Fendt A.1.19 – Enhanced Control ECU / Electric Auxiliary Control Valves module: Spool valve fault, valve 1 — Main piston cannot return to neutral position when switched on because of oil contamination.

The main piston inside the electro-hydraulic auxiliary control valve 1 (Y015) is physically jamming or sticking due to debris or contamination in the hydraulic oil, preventing the spool from sliding back to its neutral position. This can cause the valve to remain set, leading to undefined and uncontrolled functions.

• 409 Vario
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• 715 Vario
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• 717 Vario
• 718 Vario
• 916 Vario
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• 926 Vario
• 930 Vario
• Farmer 409 Vario
• Farmer 410 Vario
• Farmer 411 Vario
• Farmer 412 Vario
• Favorit 711 Vario
• Favorit 712 Vario
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1. 1

   Inspect the hydraulic oil for visible debris, water intrusion, or metal shavings that could cause a valve to jam.

2. 2

   Check the high-pressure hydraulic filter and the return filter for excessive contamination or collapse.

3. 3

   Attempt to manually or electronically actuate Valve 1 (Y015 - Yellow) to see if it is permanently seized or if it moves intermittently.

1. 1

   Depressurize the System

   Turn off the tractor and relieve all hydraulic pressure from the system by actuating the hydraulic levers/controls.

2. 2

   Drain and Flush

   If the oil is heavily contaminated, drain the hydraulic fluid from the reservoir.

3. 3

   Remove Valve Y015

   Locate the auxiliary control valve block (usually at the rear axle housing). Identify Valve 1 (Y015, yellow). Disconnect the electrical harness (Connector X326) and remove the valve from the block.

4. 4

   Inspect and Clean

   Inspect the spool and the valve bore. If the contamination is minor, thoroughly clean the valve block and the spool. If the spool is scored, scratched, or permanently jammed, the valve cannot be repaired and must be replaced.

5. 5

   Replace Filters

   Replace all hydraulic filters (pressure and return) to ensure no residual debris enters the new valve.

6. 6

   Refill Fluid

   Refill the system with approved Fendt hydraulic fluid (e.g., Fendt Extra Hyd 68, Fendt Super Hyd, or STOU SAE 5W-30/10W-40).

7. 7

   Clear Codes

   Reconnect the battery, turn on the ignition, and use the tractor terminal or FENDIAS diagnostic tool to clear the A.1.19 fault code.