Emissions check engine light on 2013 Chevy 3500 Duramax?

how do you get a bad air filter? And there's a thing called a fuel filter that filter's diesel fuel; IF you got bad fuel the filter would catch it and a message would appear saying "water in fuel". If it was dirt and the filter was clogged you'd lose power the filter life would go to 0% and a message would come on saying change fuel filter.

It's all in the owners manual, scratch that, the diesel supplement. perhaps reading that would help