Ford Motor revealed Friday it's the subject of a Justice Department criminal probe.

The automaker's emissions certification process coming under scrutiny by the nation's top legal authority.

Earlier this year, Ford voluntarily revealed to regulators that there may be errors in the calculations used to translate test results into the mileage and emissions data it submitted.

Ford has hired outside experts to review its vehicle fuel economy and testing procedures after concerns were brought to light by employees.

Regulators have been cracking down on emissions cheating following the major 2015 Volkswagen scandal.

The German automaker used cheating devices to make diesel engines appear to comply with emissions standards.

In fact the automobiles were pumping out far more pollution than Volkswagen led regulators to believe.

Ford reiterated Friday that it is not using so-called defeat devices to cheat on emissions standards.