My engine check light was on for couple of weeks, and I asked the dealer to run diagnostic test. It turns out to be the 02 sensor Code. I want to ask what does this code mean and how much it costs to fix it and what will be the impact if I don't fix it right the way?

Is this still under Honda manufacture's warranty. It is 1996 honda accord with 79000 Miles

 

I had to have mine replaced... it was about 200 CAD. ~ 135 USD I guess