So your information was correct, an operator thought it was a good idea to change the settings, the truck had been changed to a large frame unit with a pot, not the small frame unit with the switches, thank you for the assistance.

ok then this is not an scr controlled lift, it is contactor which means its either on or off.
What this is telling me is that there may be a setup issue possibly in the machine settings making it think there is a potentiometer or something in the settings has gone out of calibration.
If you go into the setup menu there will be a calibration routine you can run to get the system back to normal operation.
Yes even with switches the Curtis system still wants some sort of input to register settings for this function, the switch setup just has an invariable setting it registers which i supposed has changed for some reason.
do you have a service book on this unit with the calibration routines?
You'll need this to calibrate the traction and hydraulic function. Check with your local Yale dealer and see if they can get this information for you, they might sell you the service book for a nominal fee.

We had the handle apart and there were 2 micro switches for lift and lower, didn't see a pot. Is there still suppose to be a pot with the micro switches?

ok its the hydraulic pot on the control handle
code indicates pot is out of range
solution says to check wiring but besides that you should make sure it hasn't slipped, remove the thumb control button, recenter it and see if that lets it start error free. If not then the pot is probably bad and should be replaced.
If you can get into the diagnostics screen you can watch the hyd pot voltage and set it to center using those readings.

Mistake on our part, its Hyd Pot not High Pot

Are you sure about the display message?
the only ones i can find in the error code chart related to travel and lift pots are:
Throttle
Hyd Pot
Throt Lo
Throt Hi
Hyd Lo
Hyd Hi

And usually they are accompanied by a number code if you scroll the menu using the control handle