Fendt 0A.1.BD – A039 - MFA (Multifunction Armrest) / A100: Faulty linear module 4 (rocker). Valve position not functioning, lock valve.

This code indicates a fault with the 4th linear module (the fingertip rocker switch used to operate the hydraulic auxiliary valves) on the multifunction armrest. The system detects that the switch is either faulty, stuck, engaged when the ignition is turned on, or out of calibration. As a safety measure, the system locks the associated hydraulic valve.

• 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)
• Fendt 800 Vario (COM III)
• Fendt 900 Vario (COM III)

1. 1

   Visual & Mechanical Inspection: Check linear module 4 (the 4th fingertip rocker switch) for physical damage, stickiness, or debris. The switch must be able to center itself automatically under spring tension.

2. 2

   Wiring Check: Inspect the wiring harness and connectors leading to the A039/A100 multifunction armrest for pin damage or loose connections.

3. 3

   Calibration Check: Attempt to recalibrate the module before replacing parts, as loss of calibration is the most common non-hardware cause.

1. 1

   Turn on the tractor and access the diagnostic/calibration menu on the terminal.

   Ensure the switch is physically intact and moves freely before starting calibration.

2. 2

   Enter the specific calibration code for linear module 4, which is 1006.

   Input code 1006 into the terminal.

3. 3

   Step 1 of Calibration: Release the linear module so that it centers itself automatically in the neutral position.

   Press 'Return' (or OK) on the terminal to confirm this center position.

4. 4

   Step 2 of Calibration: Push the linear module forwards (do not exert excessive pressure against the spring limit).

   Hold the linear module in this forward position and press 'Return' to confirm.

5. 5

   Complete the calibration sequence as prompted by the terminal and restart the tractor.

   Follow any remaining on-screen prompts to finish calibration.

6. 6

   If the calibration fails, or if the rocker switch is physically broken/stuck internally, replace the linear module switch or the entire MFA top board.

   Replacement depends on the exact modularity of your tractor's trim level.