A day after the EPA announced their probe of Fiat Chrysler's alleged "cheating" over diesel emissions tests, the company now faces criminal charges as the US department of Justice has joined the probe.

As Bloomberg reports, Fiat Chrysler is now also under investigation by the U.S. Justice Department over its alleged failure to disclose software that violated emissions standards, according to people familiar with the matter, another legal hurdle for a company already under criminal scrutiny for its sales practices.

The possibility of a criminal action over diesel emissions violations comes after the Environmental Protection Agency said on Thursday it found software in 104,000 Jeep Grand Cherokees and Ram 1500s that allowed the automaker to exceed pollution limits on the road.

The criminal investigation shows the U.S. is pressing ahead on cases of alleged efforts to rig emissions testing in the waning days of the Obama administration. It isn’t clear where the inquiry stands.

And the share price is fading back towards yesterday's lows...

(Click on image to enlarge)

The U.S. investigation of Fiat Chrysler involves fewer vehicles than VW, said one of the people, who asked not to be named because the probe is confidential. The U.S. case against VW, which led to criminal charges and $4.3 billion in penalties earlier this week, centered on VW employees’ efforts to design a system that would evade U.S. environmental testing and then conspired to cover up its use when regulators began asking about it.

Fiat Chrysler’s Chief Executive Officer Sergio Marchionne said Thursday during a call with reporters the matter "has nothing to do" with VW.  He said the software wasn’t intended to bypass emissions tests or operate differently in evaluation than in real-world use, calling such allegations “absolute nonsense.”

"We are confident that no one at FCA committed any fraud or tried not to be compliant," Marchionne said. "We may be technically deficient but not immoral. We never installed any defeat device."

Marchionne told the reporters he presumed the Justice Department was also investigating.