Check engine light is on on a 05 VW Pat GLX. Got some codes from Autozone, any ideas as to what they mean?

Check engine light went on today, but the car feels perfectly fine. I took the car to Autozone to have them read the engine computer's data. The codes they got are P0491 and P0492. The Autozone guys said they have no idea what it is specifically. Their ECU computer hook-up did read out "secondary air system" along with the codes. But they don't know what that could mean. When I was checking the engine I also noticed that the coolant level was too low, could that be the problem? But there is a separate warning light for the coolant, and the Autozone guys said that this probably has nothing to do with coolant... Anyone know what those codes signify? Any help is appreciated. Thanks in advance.