Fendt 0F.1.2D – A038 - Central electrical system ECU: A038 - ECU, central electrical system: Right reverse operation support valve inoperable.

The central electrical system has detected that the solenoid valve responsible for the right-side reverse drive operation support (often referred to as the "Rüfa" system in Fendt terminology) is not functioning, likely due to an open circuit, short circuit, or a failed solenoid.

• 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
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III, SCR)
• Fendt 800 Vario (COM III, S4)
• Fendt 900 Vario (COM III, S4)

1. 1

   Check the wiring harness and connectors between the A038 Central electrical system ECU and the right reverse operation support valve for open circuits, shorts to ground, or corrosion.

2. 2

   Measure the resistance/continuity of the right reverse operation support valve solenoid to verify if the coil has failed.

3. 3

   Use a Fendt adapter box or the FENDIAS diagnostic software to test the outputs of the A038 ECU to ensure the module is actually sending the signal.

4. 4

   Check for other A038 fault codes (such as 0F.1.2F for initialization errors or 0F.1.2C for the left reverse operation support valve) to rule out a broader ECU failure or CAN bus issue.

1. 1

   Power Down

   Turn off the ignition and disconnect battery power before servicing electrical components.

2. 2

   Locate the Valve

   Locate the right reverse operation support valve (Rüfa rotation solenoid valve) on the tractor's hydraulic/transmission control block.

3. 3

   Repair Wiring

   If the diagnostic checks revealed damaged wiring or a corroded connector plug at the valve or the A038 ECU harness, repair or replace the affected wiring section.

4. 4

   Replace the Valve

   If the wiring is intact but the valve solenoid failed the resistance test, remove and replace the right reverse operation support solenoid valve assembly.

5. 5

   Clear Codes

   Reconnect the battery. Use the tractor's terminal or the FENDIAS diagnostic tool to clear the stored fault codes from the A038 ECU memory.

6. 6

   Functional Test

   Start the tractor and perform a functional test of the reverse drive system to ensure the valve operates correctly and the fault does not return.