Fendt 0A.1.C5 – A039 - MFA (Multifunction Armrest): A039 - MFA, multifunction armrest

Faulty MFA button (switching function). This indicates an electrical fault, signal failure, or physical malfunction of a switching button on the multifunction armrest/joystick. Consequences: No switching function is possible. The tractor will maintain the switching function that was active prior to the error occurring.

• 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) and 700 SCR
• Fendt 800 Vario (COM III) and 800 SCR
• Fendt 900 Vario (COM III) and 900 SCR

1. 1

   Inspect the buttons on the multifunction armrest and joystick for physical damage, sticking, or trapped debris that could cause a constant 'pressed' signal.

2. 2

   Test the A039 MFA using the Fendt 160-pin adapter box to verify the button's signal output.

3. 3

   Check the wiring harness and connectors (specifically connector X1401) between the A039 MFA and the central electrical system for continuity, corrosion, or pin damage.

4. 4

   Verify that the MFA is properly reporting to the CAN bus, as communication drops can sometimes trigger localized button faults.

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the battery to prevent electrical shorts during service.

2. 2

   Access the MFA

   Carefully remove the trim and housing of the multifunction armrest to access the internal switch modules and joystick base.

3. 3

   Replace the Faulty Component

   If the specific button/switch module is available as a sub-component, swap it out. If the button is integrated into the main circuit board of the joystick, the entire joystick or MFA top-panel module must be replaced.

4. 4

   Reassembly

   Reconnect all wiring harnesses (ensuring connector X1401 is seated properly) and reassemble the armrest housing.

5. 5

   Programming / Calibration

   If the entire A039 MFA module was replaced, EOL (End of Line) programming and calibration of the joystick/armrest will be required using the Fendt diagnostic terminal (FENDIAS).

6. 6

   Clear Codes

   Clear the stored 0A.1.C5 fault code from the tractor's memory and test the switching functions to confirm the repair.