I would have thought since computer thinks it's not reading any revs it's not going to adjust oil flow so ur going to have to check wiring 1st. Is the sensor lit up? It needs to be flashing every time it reads to send back to computer. If not lit up at all it's obviously not getting power to it. So either way you might have to check wiring loom out 1st. Does sensor come up in diagnostics on screen as working?
We checked the hydraulics, all good there. Voltage at the sending unit was 5 volts and the light was shining. Ended up reprogramming the pro 700 from the planter and putting it in the combine in place of a pro 600. So far so good.