in my experience, the Autozone guys never know how to clear that properly, they just scan in a generic command. i've had to have my Lincoln mechanic do it each time i needed it. on a related topic, if the problem isn't solved and the CEL is still on, but there aren't any noticeable effects and you want it off, you can have it shut off, but it will come on again after i believe 30 engine starts. this just happened again with my recurring P0430 catalytic converter issue.