Fendt 0A.1.B6 – MFA (Multifunction Armrest) control unit (A039 or A100): Linear module 1 (rocker) not calibrated

The linear module 1 (rocker switch) on the multifunction armrest has lost its calibration parameters or a new uncalibrated module was installed. The system cannot determine the neutral or end-stop positions, causing the associated hydraulic valve to be locked out for safety.

• 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 500 Vario (e.g., S4)
• Fendt 700 Vario (e.g., SCR)
• Fendt 800 Vario
• Fendt 900 Vario (COM III, SCR, S4, Gen6)
• Fendt 1000 Vario

1. 1

   Visually and mechanically inspect the linear module 1 rocker switch to ensure it is not broken, jammed by debris, or sticking, and that it returns freely to its spring-loaded neutral center position

2. 2

   Check for operator error: ensure the operator is not resting their hand on or engaging the rocker switch while the tractor ignition is being switched on

3. 3

   Check for related MFA communication faults (e.g., F03). If the entire armrest is offline, inspect the wiring harness and connectors between the armrest controller and the tractor main ECU before condemning the rocker switch

1. 1

   Turn on the tractor's ignition and allow the terminal to boot up.

2. 2

   Access the tractor's diagnostic/calibration menu on the terminal.

3. 3

   Enter Calibration Code 1003.

   This is the specific Fendt code for calibrating linear module 1.

4. 4

   Follow the on-screen prompts to calibrate the module.

   Move the rocker switch through its full range of motion (fully forward and fully backward) so the MFA controller can learn the potentiometer's voltage values for the end stops and the neutral position.

5. 5

   Save the calibration and exit the menu.

6. 6

   Cycle the ignition, clear the fault codes, and test the operation of the auxiliary hydraulic valve.

7. 7

   If the calibration fails and throws a sub-fault (such as F02 or F08), replace the armrest operating element/comfort module, then repeat Calibration Code 1003.

   A failure indicates the internal potentiometer of the linear module has failed.