What is OBD II code P1406 and how can I fix it?

I just bought a1996 Pontiac Grand Am Gt with the 3100 V6. It has a few problems that I can fix that are easy, but and thankfully it only has one code coming up and that is P1406. I have tried to look up this code but I am getting no were quick. Can you help me figure out what this is and how I might be able to fix the problem. Thank you