Fendt A.1.49 – Enhanced Control ECU: Spool valve fault, valve 4

The main piston of the spool valve cannot return to its neutral position when switched on because of oil contamination. As a consequence, the valve either remains deflected or is forced into a neutral position by the system to prevent uncontrolled hydraulic functions.

• 409 Vario
• 410 Vario
• 411 Vario
• 412 Vario
• 711 Vario
• 712 Vario
• 714 Vario
• 715 Vario
• 716 Vario
• 717 Vario
• 718 Vario
• 916 Vario
• 920 Vario
• 924 Vario
• 926 Vario
• 930 Vario
• Farmer 400 series
• Favorit 700 series
• Favorit 900 series
• Fendt 300 Vario
• Fendt 400 Vario
• Fendt 700 Vario
• Fendt 800 Vario
• Fendt 900 Vario

1. 1

   Inspect hydraulic fluid for visible dirt, metal shavings, or severe degradation, as the code explicitly points to oil contamination.

2. 2

   Check hydraulic oil temperature to ensure it is at operating temperature (cold/thick oil can cause sluggish piston return and trigger similar faults).

3. 3

   Test hydraulic control pressure at test port M5 (test diaphragm accumulator) to verify it meets the 22 bar specification (test RV7/FP).

4. 4

   Verify electrical supply voltage to valve Y018 to ensure it is not exceeding 18 volts, which can cause erratic valve behavior.

1. 1

   Drain and Flush

   If the hydraulic oil is contaminated, drain the hydraulic system.

2. 2

   Filter Replacement

   Replace the hydraulic oil filters to ensure no residual debris circulates back into the valve block.

3. 3

   Refill Fluid

   Refill the system with approved hydraulic fluid (STOU SAE 5W-30, 5W-40, 10W-30, 10W-40, 15W-30, 15W-40, or engine oil HD-SAE 5W-30/10W-40).

4. 4

   Valve Cleaning/Replacement

   Locate the Y018 Auxiliary Control Valve (Valve 4, green) on the central control block. Remove the valve and inspect the main piston. If it cannot be thoroughly cleaned of the contamination causing it to stick, the valve must be replaced.

5. 5

   EOL Programming

   If a new Y018 auxiliary control valve is installed, it must be programmed for its specific position (position 4) using the Fendt EOL (End-of-Line) diagnostic software program.