p1698 code 2001LXI

I have a 2001 LXI that the engine light came on.... I went to autozone last night and the salesman said it read 1698 code and it said on the diagnostic tool something like malfunction aulixary input and output.... He went inside the stote and look the code up on the computer and there was nothing referncing that code number.... So does anybody know what this means....
Also where do you look up codes at?? Any info will be help.....