From the manual:-
FE83, Wire breakage/short-circuit of the steering setpoint potentiometer.
A fault has been detected at the setpoint potentiometer for the steering. This may have been caused by wire breakage or a short-circuit at the potentiometer.
The brake closes, travel is blocked.
Check the setpoint potentiometer and the wiring between the potentiometer and the steering unit. Replace the potentiometer if necessary.
This error is also issued if the flutter of the potentiometer is not in order. Adjust the flutter. If adjustment is not possible, the potentiometer must be replaced.