Fendt 09.1.46 – A039 Multifunction Armrest (MFA): A039 (or A100) - MFA, multifunction armrest. Control button, quick lift, front power lift

The system has detected a signal fault or a faulty button specifically related to the front power lift quick lift control on the multifunction armrest. The affected button is rendered inoperable by the system for safety 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 (COM III / SCR)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III / SCR / Gen series)
• Fendt 800 Vario (COM III / S4)
• Fendt 900 Vario (COM III / SCR / S4)

1. 1

   Check the front power lift quick lift button on the armrest for physical damage, sticking, or accumulated dirt/debris that might be holding the button down.

2. 2

   Turn the tractor completely off, wait a few moments, and perform a cold start to see if the fault clears.

3. 3

   Connect the FENDIAS diagnostic tool to monitor the live signal state of the A039 MFA buttons. Check if the front power lift button is registering as permanently closed (shorted) or open.

4. 4

   Inspect the wiring harness and connectors linking the A039 MFA to the tractor's CAN bus system for loose pins or corrosion.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent electrical shorts during disassembly.

2. 2

   Clean the Switch

   If the button is mechanically sticking, use an electronics-safe contact cleaner around the edges of the button to free it from agricultural dust or sticky residue.

3. 3

   Disassemble the Armrest

   If the button is internally failed, carefully remove the casing of the A039 multifunction armrest to access the internal control panel and membrane keypads.

4. 4

   Replace the Component

   Depending on the severity of the failure and part availability, replace either the specific membrane button set/repair kit or the entire armrest comfort module.

5. 5

   Reassemble and Reset

   Reassemble the armrest housing, reconnect the battery, and perform a cold start.

6. 6

   Clear Codes

   Use the tractor's terminal or FENDIAS to confirm the fault code 09.1.46 has moved from 'active' to 'stored,' and clear the fault memory. Test the front power lift quick lift function.