Disabled Access Credit Expansion Act This bill amends the Internal Revenue Code, with respect to the tax credit for expenditures by an eligible small business to provide access to disabled individuals, to (1) increase from $10,250 to $20,500 the annual dollar limitation for eligible access expenditures, (2) require the $20,500 limit to be adjusted for inflation after 2020, and (3) increase from $1 million to $2.5 million the gross receipts limitation for an eligible small business. The bill also requires the Department of Justice (DOJ) to carry out an ADA Mediation Program to (1) facilitate voluntary mediation to resolve disputes arising under the Americans with Disabilities Act of 1990, and (2) train mediators who provide services through the program. DOJ may hire or enter into contracts with personnel for the program. DOJ must also report to Congress on the ADA Information Line, which is a toll-free line operated by DOJ to provide information and materials to the public about the requirements of the Americans with Disabilities Act of 1990.