Custom OS and OBD2 emission testing

[mistermike]

Anyone have any ideas on how OBD2 emissions testers will react to a custom O/S? Would it be recognized as the proper vehicle, or will a donnybrook ensue?

[GMPX]

I can't see why it would be a problem, unless your emmisions station looks up O.S part numbers!!

[dfe1]

The OS shouldn't be an issue, but you'll run into problems if you turn off any of the emissions tests because the PCM will never pass all the readiness tests. Instead of turning some tests off, you have to change the parameters so the test is always passed.