Fendt A.1.4B – ECU, enhanced control (A002 module or E-box): Spool valve fault, valve 4 — Floating position is not reached

The main piston inside the #4 auxiliary control valve (spool valve) has failed to physically reach the commanded floating position. As a safety measure, the tractor's system forces the valve to move into the neutral position.

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

1. 1

   Check for Manual Override: Verify if the floating position was set manually by the operator. If it was, the system usually logs code A.1.4C instead, which has no negative consequences.

2. 2

   Check for Oil Contamination: Contaminated hydraulic oil can cause the main piston to jam or fail to return to neutral. Ensure the oil supply is clean and meets the prescribed cleanliness standards.

3. 3

   Verify Supply Voltage: Check the voltage at the valve connector (X329). The system requires standard operating voltage; if the voltage drops below 8V (code A.1.42) or spikes above 18V (code A.1.43), the valve will default to neutral.

4. 4

   Test Control Pressure: A drop in control pressure below 22 bar can cause the main piston travel to be too short (logging code A.1.44). Test the control pressure at the diaphragm accumulator.

5. 5

   Check CAN Bus Communication: Verify the wiring on A002 CAN II Pins 4 and 5 to ensure the valve is communicating properly with the ECU.

6. 6

   Hydraulic Oil Temperature: Ensure the hydraulic oil is up to operating temperature, as cold, thick oil can impede valve movement.

1. 1

   Safety & Depressurization

   Turn off the engine. Safely depressurize the hydraulic system before proceeding. Warning: The pressure pipes of the front suspension, the central control block, and the accumulators (ASP1 and ASP2) are subject to pressures up to 200 bar even with the engine switched off.

2. 2

   Access the Valve Block

   Unscrew and remove the right entrance step, and pull the right auxiliary tank outwards to access the auxiliary control valves located on the underside of the central control block.

3. 3

   Identify Valve 4 (Y018)

   Locate the 4th valve slice in the block, which corresponds to the green auxiliary control valve.

4. 4

   Removal

   Disconnect the electrical connector (X329) and the hydraulic lines. Note: Always actuate or hold the valves on side 'A' with a spanner when loosening fittings. Actuating on the opposite side can alter the internal valve setting.

5. 5

   Cleaning / Replacement

   If the valve is jammed due to dirt, clean the control block segments internally. If the internal position sensor or magnet output stage is faulty, the valve slice must be replaced.

6. 6

   EOL Programming

   If a new valve is installed, it must be electronically registered to the tractor. Use the FENDIAS / EOL (End of Line) diagnostic program to program the new valve specifically for position 4.