Volkswagen is considering installing new SCR catalytic converters on thousands of 2.0-liter diesel EA 189 engines, but must first prove that the fix will work. The converters have a tank of urea-based solution that binds with exhaust to reduce emissions.
CARB rejected the proposal because it did not say how the repair would affect engine performance, vehicle emissions, and safety, according to the Wall Street Journal.
Because there is a trade-off between vehicle performance and emissions, the simplest fix — updating the software — could significantly reduce fuel-efficiency and compromise performance on the road.
The only option besides a software updates and a mechanical fix is buying back the vehicles. Bloomberg reports that VW has concluded a buyback program would be faster than fixing them.
According to CARB, illegal software on Volkswagen’s diesel vehicles have released toxic nitrogen oxides (NOx) and caused environmental harm:
“NOx emissions in California are the most important contributor to ambient ozone and a key contributor to fine particulate matter pollution, which is associated with premature death, increased hospitalizations, emergency room visits due to exacerbation of chronic heart and lung diseases, and other serious health impacts.”