Fendt 08.1.A3 – A050 ECU (Basic Control Unit): Y077 - EHR cut-off valve, rear (Rear power lift control valve)

"RAM_Test" failure indicating the internal Random Access Memory (RAM) test for the valve's electronic circuitry has failed. As a built-in safety mechanism, the valve automatically moves to the neutral position and locks, turning off the hydraulic pilot pressure and disabling the rear power lift.

• 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)
• Fendt 700-900 Vario SCR series

1. 1

   Perform an ignition reset by turning the tractor OFF, waiting a few seconds, and turning it back ON to clear any temporary electronic glitches.

2. 2

   Use a diagnostic tool (such as FENDIAS or TEXA Navigator) to verify if the 08.1.A3 code is currently Active or Stored.

3. 3

   Inspect the CAN bus communication lines and the physical wiring harness between the A050 Basic Control Unit and the Y077 EHR rear cut-off valve for corroded pins, moisture, or chafed wires.

4. 4

   Attempt to recalibrate the EHR valves using the tractor's instrumentation terminal. Failure to calibrate indicates permanent damage to the internal electronics.

1. 1

   Depressurize the System

   Ensure the tractor is turned off, the implement is lowered to the ground, and all hydraulic pressure is relieved from the rear circuit.

2. 2

   Disconnect Electronics

   Unplug the electrical harness connector from the Y077 EHR cut-off valve.

3. 3

   Remove the Valve

   Remove the mechanical linkage/lever from the spool. Unscrew the hydraulic lines/pipes from the rear of the valve (Note: These can be tight; use a 6-point socket and breaker bar if necessary). Unbolt the valve body from the rear hydraulic block and withdraw the valve.

4. 4

   Install Replacement

   Mount the new or remanufactured Y077 valve to the block, reconnect the hydraulic lines, and reattach the electrical connector.

5. 5

   Calibrate the New Valve

   A newly installed CAN-based EHR valve must be calibrated prior to use. Using the tractor's terminal or a diagnostic tool, navigate to the EHR calibration menu and run the automated calibration sequence so the A050 ECU can learn the new valve's parameters.