error code 27 ford 7840 SL?

You have a problem with the hydraulic lift arm position sensing potentiometer which is mounted through a linkage to the R/H upper lift arm, check that the linkage to it is complete and moving freely, check the connector on the wire going to it,check the resistance between green and orange wires from the potentiometer they should read 100 to 4000 whilst moving the lever in both directions, if no fault is found the wiring to the ECU needs to be tested for continuity

Para Handy
November 2009