I attempted to use ECUHELP KT200 to read a Delphi E87 ECU in an Opel Mokka 1.7 CDTI via OBD but can’t write.
The file is modified dpf egr off read in bench on the table in full system but impossible to write it in bench so I try in obd I succeeded in reading but impossible to write the modified file.

Possible reason and solution:
Bad file…different size
Change your tunner
Try to do manual.checksum
Read and write on obd

BTY, for GM E87 ECU reading and writing, please better use IO Prog, which can calculate a 10-bit seed as the key.

Please refer to this video of io prog E84 ECU reading and writing which will calculate the seed as key:

Good luck!

ECUHELP KT200 and IO Prog tech support from https://www.ecuhelpshop.com/.