Koolau
Give me a museum and I'll fill it. (Picasso) Give me a forum ...
How is that different from not having the codes?
If you are going to say "Why fix something if you can't detect any problem with the performance of the car?", there is a simple answer - "The Environment".
-ERD50
I agree that the environment is important. Having said that, I faced several hundred dollars worth of diagnostic tests and possibly hundreds more in fixing whatever was actually "wrong" with no guarantee that I would be helping the environment. Heck, there was no guarantee that ANYTHING was wrong. I know when a car is not functioning properly (gas mileage drops, it "smells" like poorly burned fuel, I can smell raw fuel, it bucks, backfires, hesitates, etc.) My car had none of these issues. Wild guess - it was the computer giving a bad diagnostic.
Before I would have invested big money in chasing a possible spook, I would have considered going to a shop which could check my emissions. I honestly didn't think I needed that or I would have done it. I guess we all have our priorities in this life. Perhaps others would have been more concerned than I was. When I go to my final reward, maybe I'll be "dinged" for this indiscretion - and maybe not.
As always, YMMV.