Fendt A.1.48 – Electrical Valves (E-box) / A002 - ECU, enhanced control: Spool valve fault on Valve 4 (Y018 - Auxiliary control valve)

Main piston cannot return to neutral position because of oil contamination or valve actuator does not return to neutral position. Valve remains set, which can cause undefined and uncontrolled hydraulic functions, posing a severe safety hazard.

• 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 Vario series
• Favorit 700 and 900 series
• Fendt 300, 400, 700, 800, and 900 Vario series (including COM III, SCR, and S4 generations)

1. 1

   Perform a manual actuation test: manual actuation of the valve must not have any play, and the slider must return to the middle (neutral) position entirely by itself

2. 2

   Check the hydraulic oil for visible dirt, metal shavings, or water ingress, as oil contamination is the primary logged cause of this fault

3. 3

   Ensure no implements are attached or suspended, as the valve may be stuck in an active position causing uncontrolled movement

1. 1

   Relieve Pressure

   Turn off the tractor and relieve all hydraulic pressure from the system before servicing the valve block.

2. 2

   Inspect and Clean the Valve

   Locate the Y018 valve (Valve 4, green position) on the hydraulic block. Remove the valve and inspect the main piston/spool. If minor debris is causing the sticking, thoroughly clean the spool and valve bore.

3. 3

   Replace if Damaged

   If the spool is scored, damaged, or the actuator fails to return the piston to neutral after cleaning, the entire valve slice must be replaced.

4. 4

   Address the Root Cause (Contamination)

   Drain the contaminated hydraulic oil. Flush the hydraulic system and replace the hydraulic filters to prevent the new valve from failing. Refill with approved clean hydraulic fluid (e.g., STOU SAE 10W-40 or Fendt Super Hyd).

5. 5

   Reprogramming (EOL)

   If a new auxiliary control valve is installed, note that the valve must be programmed for its specific position (Position 4) using the Fendt EOL (End of Line) diagnostic program.