Fendt 0A.1.X2 – Hydraulic / Valve BUS: Undervoltage condition (where U < 8V) at one of the auxiliary control valves (spool valves)

Fault code 0A.1.X2 indicates an Undervoltage condition (where U < 8V) at one of the auxiliary control valves (spool valves). The 'X' in the code corresponds to the specific valve number that is experiencing the voltage drop. When this fault occurs, the safety protocol is triggered: the affected valve automatically moves to the neutral position and locks, disabling the hydraulic function for that specific circuit.

• 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, SCR, S4)
• Fendt 800 Vario (COM III, SCR, S4)
• Fendt 900 Vario (COM III, SCR, S4)
• 916
• 920
• 924
• 927
• 930
• 936

1. 1

   Identify the Affected Valve: Use the tractor terminal to determine which specific valve (color/position) triggered the code.

2. 2

   Voltage Test: Disconnect the electrical connector at the affected spool valve. Turn the ignition on and use a multimeter to measure the supply voltage at the harness side. It must be greater than 8V (ideally standard 12V-14V system voltage).

3. 3

   Inspect Wiring and Connectors: Check the wiring harness between the valve block and the ECU for chafing, breaks, or pinched wires. Inspect the valve connector for moisture, corrosion, or pushed-out pins.

4. 4

   Check Fuses: Inspect the fuse board (e.g., PCB A013 microfuses) for any blown fuses related to the hydraulic valve BUS.

5. 5

   Component Swap (Optional): If the wiring tests fine, temporarily swap the electrical connection with an adjacent, known-good spool valve to see if the fault code follows the valve or stays with the wiring.

1. 1

   Relieve Hydraulic Pressure

   Ensure the tractor engine is off. Lower all implements to the ground. Turn the ignition on (without starting the engine) and actuate the hydraulic controls to relieve any residual pilot and system pressure.

2. 2

   Repair Wiring/Supply

   If the diagnostic checks revealed less than 8V at the connector, repair the damaged section of the wiring harness or replace the blown fuse.

3. 3

   Replace the Valve (If faulty)

   If the voltage supply is correct but the valve still throws the undervoltage/locking code, the valve's internal solenoid/electronics have failed.

4. 4

   Remove the Faulty Valve

   Clean the area around the hydraulic control block to prevent contamination. Disconnect the electrical harness and remove the retaining bolts holding the specific spool valve slice to the block.

5. 5

   Install the New Valve

   Fit the new auxiliary control valve using new O-rings. Torque the mounting bolts to OEM specifications.

6. 6

   Reconnect and Clear Codes

   Reconnect the electrical harness. Power on the tractor, navigate to the fault code menu on the Vario terminal, and clear the stored 0A.1.X2 code.

7. 7

   Test Operation

   Start the tractor and test the hydraulic remote to ensure it deflects properly without locking out.