Fendt 04.1.EA – A050 - ECU, basic control unit: Error in checksum parameter for transmission teeth number

This is a software or memory-related error where the stored parameter values for the transmission's gear teeth count do not match the expected checksum. When this code is triggered, the Tractor Management System (TMS) is deactivated until the next cold start, and the tractor is forced into a transmission emergency operating mode.

• 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 200 V/F/P Vario (207, 208, 209, 210, 211)
• Fendt 300 Vario (COM III) (309, 310, 311, 312)
• Fendt 400 Vario (COM III) (409, 410, 411, 412)
• Fendt 700 Vario (COM III) (711, 712, 714, 716)
• Fendt 800 Vario (COM III) (815, 817, 818)
• Fendt 900 Vario (COM III) (916, 920, 922, 924, 927, 930, 933, 936)

1. 1

   Cycle the power by performing a complete key-off/key-on cycle to see if the checksum error clears or returns immediately.

2. 2

   Check for associated codes (such as 04.1.E0 through 04.1.EF) using the tractor's multiple display or FENDIAS software, which indicate corrupted parameters or EEPROM/RAM faults.

3. 3

   Verify voltage supply to ensure the A050 ECU is receiving stable voltage, as voltage drops or spikes can cause memory checksum errors during operation.

1. 1

   Connect diagnostic software

   Connect the tractor to the FENDIAS diagnostic software using the AGCO CANUSB diagnostic interface.

2. 2

   Perform EOL programming

   Perform EOL (End Of Line) programming on the A050 Basic Control Unit. This procedure rewrites the correct factory parameters (including the transmission teeth number) to the ECU's memory.

3. 3

   Clear fault codes

   Clear the fault codes from the A050 memory using the diagnostic software (note: fault codes in the A050 cannot be permanently deleted via the dashboard buttons; they require FENDIAS).

4. 4

   Perform test drive

   Perform a test drive to ensure the transmission emergency mode is lifted and TMS functions normally.

5. 5

   Repair or replace ECU

   If EOL programming fails or the code immediately returns, the A050 ECU has suffered an internal EEPROM/RAM hardware failure. The unit must be removed and either sent to a specialized agricultural electronics repair facility or replaced entirely.