Hi Juma,

FE06, Travel transducer already actuated when the vehicle is switched
on or travel transducer actuated without deadman switch. If a "travel setpoint" signal (U>5.5V) from the travel transducer 1U20 is already detected
when the vehicle is switched on, before the main contactor K1 closes, or if the travel transducer is actuated before the deadman switch 1S25 (incorrect operating sequence), the travel function is blocked.
Check travel transducer 1U20, deadman switch 1S25 and the wiring. Maintain the correct operating sequence.

FE07, Travel transducer switch does not close or is already closed
when the vehicle is switched on. When the FPS detects a "travel setpoint" signal (U>5.5V), the micro-switch of the travel transducer must also be closed. If it does not close, travel is not permitted.
The same error message is also issued if the micro-switch of travel transducer 1U20 is already closed during the switching-on process.
Check the travel transducer (see "Travel transducer").

FE33, Hydraulics converter internal fault. The internal safety circuit in the converter has detected a fault. The output power is
switched off. The converter must be replaced.

FE54, Potentiometer outside zero window.When the vehicle is switched on, the setpoint from the potentiometer for main lift, reaching, tilting or transverse reaching is not within the defined zero point window, i.e. a hydraulic function is already selected when the vehicle is switched on. The function in question is blocked. Check the potentiometer and replace if necessary.
Remark: The zero window can be adjusted with the service software (see "Service software").

Hope this helps.