If your battery goes dead or if you replace your battery what settings are lost?

yes, I know the radio presets, but where do the mappings and such reside?

 

if you are running stock, then after you replace your battery, there may be a 'slight' learning period for your ecm, but that is usually not terribly noticeable.

if you have a pciii, then the map is stored in the pciii and is not affected by the battery. i would assume the fuelpack, and other aftermarket black boxes are the same, but i could not say for sure.

you would also have to reset your clock.

 

Where does the SERT or SEST store its settings, do they live in the ECM and do not get affected from the battery swap?

 

The SERT isn't affected by power loss. Not sure 'bout the SEST, but ah'm thinking it's the same.