The company has received subpoenas and information requests from the DoJ, SEC and state investigators.

Fiat Chrysler Automobiles has issued a warning to shareholders that it could face billions in fines if US enforcement agencies find the company guilty of cheating emissions regulations.

The automaker has received subpoenas and information requests from the Department of Justice, Securities and Exchange Commission and state prosecutors offices, according to a Detroit News report.

"We are investigating these matters and we intend to cooperate with all valid governmental requests," the company said in a statement.

The company has denied that it installed an illegal 'defeat' device to trick emissions lab tests, but the Environmental Protection Agency insists some vehicles were sold with undisclosed control devices that, in some cases, appear to reduce emissions output levels during the type of conditions that are experienced in a compliance test.

If the allegations are upheld, fines could potentially reach higher than $44,500 for each affected vehicle. In total, FCA suggested a worst-case scenario could bring $4.6 billion in fines.

"EPA employs a civil penalty policy that takes into account cooperation and the degree to which emissions standards are exceeded, which we believe should reduce substantially any penalty the agencies may seek to impose from the statutory maximum," the company added.