Originally Posted by greenpower
so this means that if i have an early software in the ecu, and i make changes in the catalizer, my ecu will be fried? because in my shop there's a 2002 doing o2 sensors and cat, but still with creepy emissions.
The cat is also prone to failure in the earlier models specially if they didn't have the ECU updated. They came out with a software reflash to minimize this issue in the later years, which can be applied to the earlier models. Once you change the cat you will need to update the ECU to stop the cat from failing again.
The other issue (which is unrelated) is the ECU physically going bad. The symptoms for that I've listed in my other post.