Fendt A.1.44 – Enhanced Control ECU (A002): Y018 - Spool valve fault, valve 4 — Main piston travel too short due to drop of control pressure below 22 bar.

The pilot/control pressure supplying the auxiliary control valve has dropped below the minimum threshold of 22 bar, preventing the main piston inside the spool valve from completing its full travel. As a safety consequence, the system forces the valve into the neutral position and disables its operation.

• 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
• Fendt Farmer 400 series
• Fendt Favorit 700 and 900 series
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III)
• Fendt 800 Vario (COM III)
• Fendt 900 Vario (COM III)

1. 1

   Check hydraulic oil temperature to ensure cold, highly viscous oil is not causing temporary pressure drops

2. 2

   Test control pressure at port M5 to verify if the pressure is dropping below 22 bar during operation

3. 3

   Test the diaphragm accumulator to see if it has lost its nitrogen charge or ruptured

4. 4

   Inspect the FP sintered-metal prefilter located in the P duct upstream of the control pressure valve

5. 5

   Inspect the RV7 end plate shutoff valve located on the lowest plate of the control valve array

1. 1

   Warm Up the Tractor

   Run the tractor until the hydraulic oil reaches normal operating temperature to rule out cold oil as the root cause. Clear the code and retest.

2. 2

   Measure Pressure

   Connect a hydraulic pressure gauge to test port M5. Actuate the valves and monitor the gauge. If the pressure dips below 22 bar, proceed to step 3.

3. 3

   Service the Filters

   Locate the FP sintered-metal prefilter in the end plate (often near the right entrance step, lowest end plate with integral valves and filters). Remove, inspect, and clean or replace the filter if it is clogged with debris.

4. 4

   Check/Replace the Accumulator

   If the filter is clean but pressure still drops during valve actuation, the diaphragm accumulator is likely faulty. Depressurize the hydraulic system and replace the diaphragm accumulator.

5. 5

   Inspect RV7

   Check the RV7 end plate shutoff valve for proper operation and ensure it is not bypassing or sticking.

6. 6

   Replace the Spool Valve (Y018)

   If the control pressure at M5 is consistently above 22 bar and the accumulator/filters are in good condition, the main piston inside the Y018 spool valve is likely jammed or mechanically failing. Replace the Y018 auxiliary control valve and recalibrate the hydraulics using the FENDIAS diagnostic tool (EOL programming).