Fendt 09.1.48 – A039 Multifunction Armrest (MFA): A039 - MFA, multifunction armrest Button, front power lift

Communication fault or electrical fault originating from the front power lift button on the multifunction armrest. When this fault is triggered, the tractor's safety protocols render the front power lift button inoperable until the next trouble-free cold start.

• 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
• Fendt 400 Vario
• Fendt 700 Vario
• Fendt 800 Vario
• Fendt 900 Vario
• 922
• 924
• 927
• 930
• 933
• 936

1. 1

   Perform a cold start reset to see if the communication fault clears

2. 2

   Inspect the front power lift button on the armrest for physical damage, sticking, or liquid/debris ingress

3. 3

   Check the wiring harness and connectors leading from the A039 MFA to the central electrical system for loose pins, chafing, or corrosion

4. 4

   Use the FENDIAS diagnostic software or a 160-pin adapter box to test the inputs and CAN bus communication of the A039 MFA

1. 1

   Power Cycle

   Shut down the tractor and restart it. If the fault code changes from "Active" to "Stored" and the button works, clear the code. If it returns, proceed to hardware troubleshooting.

2. 2

   Clean the Switch

   If the button feels sticky, use an electronics-safe contact cleaner around the edges of the front power lift button to clear any agricultural debris.

3. 3

   Check Connections

   Remove the protective covers under the multifunction armrest. Disconnect the main harness to the A039 module, inspect the pins, apply dielectric grease, and securely reconnect it.

4. 4

   Test the Module

   If the wiring is intact but the fault persists, the internal circuit board of the armrest has likely failed.

5. 5

   Replace the Component

   Depending on the specific armrest version (e.g., Power, Profi, or ProfiPlus), you may need to replace the specific keypad module or the entire A039 Multifunction Armrest assembly.

6. 6

   Reprogramming

   If the entire A039 MFA module is replaced, use FENDIAS to perform End-of-Line (EOL) programming so the A050 ECU recognizes the new armrest on the CAN bus.