Fendt 0A.1.C1 – A039 / A050: MFA GD fault in button used by hydraulics

A button on the multifunction armrest (MFA) responsible for controlling a hydraulic function is sending an erroneous, continuous, or faulty signal. As a safety consequence, the basic control unit locks the hydraulic valve to prevent unintended operation.

• 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 200 Vario (207, 208, 209, 210, 211)
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III) (409, 410, 411, 412)
• Fendt 700 Vario (COM III) (711, 712, 714, 716)
• Fendt 800 Vario (COM III) (815, 817, 818)
• Fendt 900 Vario (COM III) (916, 920, 922, 924, 926, 927, 930, 933, 936)

1. 1

   Inspect the hydraulic control buttons on the A039 Multifunction Armrest (MFA) for physical damage, sticking, or debris (most common cause).

2. 2

   Check the CAN bus communication and wiring harness connections between the A039 MFA and the A050 basic control unit ECU. Look for pinched wires or loose connectors under the armrest.

3. 3

   Use the tractor's terminal or FENDIAS diagnostic software to monitor the live states of the MFA buttons to identify exactly which hydraulic button is stuck in the 'pressed' state.

1. 1

   Turn off the tractor ignition and disconnect the battery if you plan to perform electrical work or replace modules.

   Turn off the tractor ignition and disconnect the battery if you plan to perform electrical work or replace modules.

2. 2

   Thoroughly clean the multifunction armrest, specifically targeting the hydraulic control buttons.

   Use compressed air or a plastic-safe electronic contact cleaner to dislodge any dirt or debris causing the button to stick mechanically.

3. 3

   Test the button's mechanical action.

   If the button remains internally shorted or physically broken after cleaning, the A039 multifunction armrest (or the specific modular keypad/joystick, depending on the exact tractor model's configuration) must be replaced.

4. 4

   If replacing the unit, disconnect the wiring harness from the old armrest, unbolt the console, and install the new OEM replacement part.

   If replacing the unit, disconnect the wiring harness from the old armrest, unbolt the console, and install the new OEM replacement part.

5. 5

   Reconnect the battery and turn on the ignition.

   Reconnect the battery and turn on the ignition.

6. 6

   Use the tractor's terminal or FENDIAS diagnostic software to clear the stored 0A.1.C1 fault code.

   Use the tractor's terminal or FENDIAS diagnostic software to clear the stored 0A.1.C1 fault code.

7. 7

   Test the hydraulic functions to ensure the valve is no longer locked and operates normally.

   Test the hydraulic functions to ensure the valve is no longer locked and operates normally.