If you live in California and run an aftermarket tune on your car, you might want to think about flashing your ECU back to stock before heading out for your biennial Smog Check. Starting July 19, 2021, testing stations will begin to check whether cars are running OEM or California Air Resources Board (CARB)-approved tunes. If your car isn’t, it’ll fail the test.
California is among the strictest regions on the planet when it comes to emissions policies, so it’s not surprising to see the BAR implement a rule that it thinks will curb emissions by preventing cars from using aftermarket tunes that could increase said emissions, no matter how negligible that increase may be. For the full story, check out this article from Road & Track.