What is a Smog Check?

As a response to increasing amounts of air pollution, states began passing legislation that required periodic inspection of vehicles’ emission control systems. Vehicles with improperly operating emission controls are required to bring them into compliance with these laws. The laws regulate the amount of pollutants that can be present in a vehicle’s emissions, before they can continue operation. In order to conduct these checks, the state authorizes certain repair facilities to inspect and test vehicles, issuing certification of compliance or notification of failure.

What is a Smog Check?

A smog check consists of a series of tests that confirm the type and amounts of pollutants contained within a vehicle’s exhaust. Tests have both a visual and functional aspect to the inspection.  A qualified technician physically inspects the exhaust pipes, gas cap, and gauge cluster. The technician looks for holes caused by rust, bad seals, or damage from debris that may interfere with the exhaust’s normal operation. They confirm that the gas cap makes a proper seal on the tank, which allows the onboard emission controls to function properly. The technician inspects the gauges to see if the check engine or other warning light indicates that the vehicle’s diagnostics have detected a problem.

How to Get a Smog Check

Arrange for your vehicle to receive a smog check by contacting a designated facility near you. When scheduling, confirm whether the facility only does the testing and issuing of a pass or fail certification, or if they are an “inspect and repair” facility.  If you take your vehicle to a facility that offers both testing and certification, and conducts repairs, be sure it has a reputation for honesty and quality work.

What Happens if a Vehicle Doesn’t Pass a Smog Check?

If your vehicle doesn’t pass testing, you’ll be issued a report that explains the reasons. This isn’t necessarily a diagnosis of what is wrong with the vehicle. You’ll need to have a technician diagnose the underlying issue. Use your copy of the emissions report to assist the technician in their efforts to conduct a repair. After the repair is made, the vehicle retested until the emissions are compliant within the state’s limits.

How to Pass a Smog Check

There are a few simple steps you can take to increase your odds of passing a smog check. If your vehicle’s check engine light is on, make an appointment with a repair facility to have the underlying issue addressed. A check engine warning light is an automatic fail.  Ensure your gas cap is tightened, too. A loose cap can interfere with the normal operation of the emissions system, and trigger the check engine light. Finally, operate the vehicle at highway speeds for more than just a short trip.  This allows the catalytic converter to reach the correct temperature.

While it seems daunting, having a smog check needn’t be intimidating. Repairs can be made, and the end result is a car that complies with state laws and doesn’t pollute the environment.