Several factors can contribute to this error:
A "Checksum error writing buffer" indicates that the data integrity check failed during the transfer of the modified file from the KESS V2 tool buffer to the vehicle's ECU. The "checksum" is a value calculated from the data block to ensure that the data has not been corrupted or altered unintentionally during transmission. If the checksum calculated by the tool does not match the checksum expected by the ECU (or the checksum embedded in the file structure), the writing process is aborted to prevent bricking the ECU. checksum error writing buffer kess v2
If errors persist on all cars, the internal SD card is likely failing. If you'd like, let me know: Several factors can contribute to this error: A