Fendt 08.1.FA – A050 ECU: Valve actuator deflected too far

The valve moves to neutral and locks. Pilot pressure is often switched OFF as a safety measure. This is typically caused by the valve actuator mechanically jamming (in either the pilot control or main actuator) due to contamination in the hydraulic oil, or due to brief control pressure dips.

• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• FENDT 300 Vario (COM III)
• FENDT 400 Vario (COM III)
• FENDT 700 Vario (COM III)
• FENDT 800 Vario (COM III)
• FENDT 900 Vario (COM III)
• 916 Vario
• 920 Vario
• 922 Vario
• 924 Vario
• 926 Vario
• 927 Vario
• 930 Vario
• 933 Vario
• 936 Vario

1. 1

   Switch the ignition OFF and ON to see if the valve resets from its locked neutral position

2. 2

   Check hydraulic oil level and ensure the oil is not too viscous (especially in cold temperatures)

3. 3

   Inspect hydraulic filters and oil for contamination or debris, which is the primary cause of actuator jamming

4. 4

   Verify voltage supply to the valve by checking the A013 printed circuit board and fuses F040 and F041

5. 5

   Check for overvoltage (U > 18V) which can cause the valve to lock

6. 6

   Perform a passive CAN bus check (ensure terminating resistors are intact) to rule out communication loss between the Y077 valve and the A050 ECU

7. 7

   Verify there are no brief control pressure dips in the hydraulic system causing the actuator to fall short or over-deflect

1. 1

   Preparation

   Park the tractor on a level surface, lower the rear linkage to the ground to relieve mechanical tension, and turn off the engine.

2. 2

   Relieve Pressure

   Ensure all hydraulic pressure is relieved from the rear EPC system. Danger: The system can remain under high pressure even when the engine is switched off.

3. 3

   Locate the Valve

   The Y077 Rear EPC cut-off valve is located at the rear of the tractor on the rear valve block.

4. 4

   Disconnect Electricals

   Carefully unplug the electrical harness connector from the Y077 solenoid valve.

5. 5

   Remove the Valve

   Unbolt and remove the rear EHR/EPC valve from the rear end plate (EPH).

6. 6

   Inspect/Clean

   Inspect the valve spool and actuator for mechanical jamming or debris. If the valve is heavily contaminated or the internal actuator is damaged, it cannot be repaired and must be replaced.

7. 7

   Install New Valve

   Fit the replacement Y077 valve to the rear valve block using new O-rings/seals. Torque the mounting bolts to OEM specifications.

8. 8

   Reconnect and Test

   Reconnect the electrical harness. Start the tractor, check for hydraulic leaks, and test the rear power lift functionality. Clear the 08.1.FA fault code via the tractor's diagnostic terminal or SERDIA software.