Recently, Allpar published a story on who might have been responsible for emissions issues on VM diesel engines.  Our conclusion was that blame likely fell to VM USA, Bosch, or a firm half-owned by Volkswagen.

A new study, reported on by Bloomberg , concluded that the ultimate   blame probably lies with Bosch — though FCA US signed off and took responsibility. This study looked at leaked documents from Bosch, posted on a DIY repair site. (Bosch would not confirm or deny whether the documents are authentic.)

A group from the University of California (San Diego) and Ruhr-Universitat Bochum in Germany investigated the origins of the “cheats” for around a year.  The study concluded that there is "strong evidence that both defeat devices were created by Bosch and then enabled by Volkswagen and Fiat for their respective vehicles."

The study did acknowledge that the documents, which have Bosch logos and copyrights, would not be verified as coming from the company.   See the full study (PDF).

The EPA and Department of Justice did not accuse FCA of having test-detection algorithms, as Volkswagen did. Rather, they pointed to eight specific cases where the software differed from the approved/certified version, which resulted in much higher emissions of a group of molecules associated with smog formation and health problems.

VW Volkswagen diesel

The rules on emissions-control algorithms are unclear, in terms of what is allowed in the name of engine durability and performance. Once the algorithms are disclosed, the EPA judges and accepts them or negotiates changes. In this case, eight different system behaviors were different from those approved by the EPA.

The case is currently being prosecuted by the Department of Justice, but a settlement is likely, and some believe that the main target is not FCA but Bosch itself, which largely escaped scandal in the Volkswagen case.

Ram trucks with Cummins engines easily passed recertification tests. FCA’s gasoline engines, likewise, appear to be beyond reproach.