CA Will Start Testing for ECU Tunes During Smog Checks

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.