Fendt 0A.1.B5 – A039 / A100 (MFA): MFA, multifunction armrest - Joystick centre position recognition faulty

Joystick centre position recognition faulty (electrical fault) or the joystick was engaged (moved out of the neutral position) when the ignition was switched on. As a consequence, the system locks the valves for safety.

• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III)
• Fendt 800 Vario (COM III)
• Fendt 900 Vario (COM III)
• Fendt 700-900 SCR models

1. 1

   Check for operator error: ensure the joystick was not held or stuck out of the center position when the tractor was started.

2. 2

   Physically inspect the joystick to ensure it returns to the dead-center neutral position and is free of debris or obstructions.

3. 3

   Inspect the wiring harness and connector X1401 (routing to the A039 MFA) for corrosion, loose pins, or damaged wires.

4. 4

   Test the joystick center position recognition sensor/switch for electrical continuity and proper voltage supply.

1. 1

   Reset the System

   Turn off the tractor ignition completely. Ensure the joystick is completely free of obstructions and sits in the neutral position. Turn the ignition back on without touching the joystick. If the code clears, no further repair is needed.

2. 2

   Inspect Connections

   If the code remains active, access the A039 Multifunction Armrest module. Disconnect and inspect connector X1401. Clean the contacts with electrical contact cleaner and reconnect securely.

3. 3

   Test the Joystick

   Using a multimeter or FENDIAS diagnostic software, verify if the center position switch is sending the correct neutral signal to the MFA.

4. 4

   Replace the Component

   If the joystick's internal center position sensor has failed electrically, the joystick unit (or the affected linear rocker module) must be replaced.

5. 5

   Calibration / EOL Programming

   After replacing the joystick or MFA components, perform a calibration procedure (Calibration code '1003' is often required for linear modules on the MFA) or End-of-Line (EOL) programming using the FENDIAS tool so the tractor recognizes the new center values.