Fendt A.1.C2 – A004 Control Console: A004 - Valve locked — Key fault

The system has detected an electrical fault with the "Overall locking key" (the button used to lock the hydraulic spool valves or front power lift). This usually means the button's internal contact is stuck closed, short-circuited, or has an open circuit. The tractor's ECU disables the function for safety, resulting in "No overall locking of valves".

• 409 Vario
• 410 Vario
• 411 Vario
• 412 Vario
• 711 Vario
• 712 Vario
• 714 Vario
• 715 Vario
• 716 Vario
• 717 Vario
• 718 Vario
• 916 Vario
• 920 Vario
• 924 Vario
• 926 Vario
• 930 Vario
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III) / Farmer 400
• Fendt 700 Vario (COM III) / Favorit 700
• Fendt 800 Vario (COM III)
• Fendt 900 Vario (COM III) / Favorit 900 (Models 916, 920, 924, 926, 930)

1. 1

   Physical Inspection: Examine the A004 Control Console on the armrest. Check the "Valve lock" button for physical damage, sticking, or debris jammed around the edges of the key membrane.

2. 2

   FENDIAS Software Diagnosis: Connect the FENDIAS (or SERDIA) diagnostic tool. Navigate to the A004 console live data to monitor the button states. Verify if the "Valve locked" key is continuously reading as "Active" (stuck) or fails to register when pressed.

3. 3

   CAN Bus / Power Supply Check: Verify the CAN bus connections and power supply to the A004 console to rule out intermittent communication drops. Check the CAN bus voltage supply on fuse board A013 (specifically fuses F040 and F041).

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent electrical shorts.

2. 2

   Remove the Console

   Remove the trim pieces and mounting screws securing the A004 Control Console to the tractor's armrest.

3. 3

   Disconnect Wiring

   Carefully unplug the CAN bus and power wiring harnesses from the bottom of the console.

4. 4

   Replace or Repair

   Option A: Install a brand-new OEM A004 Control Console. Option B: Send the defective unit to an agricultural electronics specialist (e.g., Ilgenfritz Mechatronics) who can replace the internal membrane switch and test the board.

5. 5

   Reinstallation

   Connect the wiring harnesses to the new/repaired console and secure it back into the armrest.

6. 6

   Programming

   Reconnect the battery. Connect the FENDIAS diagnostic tool to clear the A.1.C2 fault code. Depending on the tractor's generation, a new A004 console may require EOL (End of Line) programming to sync with the tractor's CAN bus.

7. 7

   Test

   Start the tractor and test the overall valve locking function to ensure the fault does not return.