Check engine light - just replaced air/fuel ratio sensor but light is still on

What is your question?

I took my car (02 Toyota Camry) to the dealer & had them determine why my check engine light was on. They told me it was my air/fuel ratio sensor. I replaced the sensor but the light was still on, so we just used a pocket-scan to reset it. Was that the right way to go about it or would it have eventually reset itself? I'm worried because I need to get a smog & was told I would fail if my check engine light was on..