Fendt 09.1.C0 – Overall System/Tractor: A039 - MFA, multifunction armrest: MFA not fitted

The tractor's control system does not recognize the presence of the multifunction armrest on the CAN bus network. No auto mode is possible, and the tractor's transmission and hydraulic functions become operable only via external buttons or emergency operation modes.

• 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 series
• Fendt 400 Vario series
• Fendt 700 Vario series
• Fendt 800 Vario series
• Fendt 900 Vario series (922, 924, 927, 930, 933, 936)

1. 1

   Inspect the wiring harness and connectors between the A039 Multifunction Armrest and the A050 Basic Control Unit / CAN bus for pinched wires, corrosion, or loose pins.

2. 2

   Use a 160-pin adapter box to test the electrical integrity and signals of the A039 MFA and the A038/A050 central electrical systems.

3. 3

   Connect the FENDIAS diagnostic tool to verify the End of Line (EOL) programming to ensure the ECU recognizes that the MFA is installed.

1. 1

   Power Down

   Turn off the tractor and disconnect battery power before inspecting the armrest wiring.

2. 2

   Inspect the Harness

   Remove the necessary trim to access the wiring beneath the A039 Multifunction Armrest. Re-seat the main connector to ensure a solid connection to the control bus.

3. 3

   Test Communication

   Restore power and check if the MFA boots up and communicates with the terminal.

4. 4

   Reprogram (if necessary)

   If the wiring is intact but the code persists, use the FENDIAS dealer tool to access the A050 Basic Control Unit. Navigate to the EOL programming menu and ensure the MFA is configured as 'Fitted'.

5. 5

   Replace the MFA

   If the armrest has suffered an internal hardware failure (e.g., a failed internal bus controller) and cannot communicate with the CAN bus despite good wiring and programming, the A039 Multifunction Armrest assembly must be replaced.