Fendt 08.1.23 – A039 - MFA (Multifunction Armrest): A039 - MFA, multifunction armrest Setpoint value potentiometer, rear power lift

This fault code indicates a signal fault or failure of the setpoint value potentiometer (depth adjustment control) for the rear power lift. The system detects that the potentiometer is sending an incorrect signal or no signal at all, restricting the rear power lift to manual 'position control' only.

• 309 Vario COM III
• 310 Vario COM III
• 311 Vario COM III
• 312 Vario COM III
• 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 & SCR)
• Fendt 800 Vario (COM III & SCR)
• Fendt 900 Vario (COM III & SCR)

1. 1

   Inspect the rear power lift rotary dial/potentiometer on the armrest for physical damage, sticking, or excessive play.

2. 2

   Open the armrest console and inspect the wiring harness and connector leading to the setpoint potentiometer. Look for pinched wires, loose pins, or corrosion.

3. 3

   Verify if the potentiometer has simply lost its calibration (a related fault code, 08.1.B2, specifically indicates that the setpoint value potentiometer is not calibrated).

4. 4

   Use the FENDIAS diagnostic tool or a multimeter to monitor the live signal voltage from the potentiometer while turning the dial. If the voltage drops out, spikes, or does not change smoothly, the potentiometer is internally faulty.

1. 1

   Preparation

   Park the tractor on a level surface, lower the rear linkage to the ground to relieve hydraulic pressure, turn off the engine, and disconnect the battery.

2. 2

   Access the Component

   Carefully remove the securing screws to open the top cover of the A039 Multifunction Armrest.

3. 3

   Removal

   Locate the rear power lift setpoint potentiometer (depth adjustment dial). Disconnect its electrical connector. Remove the retaining nut or mounting clips holding the potentiometer to the armrest housing and pull the switch out.

4. 4

   Installation

   Insert the new potentiometer into the housing, secure it with the retaining hardware, and plug in the electrical connector.

5. 5

   Reassembly

   Reinstall the armrest cover and reconnect the tractor's battery.

6. 6

   Calibration

   Turn the ignition on. You must calibrate the new potentiometer. Access the tractor's terminal calibration menu and run Calibration Code 8001 (Setpoint value potentiometer, rear power lift calibration).

7. 7

   Verification

   Clear the stored fault codes and test the rear power lift in automatic/draft modes to ensure full functionality has returned.