Fendt 08.1.FF – A050 - ECU, Basic Control Unit: Communication or message failure on the CAN bus for Y077 EHR cut-off valve

This code indicates a communication or message failure on the CAN bus ('No setpoint message,' 'No configuration message,' or 'Setpoint message is not plausible'). As a safety measure, the valve automatically moves to neutral and locks, and the pilot pressure is turned OFF, disabling the rear power lift/hydraulics.

• 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)
• FENDT 800 Vario (COM III)
• FENDT 900 Vario (COM III)

1. 1

   Inspect the wiring harness and connectors between the A050 Basic Control Unit and the Y077 rear EHR cut-off valve for chafed wires, corrosion, or loose pins

2. 2

   Verify the integrity of the CAN bus communication lines to the valve and ensure bus ends are properly sealed with terminating resistors

3. 3

   Check the power supply (8.5V or 12V depending on pinout) and ground to the Y077 valve

4. 4

   Inspect the valve actuator for mechanical jamming or contamination in the hydraulic oil

5. 5

   Check the A050 ECU for other active internal EEPROM or RAM error codes (e.g., 08.1.A1, 08.1.A2, 08.1.A3) which indicate a control unit failure

1. 1

   Relieve Pressure

   Ensure the engine is off, the tractor is secured, and hydraulic pressure is relieved before servicing the valve block.

2. 2

   Repair Wiring

   If the diagnostic checks reveal a break or short in the CAN lines or power supply, repair the wiring harness and clear the codes.

3. 3

   Replace the Valve

   If the wiring is intact and the A050 ECU is outputting the correct signals, the internal electronics of the Y077 smart valve have likely failed. Remove the hydraulic lines and electrical connector, unbolt the Y077 valve from the rear hydraulic block, and install the replacement.

4. 4

   ECU Repair/Replacement

   If the A050 Basic Control Unit is found to be the culprit (failing to send messages), it must be sent out for mechatronic repair or replaced.

5. 5

   EOL Programming

   Replacing either the Y077 valve or the A050 ECU will likely require End-of-Line (EOL) programming and calibration using the FENDIAS diagnostic software so the ECU recognizes the new valve's configuration.