Fendt 08.1.47 – A039 - MFA (Multifunction Armrest) / A100 - MFA: A039 - MFA, multifunction armrest: Quick entry button, SAH rear power lift

A signal fault or faulty button has been detected on the quick entry/forced lowering button of the rear power lift, rendering the 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 (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 Vario SCR models (2011.09 onwards)

1. 1

   Perform a cold start reset by turning the ignition OFF, waiting for modules to power down completely, and turning the ignition ON to see if the fault is a temporary glitch.

2. 2

   Test the rear power lift using the external fender buttons to verify if the issue is isolated to the armrest button/signal rather than the rear EPC or hydraulic valves.

3. 3

   Perform pin-out testing on the A039 armrest using the official Fendt 160-pin adapter box to check for continuity and determine if the signal fault is internal to the switch or a wiring harness issue.

4. 4

   Clear the fault memory via the diagnostic terminal (simultaneously pressing keys D, B, and C on older Vario terminals), then press the button to see if the fault immediately returns.

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the battery to prevent electrical spikes during module removal.

2. 2

   Access the Armrest

   Disassemble the right-hand console covers to access the underside of the A039 multifunction armrest.

3. 3

   Inspect Wiring

   Check the main wiring harness and connectors plugging into the MFA for pushed pins, corrosion, or chafing.

4. 4

   Replace the Component

   If the button has suffered a hardware failure (internal short or physical breakage), replace the specific keypad module or the entire A039 armrest top console.

5. 5

   Reassembly

   Connect the new armrest/keypad to the wiring harness and reassemble the console plastics.

6. 6

   Reprogramming

   Reconnect the battery. If the entire A039/A100 MFA module was replaced, perform EOL (End of Line) programming via the FENDIAS diagnostic tool so it can properly report to the CAN bus.

7. 7

   Verification

   Turn the ignition on, clear any residual codes, and test the rear power lift quick entry button to ensure full functionality.