A smog test or check is one of the most common and critical tests that states demand. They’re used to calculate how much pollution your car emits as greenhouse gases and pollutants from burning liquid dinosaurs. Each state is a little different, but the basic idea is the same: make sure you’re not driving a rattletrap that hasn’t been properly maintained.


Smog tests aren’t that bothersome if you’ve followed your vehicle’s maintenance schedule and repaired any physical damage that has happened over time. After hearing all of that, you might be asking what smog checks are and how to pass one.


What is a Smog Check?


When it comes to emissions standards and smog checks, California gets all of the attention, but the truth is that numerous states have some variation of the same car inspection scheme. A smog check is a multi-part inspection that includes the exhaust and pollution control systems of a vehicle. A visual inspection of the system and its components, a functional check to evaluate the proper operation of the system’s various parts, a check of the vehicle’s computer and diagnostics (on-board diagnostics, or OBD) systems, and a check to determine the level of emissions leaving a vehicle’s tailpipe are all part of the process in most cases.