Fendt 8.3.31 – Rear EPC (Electrohydraulic Power Control) ECU: Rear EPC right draft-sensing pin — Signal line fault

The system has detected a signal failure from the right-hand draft sensor pin (load pin) on the rear 3-point hitch linkage. This is typically caused by either a 9.5 V supply fault to the sensor or an internal sensor fault. It results in restricted control quality with traction control, limited electrohydraulic power lift control, and lifting/lowering may only be possible via external buttons.

• 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
• 411 Vario COM III
• 412 Vario COM III
• 413 Vario COM III
• 414 Vario COM III
• 415 Vario COM III
• 712 Vario COM III
• 714 Vario COM III
• 716 Vario COM III
• 718 Vario COM III
• 818 Vario COM III
• 820 Vario COM III
• Fendt Farmer 400 series
• Fendt Favorit 700 and 900 series
• Fendt Vario 300, 400, 700, 800, and 900 series (including COM III and S4 generations)

1. 1

   Inspect the wiring harness and the connector at the right draft-sensing pin (B031) on the rear lower link arm for broken wires, corrosion, or moisture ingress.

2. 2

   Probe the sensor connector with a multimeter to verify the reference voltage (typically a 9.5 V supply fault is flagged, though some models may specify 8.5 VDC).

3. 3

   Check the signal line for continuity between the B031 sensor connector and the Rear EPC control module.

4. 4

   Test the signal line for a short to ground or a short to power.

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the battery to prevent electrical spikes.

2. 2

   Disconnect

   Unplug the electrical connector from the right draft-sensing pin (B031) located on the rear hitch assembly.

3. 3

   Wiring Repair

   If the diagnostic checks revealed a broken wire or a 9.5 V supply issue originating from the harness, repair the wiring harness or connector terminals.

4. 4

   Sensor Replacement

   If the wiring and supply voltage are intact, the sensor itself has failed. Support the rear lower link arm to relieve tension. Remove the retaining hardware securing the right draft-sensing pin and slide the faulty pin out.

5. 5

   Installation

   Lubricate and install the new draft-sensing pin (Kraftmessbolzen). Secure it with the retaining hardware.

6. 6

   Reconnect

   Plug the electrical connector back into the new sensor.

7. 7

   Clear Codes & Calibrate

   Reconnect the battery. Use the FENDIAS diagnostic tool to clear the 8.3.31 fault code. Cycle the hitch position lever to allow the system to recapture the hitch position, and perform a rear EPC calibration if required by the specific model's service manual.