Fendt 06.1.97 – A039 - MFA (Multifunction Armrest) / A100 - MFA: A039 - MFA, multifunction armrest Button 750, REAR PTO - Counter error / EOL programming

The system has detected an electrical or mechanical fault with the Rear PTO 750 rpm speed preselection button (or 540E button). This is often triggered if the button is mechanically stuck, pressed for more than 30 seconds, or if the module has lost its calibration and requires End of Line (EOL) programming.

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

1. 1

   Visually and mechanically inspect the Rear PTO 750 (or 540E) button to ensure it is not jammed, sticky with debris, or held down.

2. 2

   Test the A039 MFA using the Fendt 160-pin adapter box to verify electrical continuity and check for short circuits in the keypad membrane.

3. 3

   Connect the FENDIAS diagnostic tool to check if the fault is currently active or stored, and verify MFA communication on the CAN bus.

1. 1

   Free the Button

   If the button is physically stuck due to dirt or a worn spring, carefully clean around the membrane/switch. If it pops back out, clear the code using FENDIAS and test the PTO operation.

2. 2

   Replace the Keypad/Armrest

   If the button has failed internally (electrical short or broken contact), the membrane keypad or the multifunction armrest assembly must be replaced. Disconnect the battery, remove the armrest covers, unplug the X1401 wiring harness connector to the A039 MFA, and swap the faulty component.

3. 3

   EOL Programming

   Use the FENDIAS diagnostic software to perform End of Line (EOL) programming on the A039 module.

4. 4

   Final Testing

   Start the tractor and attempt to engage the Rear PTO at the 750 rpm setting to ensure the fault code does not return and the PTO engages normally.