Falling house prices and rising repossession rates in the US are at the root of the legal action, as the official attempts to make the city a "foreclosure sanctuary".
The lawsuit aims to prevent the lender from repossessing properties within his jurisdiction, and therefore bids to prop up the local housing market.
City attorney Michael Aguirre commented: "We are asking that any additional foreclosures be stopped and that the parties come together and work out a reasonable alternative based on the values of these properties today so we can stop the spread of this foreclosure disease."
He added: "We would like to see San Diego become a foreclosure sanctuary."
Mr Aguirre is also planning lawsuits against Wachovia, Wells Fargo and Washington Mutual - banks which are also attempting to foreclose on local residents.