Fendt 0A.1.A0 – Electric Auxiliary Control Valves: Auxiliary Control Unit EEPROM Fault
Issue description
The electronic memory (EEPROM) inside the auxiliary control valve or the enhanced control ECU failed to save operational data (such as flow rates, timer settings, or calibration values). As a safety measure, the affected hydraulic valve automatically moves to the neutral position and locks, disabling the hydraulic function for that specific circuit.
Applies to these machines
12 machines- 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) (Models 919, 922, 924, 927, 930, 933, 936)
- Fendt Katana 65 (Forage Harvester)
Check the cause
Identify the Specific Valve: Use the tractor's terminal or FENDIAS diagnostic software to read the sub-code or identifier to see exactly which valve (e.g., Y074 Yellow or Y075 Blue) is throwing the EEPROM error.
Clear and Retest: Clear the fault code from the memory and cycle the tractor's ignition. Intermittent voltage drops can sometimes cause a temporary EEPROM write failure. If the code does not return, it may have been a glitch.
Inspect Wiring and Voltage: Check the wiring harness and the connector at the affected auxiliary control valve. Look for moisture, corrosion, or loose pins. A poor power or ground connection can interrupt the CAN bus signal or cause voltage drops during the EEPROM saving process.
Swap Test: Swap the electronic actuator head of the suspected faulty valve with a known good adjacent valve on the rear stack. If the fault code follows the moved valve, the valve's internal electronics are permanently damaged. If the fault stays in the same physical position, suspect the tractor's wiring harness or the Enhanced Control ECU (A002).
Repair steps
Depressurize the System
Ensure the tractor is turned off, the implement is lowered to the ground, and all hydraulic pressure is relieved from the system before servicing the valve stack.
Disconnect the Valve
Unplug the electrical CAN/power connector from the faulty auxiliary control valve.
Remove the Valve Slice
Unbolt the tie rods holding the rear hydraulic valve stack together. Carefully remove the faulty valve slice (or just the electronic solenoid head, depending on the exact part revision).
Install the Replacement
Insert the new OEM control valve slice, ensuring all O-rings between the valve slices are properly seated and lubricated. Torque the stack tie rods to the manufacturer's specification.
Reconnect and Program
Reconnect the electrical harness. Crucial Step: A new auxiliary control valve must be registered to the tractor's CAN bus. You must use the FENDIAS diagnostic program to perform EOL (End of Line) programming so the tractor recognizes the new valve.
Test
Start the tractor, clear any residual codes, and test the hydraulic remote for proper flow, float, and lock functions.
Parts you might need
(5)Hydraulic Valve Block Solenoid
G385950350010Electronic actuator head. Fitment varies by exact model and valve position. Verify whether you need the entire mechanical valve slice or just the electronic solenoid actuator head, as well as the specific position/color (Yellow, Blue, Red, etc.) to ensure correct flow ratings and CAN addressing.
Control Valve Assembly
ACX2528450Fitment varies by exact model and valve position. Verify whether you need the entire mechanical valve slice or just the electronic solenoid actuator head, as well as the specific position/color (Yellow, Blue, Red, etc.) to ensure correct flow ratings and CAN addressing.
Control Valve
G385860100060Fitment varies by exact model and valve position. Verify whether you need the entire mechanical valve slice or just the electronic solenoid actuator head, as well as the specific position/color (Yellow, Blue, Red, etc.) to ensure correct flow ratings and CAN addressing.
Hydraulic Valve Block
ACX289555AFitment varies by exact model and valve position. Verify whether you need the entire mechanical valve slice or just the electronic solenoid actuator head, as well as the specific position/color (Yellow, Blue, Red, etc.) to ensure correct flow ratings and CAN addressing.
Solenoid Operated Valve
G312100600110Fitment varies by exact model and valve position. Verify whether you need the entire mechanical valve slice or just the electronic solenoid actuator head, as well as the specific position/color (Yellow, Blue, Red, etc.) to ensure correct flow ratings and CAN addressing.
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