Fendt A.1.C2 – A004 - ECU, control panel: Valve locked / Overall locking key faulty.

This code indicates a 'Key fault' regarding the spool valve operation. Specifically, the system detects a malfunction with the 'Overall locking key' (the button used to lock the hydraulic spool valves). The system registers the button as defective, stuck, or experiencing an electrical short, which results in the tractor disabling the overall locking function of the valves.

• 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
• Fendt Farmer 400 Vario
• Fendt Favorit 700 Vario
• Fendt Favorit 900 Vario
• Fendt 900 Vario COM III (Models 916, 920, 924, 926, 930)
• Fendt 300 and 800 Vario series (COM III)

1. 1

   Inspect the overall locking key on the A004 control console for physical damage, sticky residue, or debris that might be causing the button to mechanically stick in the depressed position.

2. 2

   Verify the voltage supply and CAN bus connections to the A004 control console. Check fuses F040 and F041 on printed circuit board A013.

3. 3

   Connect the FENDIAS diagnostic tool to monitor the live state of the switch. If the switch state does not change when pressed, the internal contact or the console's internal board (RAM/EEPROM) has failed.

1. 1

   Clean console face

   If the button is mechanically stuck due to dirt, a thorough cleaning of the console face may resolve the issue.

2. 2

   Power down

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

3. 3

   Remove the console

   Carefully pry or unscrew the retaining trim around the A004 Side Console on the right-hand armrest/fender area.

4. 4

   Disconnect wiring

   Disconnect the multi-pin connectors and CAN bus harnesses from the bottom of the A004 ECU.

5. 5

   Install new module

   Connect the wiring harnesses to the replacement A004 control console and seat it back into the armrest housing.

6. 6

   Calibration / Teach-in

   Reconnect the battery. Because a new control console (A004) has been introduced to the CAN network, you may need to perform a 'Teach-in' (program run) via the Variotronic TI system to calibrate the hydraulic auxiliary control valves and ensure the new module communicates properly with the A002 (Enhanced Control ECU).

7. 7

   Clear codes

   Clear the A.1.C2 fault code and test the overall locking key to ensure the spool valves lock and unlock correctly.