Fendt A.1.29 – ECU, enhanced control (A002): Spool valve fault, valve 2

The main piston of the Y016 Auxiliary Control Valve (Position 2 / Blue) cannot return to its neutral position when switched on. This condition is caused by oil contamination, which makes the spool physically jam or stick, leaving the valve set and potentially leading to uncontrolled hydraulic functions.

• 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
• Farmer 400 series
• Favorit 700 series
• Favorit 900 series
• Vario 300 series
• Vario 400 series
• Vario 500 series
• Vario 700 series
• Vario 800 series
• Vario 900 series

1. 1

   Safety Warning: Ensure the tractor is turned off, implements are lowered, and hydraulic pressure is fully relieved before inspecting to prevent uncontrolled functions.

2. 2

   Perform a manual actuation test on the Y016 (blue) valve. The actuator must not have any play and must spring back to the center (neutral) position by itself; binding indicates a mechanical jam.

3. 3

   Inspect the hydraulic fluid for contamination, including debris, metal shavings, or water intrusion.

4. 4

   Verify that the hydraulic control pressure is not dropping below 22 bar, which can cause spool travel issues.

1. 1

   Relieve System Pressure

   Turn off the engine and manually actuate the hydraulic levers/controls to release any residual accumulator and line pressure.

2. 2

   Address Contamination

   If the hydraulic oil is contaminated, drain the hydraulic fluid, flush the system, and replace the high-pressure and return hydraulic filters to prevent the new valve from suffering the same fate.

3. 3

   Remove the Faulty Valve

   Disconnect the X327 electrical connector from the Y016 valve. Unbolt the valve section from the hydraulic manifold block.

4. 4

   Install the New Valve

   Mount the replacement auxiliary control valve, ensuring all O-rings and mating surfaces are clean. Torque the mounting bolts to the specified value (e.g., 30 Nm for Bosch SB1 types).

5. 5

   EOL Programming

   Use FENDIAS diagnostic software to calibrate the new valve for its specific position (Position 2 / Blue) in the EOL (End of Line) program and clear the fault codes.