Fendt A.1.F1 – General System / Spool Valves / Suspension electronics: Y033 MVV - "Flush valve" solenoid — 12V supply fault

This code indicates a 12-volt electrical actuation or supply failure to the Y033 solenoid valve, which functions as the hydraulic oil preheater (flush valve). Because the valve cannot actuate, there is no hydraulic oil heating during the start-up process for the LS (Load Sensing) pump at low ambient temperatures, resulting in reduced hydraulic operation in cold conditions.

• 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
• 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 200 V, F, P, S Vario series
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III) / Farmer 400
• Fendt 500 Vario
• Fendt 700 Vario (COM III) / Favorit 700
• Fendt 800 Vario (COM III)
• Fendt 900 Vario (COM III) / Favorit 900

1. 1

   Check the Fuseboard (A013): Verify that the overall power supply from the fuseboard is intact. If multiple codes are present alongside A.1.F1, you likely have a broader 8.5V or 12V supply failure rather than a localized solenoid issue.

2. 2

   Inspect the Wiring Harness: Trace the wiring from the Y033 solenoid back to the ECU/Fuseboard. Look for chafed wires, broken connections, or corrosion at the connector plug.

3. 3

   Test Voltage Supply: Disconnect the Y033 solenoid and use a multimeter to check for a 12V signal at the harness connector when the tractor is keyed on (especially in cold ambient conditions when the preheater is commanded on).

4. 4

   Test Solenoid Resistance: Measure the resistance across the pins of the Y033 solenoid coil. An open circuit (infinite resistance) or a dead short indicates a burned-out coil.

1. 1

   Depressurize the System

   Ensure the tractor is turned off, the implement is lowered, and hydraulic pressure is relieved.

2. 2

   Locate the Y033 Valve

   Locate the MVV flush valve solenoid on the main hydraulic spool valve block (refer to the "Suspension" or "Valves 1-4" section of your specific model's service manual).

3. 3

   Disconnect Electricals

   Unplug the wiring harness connector from the Y033 solenoid.

4. 4

   Remove the Solenoid Coil

   Remove the retaining nut or snap ring at the end of the valve stem. Slide the faulty solenoid coil off the valve cartridge. (Note: If only the coil is faulty, you do not need to remove the hydraulic valve cartridge, which prevents fluid loss).

5. 5

   Install the New Part

   Slide the new OEM solenoid coil onto the valve stem and secure it with the retaining nut/ring.

6. 6

   Reconnect and Clear Codes

   Plug the wiring harness back in. Turn on the tractor and use the Varioterminal or FENDIAS diagnostic tool to clear the stored A.1.F1 fault code.

7. 7

   Test Operation

   Start the tractor in cold conditions (if possible) to verify that the LS pump start-up sequence initiates without throwing the fault code.