Fendt 4.1.E8 – A002 - ECU, Enhanced Control: Equipment "Neumaier reverse drive facility" — Checksum error on clutch pedal potentiometer or clutch calibration faulty.

The tractor's control system has detected an invalid signal (checksum error) coming from the clutch pedal potentiometer located on the Neumaier reverse drive facility (a specialized factory/dealer-installed reverse driving station, also known as Neumaier-RÜFA). Alternatively, this code is triggered if the clutch calibration for the reverse drive system is missing, drifted, or faulty. When this fault is active, the tractor will typically allow continuation in emergency mode.

• 409 Vario
• 410 Vario
• 411 Vario
• 412 Vario
• 711 Vario
• 712 Vario
• 714 Vario
• 715 Vario
• 716 Vario
• 717 Vario
• 718 Vario
• 916 Vario
• 920 Vario
• 924 Vario
• 926 Vario
• 930 Vario
• Fendt 300 Vario
• Fendt 400 Vario (e.g., Farmer 400)
• Fendt 700 Vario (e.g., Favorit 700)
• Fendt 800 Vario
• Fendt 900 Vario (e.g., Favorit 900)

1. 1

   Inspect the wiring harness connecting the Neumaier reverse drive clutch pedal potentiometer to the A002 ECU for chafed wires, corrosion in the connector pins, or loose connections.

2. 2

   Verify that the potentiometer is receiving the correct 8.5 V reference voltage (often routed via the A013 circuit board/fuse 9).

3. 3

   Determine if the tractor recently had a battery replaced, an ECU flashed, or lost its memory, as this often triggers a calibration fault.

1. 1

   Attempt Calibration First

   Because the fault explicitly mentions 'clutch calibration faulty,' attempt to recalibrate the Neumaier clutch pedal before replacing hardware.

2. 2

   Access diagnostic terminal

   Access the tractor's diagnostic terminal (FENDIAS or onboard terminal).

3. 3

   Enter Calibration Code

   Enter Calibration Code '4011', which is the specific OEM calibration code for the Neumaier reversing system clutch pedal potentiometer.

4. 4

   Register pedal limits

   Follow the on-screen prompts to register the pedal's upper and lower limits.

5. 5

   Clear fault codes and test

   If the calibration completes successfully, clear the fault codes and test the reverse drive facility.

6. 6

   Replace the Potentiometer

   If the calibration fails (e.g., the terminal rejects the values or the checksum error immediately returns), the potentiometer itself has an internal fault or dead spot.

7. 7

   Remove faulty potentiometer

   Disconnect the battery. Remove the faulty potentiometer from the Neumaier reverse drive clutch pedal assembly.

8. 8

   Install new potentiometer

   Install the new potentiometer and reconnect the harness.

9. 9

   Recalibrate new sensor

   Reconnect the battery and repeat the Calibration Code '4011' procedure to teach the A002 ECU the new sensor's values.