Quote from senn :

you should be able to test the voltage of that sensor, to eliminate it from the equation. I think there's specified voltages in the toyota manual, but i think you'd also need a manual oil pressure gauge to make sure actual pressure @ specified voltage is being achieved.

EDIT - i have asked the wise 3s gurus @ toymods for more info on this sender

No, come back. It's not a Toyota sensor. There isn't a Toyota electrical thing on board. We're using a Racepak sensor (with our Racepak dash). I phoned them in California last night and spoke to them. Apparently it's a firmware issue in V11 that knocks out the Vnet CANBUS. I now have V12 in my inbox ready to install!

Found the problem by turning on the dash AFTER starting the engine - and the oil pressure reading showed 82psi. But never updated. If I fired the dash before the engine then the display was frozen at 0. Similar symptom with steering position, throttle position, water temp and oil temp, all of which are on the CANBUS.

The only Toyota bits are the components that make up the mechanical parts of the engine. No sensors, gearboxes, manifolds, oil pumps etc...

But thanks for offering to look!!