Cat 314C LCR stuck in low idle mode

I have a Cat 314C LCR excavator that is stuck in low idle mode (engine will not rev up when I turn the engine speed dial).
My first thought was that the wiring from the low idle button to the computer was faulty but I have measured the resistance of the wires and examined them and they seem to be fine.
Does anyone know of a way to reset the computer so that it will exit this low-idle mode, or any other way to fix this? (Breaking the main electric circuit doesn't work)
I can rev it up with...

Cat 314C LCR stuck in low idle mode

Cat 314C LCR stuck in low idle mode