John Deere 7610 won't move: code RCU 57

[slidehard98]

I have had this JD 7610 (power quad w/ left hand reverser) for about 5 yrs and occasionally it will throw RCU code 57 and not move. Replacing the associated relay in the panel on the right side of cab under console normally gets it going. I have reached the point where that's no longer working. Any insight on how to diagnosis the wiring between there and the enable solenoids/sensors or determine if one of those solenoids or sensors need to be replaced would be much appreciated.

Thanks in advance for the help.

 

[jd110]

I would test the red #672 wire. It is the same wire that starts at fuse F6 or F12 depending on your serial number and it feeds the enable pressure switch, enable relay, not neutral relay, park switch and rcu. There are splices in the harness that could possibly get corrosion or lose contact. If that wire checks good, I would change out the enable pressure sensor. Have had a few of those go bad. They usually fail in a closed state and cause code 27 instead of 57, but if they fail open, the 57 code can happen.