Fendt A.1.18 – Electrical Valves / Spool Valves: Spool valve fault (Y015 - Auxiliary control valve, position 1)

Fault code A.1.18 is logged against component Y015 (Auxiliary control valve, position 1 - typically color-coded yellow). The code indicates a Spool valve fault where the main piston (valve actuator) cannot return to its neutral position, primarily caused by oil contamination causing the spool to stick. This is a DANGER condition, as the valve remains set, which can lead to undefined and uncontrolled hydraulic functions.

• 411 Vario COM III
• 412 Vario COM III
• 413 Vario COM III
• 414 Vario COM III
• 415 Vario COM III
• 712 Vario COM III
• 714 Vario COM III
• 716 Vario COM III
• 718 Vario COM III
• 818 Vario COM III
• 820 Vario COM III
• Fendt Farmer 400 series
• Fendt Favorit 700 series
• Fendt Favorit 900 series
• Fendt 300 Vario
• Fendt 400 Vario
• Fendt 700 Vario
• Fendt 800 Vario
• Fendt 900 Vario

1. 1

   Inspect the hydraulic oil for dirt, debris, or severe degradation, which is the root cause of the piston sticking.

2. 2

   Test the manual actuation mechanism of the Y015 valve (Valve 1 / Yellow) to ensure it has no play and returns to the neutral position by itself under spring tension.

3. 3

   Check for external debris or physical damage causing mechanical binding that prevents the valve actuator from returning to neutral.

1. 1

   Secure the Machine

   Turn off the tractor, lower all hydraulic implements to the ground, and relieve all hydraulic system pressure.

2. 2

   Locate the Valve

   Locate the central control block (often on top of the rear axle housing or under the right-hand cab steps, depending on the exact model). Identify Y015, which is the 1st auxiliary control valve (yellow).

3. 3

   Address Contamination

   Because the fault is caused by oil contamination, drain the affected hydraulic fluid, flush the system, and replace the hydraulic filters to prevent repeat failures.

4. 4

   Clean or Replace the Valve

   Remove the Y015 spool valve. Inspect the main piston and bore for scoring or trapped debris. Clean thoroughly. Re-test the slider mechanism. If the piston still binds or fails to return to the neutral position automatically, the valve block/actuator is permanently damaged and must be replaced.

5. 5

   Reassembly and Calibration

   Install the new or cleaned valve, refill the system with clean, approved hydraulic fluid (e.g., STOU SAE 5W-30/10W-40 or Fendt Extra Hyd 68), and clear the fault codes. You may need to run the EOL (End of Line) program via the FENDIAS diagnostic tool to ensure the valve is properly registered on the CAN bus.