GM Code Location

[Alexander Wenning]

>         The checksum for gm 165 ecm. The code calulates checksum of 0009
> thur 3FFF. If ya modify anything must recal total at 0006,7. Gm 730 ecm code
> is similar
>
> Vance

I think it´s waste of time trying to find the checksum on all the different chips. Maybe 
GM does it the same way all the time but we´re busy with Bosch, Hitachi, Siemens, Delco, 
Weber Marelli and so on. It´s easier to modify the maps and find a suitable place (no code, 
no maps) to correct the checksum. E.g. if you´ve increased the values of a map, go and find 
a place next to your map where some $FF´s appear and decrease them until the checksum of the 
complete eprom is like the original one again.

Regards

Alex Wenning
wenning.motorsport at t-online.de