Fendt 9.1.5A – A002 - ECU, enhanced control: Y019 - Auxiliary control valve / Spool valve fault

Main piston deflected too far (or Valve actuator goes too far). As a safety consequence, the system forces the valve to move into the neutral position, and the affected hydraulic function is disabled. This is often caused by oil contamination preventing the piston from returning to neutral, mechanical wear, or a failure in the pilot control actuator.

• 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 300, 400, 700, 800, and 900 Vario series (including COM III generations)

1. 1

   Check hydraulic fluid for oil contamination, which can prevent the piston from returning to neutral.

2. 2

   Manually actuate the valve to check for mechanical play and ensure it returns to the center (neutral) position by itself. Check if the pilot control actuator is jamming.

3. 3

   Check the control pressure at measurement point M5 to ensure it has not dropped below 22 bar.

4. 4

   Check the diaphragm accumulators (ASP1/2, ZSP) and the RV7/FP valve for proper capacity and function.

1. 1

   Relieve Pressure

   Safely shut down the tractor and relieve all hydraulic system pressure before servicing the valve block.

2. 2

   Inspect and Clean

   Remove the affected Y019 auxiliary control valve. Inspect the spool and main piston for scoring, debris, or oil contamination. Clean the valve block thoroughly.

3. 3

   Evaluate the Valve

   If the valve was merely jammed by debris, cleaning it and flushing the hydraulic system may resolve the issue. If the main piston is scored, the internal position sensor is faulty, or the actuator fails to center itself, the valve must be replaced.

4. 4

   Install Replacement

   Install the new or cleaned auxiliary control valve into the designated slice position (e.g., yellow, blue, red, or green).

5. 5

   Calibrate the Valve

   After repair or replacement, the valve must be calibrated using the tractor's terminal (Variotronic TI). Depending on the exact valve, run the calibration for the crossgate lever (Code 1001) or the linear modules 1–4 for hydraulic auxiliary spool valves (Codes 1003–1006).

6. 6

   Clear Codes

   Clear the fault codes from the A002 ECU using FENDIAS or the onboard terminal.