Fendt 00.0.18 – A050 - ECU, basic control unit: Bus fault, electro-hydraulic steering (EHL)

CAN bus communication failure or interruption between the tractor's core control system and the electro-hydraulic steering system, which is typically associated with the Auto-Guide automatic track guidance system.

• 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 200 V/F/P Vario series
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III) and 700 SCR series
• Fendt 800 Vario (COM III) and 800 SCR series
• Fendt 900 Vario (COM III) and 900 SCR series

1. 1

   Inspect the wiring harness and CAN bus communication lines between the A050 basic control unit and the electro-hydraulic steering (EHL) components for chafing, breaks, or corrosion.

2. 2

   Check the physical connections at the electro-hydraulic steering connection plate (APLE), the pilot pressure cut-off valve (DRVLE), and the Auto-Guide solenoid valves (specifically Y085 for pilot pressure/switch-off and Y086 for steering disconnect).

3. 3

   Connect the FENDIAS or SERDIA service diagnostics tool to read the fault log and verify if the A050 ECU is communicating properly with the rest of the tractor's bus systems.

1. 1

   Resolve Physical Wiring Issues

   Repair any broken wires, corroded pins, or short circuits found in the CAN bus lines leading to the EHL system.

2. 2

   EOL Programming

   Use the FENDIAS dealer software to re-flash or re-program the A050 basic control unit to re-establish the correct bus configuration for the electro-hydraulic steering.

3. 3

   Clear Faults

   Use the FENDIAS diagnostic tool or the tractor's onboard terminal to clear the fault code memory.

4. 4

   ECU Repair/Replacement

   If EOL programming fails and the A050 ECU is deemed internally defective (e.g., damaged EEPROM or CAN transceiver), remove the A050 ECU. It must be sent out for professional mechatronic repair or replaced with a new unit.

5. 5

   Post-Repair Calibration

   If the ECU is replaced, repaired, or reprogrammed, perform the necessary steering calibrations via the tractor's terminal, specifically the Steering angle sensor calibration (Code 2401) and the VarioGuide steering valve calibration (Code 2403).