Fendt A.1.25 – Tractor Main ECU / Hydraulic Control Module: Spool valve fault (typically valve 2 or 3) - Overvoltage condition (> 45 volts)

When the system detects a voltage spike exceeding 45V at the auxiliary control valve (Y016), the safety protocol is triggered, and the valve automatically moves into the neutral position to prevent uncontrolled hydraulic movements or further electrical damage.

• 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
• Farmer 400 Vario Series: 409, 410, 411, 412, 413, 414, 415
• Favorit 700 / 700 Vario Series: 711, 712, 714, 716, 718, 720, 722, 724 (including SCR and S4 variants)
• Favorit 900 / 900 Vario Series: 916, 920, 922, 924, 926, 927, 930, 933, 936, 939 (including TMS, SCR, and S4 variants)
• 800 Vario Series: 815, 817, 818, 820

1. 1

   Test the tractor's overall charging system (alternator and voltage regulator) for system-wide voltage spikes.

2. 2

   Inspect the wiring harness leading to the Y016 auxiliary control valve for chafed wires shorting to a high-voltage power source.

3. 3

   Disconnect the harness at the valve and use a multimeter to check the voltage at the connector pins while the tractor is running.

4. 4

   Swap the electrical connector of the suspect valve (Y016) with an adjacent, known-good spool valve to isolate whether the fault is in the wiring or the valve's internal electronics.

1. 1

   Depressurize the System

   Turn off the tractor, lower all implements to the ground, and cycle the hydraulic controls to relieve residual hydraulic pressure.

2. 2

   Disconnect Power

   Disconnect the tractor's battery to prevent further electrical shorts during repair.

3. 3

   Remove the Valve

   Disconnect the electrical harness from the Y016 spool valve. Unbolt the hydraulic lines and quick-release couplings, catching any residual hydraulic fluid in a drain pan.

4. 4

   Replace the Component

   Depending on the diagnosis, replace either the specific solenoid coil or the entire directional spool valve assembly.

5. 5

   Reinstall and Bleed

   Bolt the new valve into the hydraulic block, reconnect the hydraulic lines, and plug in the electrical harness.

6. 6

   Calibration

   Reconnect the battery. Start the tractor and use the FENDIAS diagnostic software or the tractor's terminal to clear the A.1.25 fault code and calibrate the new spool valve's neutral position.