[bigtech]

As I understand it, these cars were designed with a simplified system for maintaining low emissions that used fewer parts. Evidently, software can allow the system to pass the emission test but at a significant loss of power.

[BashiBazouk]

I've seen a whole bunch of theories about what the practical effect of turning on test mode all the time will do. From the engine is powerful enough that the net effect will just be lower mileage up to power, mileage and reliability will get worse and everything in between. I'm surprised the chip has not already been hacked, put into permanent test mode and the performance reported. Maybe soon.