Fendt 0A.1.B7 – A039 - MFA (Multifunction Armrest) / A100: Linear module 1 (rocker) faulty or engaged when ignition switched on.

The system registers an electrical fault or an implausible signal at startup. As a safety measure, the valve position stops functioning, and the system locks the associated hydraulic auxiliary control valve. Linear module 1 will not function.

• 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 (V/F/P)
• Fendt 300 Vario
• Fendt 400 Vario
• Fendt 700 Vario
• Fendt 800 Vario
• Fendt 900 Vario series (e.g., 916, 920, 922, 924, 926, 927, 930, 933, 936, 939, 942)

1. 1

   Check Linear Module 1 (the first fingertip rocker spool switch on the armrest) to ensure it is not physically stuck, held down by debris, or accidentally being pressed during startup

2. 2

   Ensure the rocker switch is in its neutral, centered position, then turn the tractor off completely, wait, and turn the ignition back on to see if the code clears

3. 3

   Call up the fault code on the multiple display and press the acknowledge buttons to clear the stored code from the A007 instrument panel memory

4. 4

   Attempt to run calibration code 1003 via the terminal to check if the module has lost its calibration

5. 5

   Test the A039 MFA connections (specifically connector X1401) using a 160-pin adapter box to ensure there is no wiring harness short or communication bus failure between the armrest and the basic control unit (A050)

1. 1

   Power Down

   Turn off the tractor and disconnect the battery if you are going to disassemble the armrest.

2. 2

   Clean the Module

   If the rocker switch is sticking due to dirt or spilled liquids, carefully clean the housing around Linear Module 1.

3. 3

   Recalibrate

   Power the tractor on and enter the calibration menu. Run Calibration Code 1003 for Linear Module 1. If the terminal returns an error (e.g., "F02 Calibrated values are faulty" or "F03 A039 MFA not responding"), the physical switch or the internal board is dead.

4. 4

   Replace the Component

   Disassemble the Grammer seat armrest console. Depending on the exact equipment package (Power, Power+, Profi, Profi+), the linear modules (fingertip spools) may be replaced individually or may require replacing the larger switch cluster/MFA board.

5. 5

   Final Calibration

   After installing the new linear module or armrest, you must perform Calibration Code 1003 (Linear module 1) so the basic control unit (A050) learns the new sensor's zero position and travel limits.