Fendt 01.1.04 – A050 - ECU, basic control unit: Checksum error within the Tractor Management System (TMS)

Software data stored in the module's memory has become corrupted or does not match the expected mathematical value, preventing the TMS from operating safely. The Tractor Management System (TMS) is disabled, and the tractor will default to an emergency/manual mode where it can only be driven using the foot throttle/accelerator pedal.

• 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 (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

1. 1

   Verify symptoms by confirming that the tractor can still be driven in manual accelerator mode to isolate the issue to a TMS software/checksum fault rather than a mechanical transmission failure.

2. 2

   Check the tractor's battery voltage to ensure it is stable, as voltage drops during operation can cause EEPROM checksum errors.

3. 3

   Inspect the CAN bus connections (G-bus and K-bus) to the A050 ECU for any faults or loose connections.

4. 4

   Read active codes using the tractor's multiple display terminal to confirm 01.1.04 is active (note that it must be cleared using diagnostic software).

1. 1

   Connect diagnostic tool

   Connect the AGCO 2x4 CANUSB Diagnostic Tool to the tractor's diagnostic port (G and K bus connections).

2. 2

   Launch diagnostic software

   Launch the Fendt FENDIAS diagnostic software and open the EOL programming module (requires EOL version 7.60 or higher).

3. 3

   Establish connection

   Select 'Programming Development' and input the tractor's chassis number to establish a connection.

4. 4

   Execute EOL programming

   Execute the EOL programming procedure for the A050 Basic Control Unit to re-flash the software and correct the corrupted checksum.

5. 5

   Wait for software transfer

   Once the software transfer is complete (which can take 15-20 minutes), the system will prompt a bootloader reset.

6. 6

   Reset ignition

   Turn the Ignition OFF, wait 15 seconds, and turn the Ignition ON.

7. 7

   Clear fault codes

   Clear the stored fault codes from the A050 memory using FENDIAS.

8. 8

   Repair or replace ECU

   If EOL programming fails or the EEPROM checksum error immediately returns, the A050 basic control unit has suffered a hard internal memory failure and must be removed for specialized bench repair or replaced entirely.