Not necessarily, but possibly.

The trade off when designing the map is between NOx and fuel efficiency. Using SCR provides more headroom, but without it, you are trading mpg for grams of NOx.

So they had two maps, and a detection algorithm that recognized the EPA test cycle (throttle movements, speed, etc) and used either map 1 (EPA) OR map 2 (mpg).

What will be interesting is if the reduction in mpg with the legal map takes the vehicle down to the advertised fuel efficiency, or below. If the former, then customers have been getting a free ride of sorts, polluting more but saving on fuel. If the latter, then I see buybacks.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue