Code P2440

What is your question?

The engine light turned on like 3 years ago. I took it to have it checked at the shop and my mechanic told me not to worry about it. I have had no driving problems with my car to make me think there's something wrong. I diligently service my car at the regular intervals. Yesterday my car failed the emission test and I need to correct this problem to renew my car registration. Do you know what exactly code P2440 means and how much would it cost to fix it?