Ok Sam, considering your engine was run recently I can eliminate the possibility that your pump was slightly stuck. You mentioned on your test that it wasn't working below 0.6V, is the line disconnected?

About the sequence process, what are the readings shown on your GSU? Did you got acceleration delay? If you got no over temp alarm and the pump won't kick in, you have to check parameter setpoint like temp and rpm required to start the pump on. Also the computer will display the reason for shutdown, did you got time out?