The Consumer Financial Protection Bureau is giving four banks 15 days to explain auto loans and auto dealer interest-rate markups that appear discriminatory and violate the Equal Credit Opportunity Act, sources say. The CFPB reportedly sent letters last week to the banks, warning of potential lawsuits. The agency has oversight of banks but not auto dealers. "Auto lending is within our jurisdiction," said Richard Cordray, CFPB director. "We are examining institutions around auto lending just as we are looking at them on mortgage, credit cards, student loans."