Fendt 06.1.B0 – A039 / A100 MFA (Multifunction Armrest): A039 - MFA, multifunction armrest REAR PTO

Initialization error on the communication driver. The CAN bus communication is restricted because the internal communication driver within the armrest that handles the Rear PTO signals has failed to initialize properly, preventing it from communicating over the tractor's CAN bus network.

• 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 and SCR)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III and SCR)
• Fendt 800 Vario (COM III and SCR)
• Fendt 900 Vario (COM III and SCR)

1. 1

   Check for secondary communication fault codes that isolate specific buttons on the armrest, such as 06.1.B5 (Neutral button), 06.1.B6 (540 speed button), or 06.1.B7 (750/540E speed button).

2. 2

   Check the CAN bus wiring and connectors between the MFA (A039/A100) and the basic control unit (A050). Specifically, inspect connector X1401 for corrosion, backed-out pins, or moisture.

3. 3

   Use the Fendt 160-pin adapter box to test the A039/A100 module's inputs and outputs as per the OEM service manual.

4. 4

   Verify if the module has lost its EOL (End of Line) programming, which can cause the armrest to stop reporting to the bus.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent electrical spikes during repair.

2. 2

   Inspect Harness

   Access the wiring harness beneath the multifunction armrest. Disconnect connector X1401 and inspect the pins. Clean with contact cleaner if necessary.

3. 3

   Test CAN Bus

   Measure the CAN bus resistance at the armrest connector to ensure the network is intact (should typically read ~60 ohms if the network is healthy).

4. 4

   Replace/Repair Armrest

   If the wiring is intact and the initialization error persists, the internal communication driver on the MFA circuit board has failed and the multifunction armrest (or its internal board) must be replaced.

5. 5

   Reprogramming

   After installing a new A039/A100 armrest, connect the FENDIAS diagnostic software and perform EOL (End of Line) programming to configure the new armrest to the tractor's A050 basic control unit.

6. 6

   Clear Codes

   Clear the 06.1.B0 fault code and test the Rear PTO functions (Neutral, 540, 750/540E) to verify the repair.