I took my car in for its smog certification yesterday. I did not remove my OCC system prior to the inspection. Mine is installed above and to the right of engine bay, It is black in color with clear mesh tubing. If one were to look for it, it can be seen. If one is not looking for it, you might miss it. The technician did not see it! He did do mirrors to check underneath for exhaust alterations and he did plug into my computer to look for any negative codes, with none found. I passed and went on my merry way,.............with my OCC system in place!
It probably had a lot to do with which inspector you got. A different inspector might have seen it and taken issue with the OCC installation. Chalk it up to getting lucky. Posted via the PriusChat mobile app.
I also think that because I don't have an after market intake system or anything else, it helped. My engine compartment really looks stock.