Wells Fargo, the scandal-plagued bank, is facing new regulatory scrutiny for not refunding insurance money owed to people who paid off their car loans early, according to people briefed on the inquiry.

Just last month Wells Fargo was found to have forced unneeded collision insurance on consumers who financed their car purchases. That practice, first disclosed by The New York Times, affected 800,000 customers according to an analysis commissioned by the bank. Some 274,000 people were pushed into delinquency as a result, and 25,000 cars were wrongly repossessed.

The latest inquiry, by officials at the Federal Reserve Bank of San Francisco, where the bank has its headquarters, involves a different, specialized type of insurance that is sold to consumers when they buy a car. Called guaranteed auto protection insurance, or GAP, it is intended to protect a lender against the fact that a car — the collateral for its loan — loses significant value the moment it is driven off the lot.

GAP insurance, also known as guaranteed asset protection, makes up that difference for a lender if, for instance, a car is stolen before the loan is paid off. Regular car insurance typically covers only the current market value.