happened. I'd like to know as well.