Does anyone know what exactly the test sites are looking for once plugged into your OBD. Are they just scanning for codes or are they actually pulling data? I unfortunately live in one of the two counties in the entire state of Indiana where emissions tests are required. I’d love to go with catless down pipes but i just don’t think I’d be able to get away with it. I’m not even 100% sure a tune will pass. However, since all they do is plug into your OBD as far as I know they are just checking for engine codes. ...as far as I know. Because if that was the case the tune accounting for the pipes wouldn’t throw a code. Anyone with any insight into this or stories to share would be appreciated.