Fendt A.1.49 – Electrical Valves (E-box) / Spool Valves 1-4 module: Spool valve fault, valve 4 (Y018) - Main piston cannot return to neutral position when switched on because of oil contamination.

The electro-hydraulic valve actuator is physically failing to return the spool to its neutral center position after being commanded due to oil contamination. The system detects this discrepancy between the commanded position and the actual spool position, forcing the valve to remain set or locking it into a neutral state to prevent unintended hydraulic movement.

• 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: 409, 410, 411, 412
• Fendt Favorit 700 Series: 711, 712, 714, 716
• Fendt Favorit 900 Series: 916, 920, 924, 926, 930
• Fendt Vario COM III Series: 300, 400, 700, 800, and 900 Vario models

1. 1

   Check the hydraulic oil for visible signs of severe contamination, water ingress (milky appearance), or metal debris.

2. 2

   Inspect the hydraulic pressure filter and return filter. A clogged filter or bypassed debris is the primary cause of this specific code.

3. 3

   Physically inspect the Y018 (Valve 4 / Green) auxiliary control valve to see if the spool is binding.

4. 4

   Verify the CAN bus wiring and connections to the Y018 valve (Connector X329, pins 24, 26) to ensure a voltage drop or short isn't mimicking a mechanical bind.

1. 1

   Depressurize

   Turn off the tractor and relieve all hydraulic system pressure by cycling the hydraulic controls.

2. 2

   Access the Valve Block

   Depending on the model, remove the right rear wheel and metal panels, or access the central control block via the right step/auxiliary tank.

3. 3

   Remove Valve 4 (Y018)

   Locate the green-coded auxiliary control valve (Position 4) on the underside of the central control block. Disconnect the electrical harness (X329) and unbolt the valve.

4. 4

   Clean and Inspect

   Carefully disassemble and clean the spool valve. Flush out any oil contamination or debris. If the spool is scored or permanently damaged by the debris, the valve must be replaced.

5. 5

   Address the Root Cause

   Replace the hydraulic oil filters. If widespread contamination is found, perform a complete hydraulic system flush and refill with Fendt-approved fluid (e.g., Fendt Super Hyd or Extra Hyd 68).

6. 6

   Reinstall/Replace

   Install the cleaned or new Y018 valve.

7. 7

   Calibration

   If a new valve is installed, it must be registered to the tractor's CAN bus. You must perform End-of-Line (EOL) programming via the FENDIAS diagnostic tool to assign it to position 4.