We’ve suspected for some time that more automakers would be caught up in the Volkswagen emissions cheating scandal, and the first new perpetrator has apparently been identified: General Motors. GM CEO Mary Barra’s insists that VW-style software cheating on emissions tests “is not a condition that exists in our vehicles,” but the German environmental group Umwelthilfe has sponsored tests that throw that claim into serious doubt [English press release in PDF format here].
In testing of the Opel Zafira 1.6 CDTi, performed at the Bern University of Applied Sciences, GM’s diesel engine passed NEDC cycle NOx tests performed on a two-wheel (single-axle) rolling road but emitted two to four times the Euro6 limit for NOx when the same test was performed on a four-wheel rolling road. This strongly indicates that a software “test mode” exists for this engine, although Opel insists that “The software developed by GM does not contain any features that can detect whether the vehicle is being subjected to an emissions test.” But, says International Transport Advisor Axel Friedrich, “I have no normal, technically plausible explanation for the emission behavior of the Opel vehicle.”
