Fendt A.1.43 – Electrical Valves module: Spool valve fault, valve 4 - Supply voltage > 18 volts

The system has detected an overvoltage condition at component Y018, which is the 4th auxiliary control valve. Because the voltage exceeds the safe operating threshold of 18V, the valve automatically moves into the neutral position and is locked out to prevent uncontrolled hydraulic movements or 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 (e.g., 409, 410, 411, 412)
• Favorit 700 Vario series (e.g., 711, 712, 714, 716)
• 800 Vario series
• 900 Vario series (e.g., 916, 920, 924, 926, 930)

1. 1

   Measure system voltage at the battery with the tractor running. If voltage spikes above 18V, the alternator's voltage regulator has failed and is overcharging the entire system.

2. 2

   Inspect the wiring harness leading to the Y018 (Valve 4) connector for chafing or melted wires that could be shorting the valve's power supply to a higher voltage source.

3. 3

   Disconnect the electrical plug at the Y018 valve and measure the supply voltage directly at the pins with the tractor running.

4. 4

   If the multimeter shows a normal 12-14V at the connector but the diagnostic system still reports Fault A.1.43 (>18V), the internal voltage sensor/circuit board on the Y018 valve has failed.

1. 1

   Depressurize the system

   Turn off the engine. Cycle the hydraulic controls to relieve any residual pressure in the system.

2. 2

   Disconnect power

   Disconnect the tractor's battery to prevent short circuits.

3. 3

   Remove the valve

   Disconnect the electrical connector from the Y018 valve. Remove the tie-rod bolts holding the hydraulic valve stack (manifold) together. Carefully slide out the faulty Valve 4 slice.

4. 4

   Prep the new valve

   Clean the mating surfaces on the adjacent valves. Always install brand new O-rings between the valve slices to prevent internal/external hydraulic leaks.

5. 5

   Install and torque

   Insert the new Y018 valve slice, reinsert the tie-rod bolts, and torque them to the manufacturer's exact specifications (uneven torque can cause the spool to bind).

6. 6

   Re-calibration

   Reconnect the battery and the electrical plug. Connect the FENDIAS diagnostic tool to perform an End-of-Line (EOL) programming or valve calibration so the tractor's ECU recognizes the new valve on the CAN bus.