Fendt 03.1.02 – A039 (or A100) MFA (Multifunction Armrest) control module: A039 - MFA, multifunction armrest

Incorrect checksum for the first 128 bytes in the EEPROM. This indicates a software or memory corruption issue within the armrest's internal memory. The multifunction armrest functions become non-operable.

• 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
• Fendt 916 Vario
• Fendt 920 Vario
• Fendt 922 Vario
• Fendt 924 Vario
• Fendt 927 Vario
• Fendt 930 Vario
• Fendt 933 Vario
• Fendt 936 Vario

1. 1

   Verify the CAN bus communication wiring between the MFA armrest controller (A039/A100) and the Basic Control Unit (A050). Look for damaged wires, loose connections, or bent pins at the armrest disconnect plugs.

2. 2

   Check for accompanying fault codes (e.g., 03.1.01 for hardware/RAM/Flash failure, or 03.1.03 for a general software error).

3. 3

   Perform a power supply test to ensure the armrest controller is receiving the correct operating voltage from the central electrical system.

1. 1

   Perform EOL Programming

   Connect the tractor to FENDIAS or SERDIA diagnostic software and re-flash/reprogram the armrest control module to resolve the EEPROM checksum error.

2. 2

   Replace MFA control module

   If EOL programming fails to write to the EEPROM, or if the fault immediately returns (indicating permanent memory failure or hardware damage), physically replace the MFA control module.

3. 3

   Calibrate new module

   If a new armrest module is installed, it must be calibrated to the tractor's Basic Control Unit via the diagnostic terminal.