Regular use of Automatic should not cause a smog test failure. The adapter cannot change engine operating parameters when it’s plugged into your vehicle as Automatic does not conduct any pass through programming. If, however, you use the app to clear your “Check Engine” light before a smog test, this can cause you to fail the inspection if your vehicle’s readiness monitors have not successfully run and passed their tests. Be sure to check out this related article to learn more about readiness monitors and inspections.
The mechanic performing the smog inspection will also need to access your vehicle’s OBD-II port in order to complete the testing, so for safe keeping, we recommended removing the adapter from your vehicle before taking it in for a smog inspection. To learn more about your vehicle's "Check Engine" light, check out this blog post.