When you put a programmed prom back into the ecu does the ecu need to go through a period of "re-learning" like it does if you disconnect the battery?
Curious if I should pay attention to the blm's that i should be getting later on today.

 

I open the ECM power circuit (1-pin Weatherpak near the battery positive terminal) when swapping PROMs, so when I turn the key w/ a new chip I'm seeing BLMs related directly to the software I'm running. In this case, the BLMs I see are definitely noteworthy.

It's possible to swap PROMs with the ECM powered, but then you'd have BLMs from the old software being applied (initially) to the new software's config.