do you have to update or reset ecu or anything elsewhen changing an o2 sensor?

 

You'll need to get the code cleared (if you have an SES, which you probably do if you're replacing and o2 sensor) at autozone or somewhere similar.

 

if you are reading this from the tsb i linked earlier then it is a ecu flash, not a reset. unplugging your negative battery terminal will reset the ecu but with that tsb, an ecu flash is recommended. i had the tsb done in which they replaced both secondary o2 sensors as well as flashed the ecu with the new update. i am sure this is optional much like the ecu flash they have for the updated maf. there is no guarantee that the new o2 sensors would not wear out prematurely like your current ones did without the update.