Fendt 9.1.C6 - 9.1.CA – A004 - ECU, control panel: CAN-bus fault or unspecified malfunction communicating with the control console

The system cannot detect status changes from the console's inputs. As a result, engagement or disengagement commands may be overridden, and specific functions—such as lowering the front power lift—will become non-operational or restricted.

• 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
• Farmer 400 Vario series (409, 410, 411, 412)
• Favorit 700 / 800 Vario series (711, 712, 714, 716, 815, 817, 818)
• Favorit 900 Vario series (916, 920, 924, 926, 930)
• Various COM III generation Vario tractors

1. 1

   Check the voltage supply for the CAN-Bus to the A004 console by inspecting fuses F040 and F041 on the A013 fuse board.

2. 2

   Inspect the CAN-Bus wiring (Enhanced Control Bus) between the A002 (ECU, enhanced control) and the A004 (Control console) for continuity, shorts, or corrosion.

3. 3

   Verify that there is no external 8.5 V supply fault reaching the control panel.

4. 4

   Review the 'Spool valves 2' or 'FRONT POWER LIFT' circuit diagrams in the workshop manual to trace the specific signal lines related to the A004 console.

1. 1

   Disconnect Battery

   Always disconnect the tractor's battery before servicing electrical nodes to prevent short circuits.

2. 2

   Replace Fuses

   If fuses F040 or F041 on the A013 board are blown, replace them and retest the system.

3. 3

   Repair Wiring

   If the diagnostic checks reveal a break or high resistance in the CAN-bus wiring harness between the A002 and A004 ECUs, repair or replace the damaged wiring sections.

4. 4

   Remove the A004 Console

   If the wiring and power supply are intact, the A004 control console itself has likely suffered an internal hardware failure. Remove the panel (located in the cab on the right mudguard/armrest).

5. 5

   Repair or Replace

   You can either replace the A004 console with a new/remanufactured OEM part or send the defective unit to a specialized agricultural electronics repair center.

6. 6

   Reprogramming

   If a new or remanufactured A004 console is installed, connect the FENDIAS diagnostic tool to perform EOL (End of Line) programming and teach-in calibrations (Variotronic TI operation) to marry the new console to the tractor's A002 enhanced control ECU.