We’ve pretty much all figured it out by now: every carmaker has, at one point or another, cheated the system by installing software or specific devices designed to pass emission testing.
Mercedes’ system, according to findings following an investigation that was initially reported by the German newspaper Bild am Sonntag, has an engine management function called “Slipguard” that is able to recognize when the car is tested in a laboratory. This software regulates AdBlue fluid injection helping to eliminate harmful exhaust gases. When not in application, the cars emit up to 10 times more NOx than the legal limits.
US investigators have also found that Mercedes-Benz has done what Volkswagen, FCA and a number of other manufacturers have been found guilty of.
Interestingly, and very quietly, Mercedes has backed out of diesel engine offerings in North America. At one time not so long ago, BlueTEC (CDI) diesel-equipped utility vehicles accounted for 70% of sales (GLK/GLC, ML/GLE, GL/GLS, R-Class).
This is another story that will be interesting to watch unfold.