Fendt B.1.44 – A002 ECU (Enhanced Control Module): A002, A034 - ECU enhanced control / drive switch — Error counter overflow between A304 - Drive switch and Teach-in (program run).

A CAN bus communication failure (error counter overflow) between the tractor's main drive switch (the joystick) and the Variotronic Ti (Teach-in) system, which prevents the Teach-in function from operating.

• 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
• 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 300 Vario
• Fendt 400 Vario
• Fendt 700 Vario
• Fendt 800 Vario
• Fendt 900 Vario
• Fendt 916 Vario
• Fendt 920 Vario
• Fendt 924 Vario
• Fendt 926 Vario
• Fendt 930 Vario

1. 1

   Restart the tractor to see if the error clears or remains active

2. 2

   Check the power supply for the CAN bus, specifically fuses such as F047 on printed circuit board A013

3. 3

   Inspect the Enhanced control BUS wiring and connections between the A002 ECU and the A034 Drive switch for line discontinuities, corrosion, or loose pins

4. 4

   Connect the AGCO 2x4 CANUSB diagnostic scanner or FENDIAS software to read the error counter, verify A034 joystick communication status, and check for concurrent EDC/EMR or transmission bus faults

1. 1

   Power Down

   Turn off the tractor and disconnect the battery before servicing the CAN bus wiring or ECUs.

2. 2

   Harness Repair

   If the diagnostic checks reveal a broken wire or poor connection between the A002 ECU and the A034 Drive switch, repair the wiring harness or replace the damaged connector pins.

3. 3

   Component Replacement

   If the wiring and fuses are intact, the fault lies within the A034 Drive switch itself. Remove the armrest trim and replace the A034 joystick assembly.

4. 4

   Clear Codes and EOL Programming

   After replacing the joystick or repairing the harness, reconnect the battery. Use the FENDIAS diagnostic tool to clear the B.1.44 fault code. Note: Depending on the tractor's generation, installing a new joystick or ECU may require End-of-Line (EOL) programming to register the new component on the bus.

5. 5

   Operational Test

   Test the Variotronic Ti (Teach-in) functions to confirm the error counter overflow has been resolved and the system is operational.