1997 Mazda 626 DX _ P1652 Code

The check engine light came on in my 1997 Mazda 626 DX 4 cylinder car with 186k miles and the code(s) came back as a P1652 Manufacturer Control, Auxiliary Inputs & Auxiliary outputs. Based on the information found on the web about this code, it is related to a "lift dive circuit". What does this mean? What is a "lift dive circuit"?

Thanks in advance for all comments & responses!