Fendt 05.1.32 – A039 - MFA: A039 - MFA, multifunction armrest Auto 4WD button

The Auto 4WD button has a faulty sensor, a faulty button mechanism, or a signal fault. This disables the tractor's 4WD automatic mode, leaving only the 100% 4WD manual function available.

• 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 V/F/P Vario series
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III) and 700 SCR series
• Fendt 800 Vario (COM III) and 800 S4 series
• Fendt 900 Vario (COM III) and 900 SCR series

1. 1

   Attempt to clear the fault code using the tractor's terminal or diagnostic tool to see if it is a hard fault or an intermittent glitch.

2. 2

   Inspect the Auto 4WD button on the multifunction armrest for physical damage, sticking, or debris preventing normal operation.

3. 3

   Check the wiring harness and connectors linking the A039 Multifunction Armrest to the A050 Basic Control Unit for continuity, corrosion, or pin damage.

4. 4

   Use the FENDIAS or SERDIA service diagnostics program to read the sensor values live and confirm if the button is sending a signal when pressed.

1. 1

   Power down and disconnect battery

   Power down the tractor and disconnect the battery to prevent electrical shorts during repair.

2. 2

   Disassemble armrest top cover

   Carefully disassemble the top cover of the A039 multifunction armrest to access the control panel and button matrix.

3. 3

   Inspect and replace button contact

   Inspect the specific Auto 4WD button switch contact. If the button is physically broken or the contact pad is worn out, it must be replaced.

4. 4

   Replace or repair MFA module

   If the button is integrated into the circuit board and cannot be replaced individually, the entire armrest control panel (MFA module) must be removed and replaced (or sent to a specialized agricultural electronics repair center).

5. 5

   Install and reassemble

   Install the new or repaired MFA control panel and reassemble the armrest housing.

6. 6

   Reconnect battery

   Reconnect the battery and power on the tractor.

7. 7

   Clear fault code

   Use the FENDIAS diagnostic tool to clear the 05.1.32 fault code.

8. 8

   Test Auto 4WD button

   Test the Auto 4WD button to ensure the automatic four-wheel-drive mode engages properly and the fault code does not return.