The past week has not been a particularly pleasant one for advocates of diesel cars.

Volkswagen agreed to plead guilty to criminal counts related to its diesel-emissions cheating and pay $4.3 billion in fines, while U.S. prosecutors arrested one of the company's executives and indicted five more.

Fiat Chrysler was accused by the EPA of using software in its diesel vehicles that violates the Clean Air Act, and now the Justice Department is reportedly investigating its conduct in the matter.

DON'T MISS: Justice Department launches criminal probe of FCA diesels: report

But the U.S. government is far from the only one busy with probes related to diesel emissions.

In Europe, two automakers are now subject to diesel investigations in two separate countries.

Renault and FCA are under investigation for possible violations of emissions standards in France and the U.K., respectively, reports Reuters.

2015 Ram 1500 EcoDiesel HFE

2015 Ram 1500 EcoDiesel HFE

On Friday, U.K. Department of Transport officials said they were urgently seeking information from the U.S.Environmental Protection Agency regarding its accusation against FCA.

The EPA said Thursday that FCA failed to disclose eight separate software routines that affect diesel engines' emissions.

That failure to disclose auxiliary emission-control devices, or AECDs, is a violation of the Clean Air Act.

ALSO SEE: EPA says Ram, Jeep diesel emission software violates Clean Air Act (updated)

However, so far the EPA has not labelled any of the eight AECDs "defeat devices," as it did the software used by Volkswagen to cheat on emissions tests for seven years.

The AECDs were discovered during 2017-model-year certification of Ram 1500 pickup trucks and Jeep Grand Cherokee SUVs equipped with FCA's EcoDiesel 3.0-liter V-6.

More than 100,000 of these vehicles from past model years were sold with this engine, meaning they could also have the suspect software, the EPA said.

2015 Renault Talisman

2015 Renault Talisman

While British officials seek more information on FCA's alleged emissions cheating, French officials have begun an investigation into possible emissions-rules violations by Renault.

Renault issued a statement Friday in response to the investigation, saying that its cars are "compliant with all applicable standards," and that "Renault vehicles are not equipped with cheating software affecting anti-pollution systems."

MORE: Every diesel brand in Europe emits more than VW, says new report (Sep 2016)

French officials began testing cars randomly last year in response to the Volkswagen diesel scandal.

While no "defeat devices" were found in these sweeps, officials did say that Renault models exceeded emissions limits.

_______________________________________________

Follow GreenCarReports on Facebook and Twitter