JOHN DEERE 319D aux hydraulics not working

[Firescooby]

Machine is a hand/foot control machine.

I bought this machine used, never used aux hydraulics before on it. Borrowed a trencher and they will not work.

I've got the following codes:
AUX HYD EXTEND OUTPUT OUT OF RANGE LOW
AUX HYD EXTEND OUTPUT OUT OF RANGE HIGH
AUX HYD RETRACT OUTPUT OUT OF RANGE LOW
ENGINE OIL PRESSURE OUT OF RANGE HIGH
FUEL PRESSURE SENSOR OUT OF RANGE LOW

Where and what to start checking?

 

[koko]

If you plan on keeping the machine, the first place that I would start would be to purchase a shop manual for it. Sorry, I know nothing about deere's.