Sorry, I don't have much to add that would simplify the process to that level. Are you an EE? If you work in the EE field and have the interest, you may want to track down Robert Kearney, he is the lead engineer that worked for Delphi/GMDAT during the creation of the PCM design and development for the engine management in most Aveo's (at least in the states). He was very helpful to me, and shared many key information to help discover the logic platform. Today he still works for Infineon, and he is very sharp.

FWIW: I do recall specifically he was able to confirm the CPU architecture for the MR140 modules are based on the Motorolla 68000, and the later (06-08+) MT34 is based on the Tricore TC1775 as I have shared the tech info above. I will leave it at that, for now. Good luck on your project!