Fendt A.1.4A – ELECTRICAL VALVES / VALVE 4 / VENDI: Spool valve fault, valve 4 — Main piston deflected too far (or "Valve actuator goes too far")

The main spool piston inside auxiliary hydraulic control valve #4 has traveled beyond its calibrated physical limit. This is most commonly caused by hydraulic oil contamination preventing the spool from returning to the neutral position, or an internal failure of the valve's position sensor/actuator head. The system forces the valve into the neutral position as a safety measure, disabling the hydraulic function for that specific remote.

• 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 Vario (409, 410, 411, 412)
• Favorit 700 / 700 Vario (711, 712, 714, 716, 718)
• Favorit 800 / 800 Vario (815, 817, 818, 820)
• Favorit 900 / 900 Vario (916, 920, 924, 926, 930, 933, 936)
• 300 Vario (COM III)

1. 1

   Pull a hydraulic oil sample and inspect the filters for debris to check for contamination, which can prevent the spool from returning to neutral.

2. 2

   Verify the hydraulic control pressure has not dropped below 22 bar, which can cause erratic spool travel.

3. 3

   Inspect connector X329 at Valve 4 (Y018) for corrosion, moisture, or damaged pins, and verify supply voltage is between 8V and 18V.

4. 4

   Perform a swap test by exchanging the electronic head of Valve 4 with an adjacent valve (e.g., Valve 3). If the fault code changes to A.1.3A, the electronic head is faulty. If it remains A.1.4A, the mechanical spool is sticking.

1. 1

   Preparation

   Lower all hydraulic implements to the ground, relieve residual hydraulic pressure, and disconnect the tractor's battery.

2. 2

   Access the Valve Stack

   Locate the rear hydraulic spool valve block. Identify Valve 4 (Y018, green remote).

3. 3

   Remove the Electronic Head

   Disconnect the CAN/power connector (X329). Unbolt the electronic actuator head from the mechanical valve slice.

4. 4

   Inspect the Spool

   Manually actuate the mechanical spool piston. If it binds, sticks, or shows heavy scoring, the entire valve slice must be removed, cleaned, or replaced. If it moves freely, the fault is isolated to the electronic head's position sensor.

5. 5

   Replacement

   Install the new electronic spool valve head (or complete valve slice) using new O-rings. Torque the mounting bolts to OEM specifications.

6. 6

   Reassembly & Fluid Maintenance

   Reconnect connector X329. If contamination was found during diagnostics, drain the hydraulic oil and replace the hydraulic filters before operating the system.

7. 7

   EOL Programming

   Connect the FENDIAS diagnostic laptop. A new electronic valve head must be programmed via the End-of-Line (EOL) program to teach the tractor the new valve's position limits and assign it to the Valve 4 position.