The purpose of emissions testing is to improve air quality and reduce environmental impact. That’s why the Environmental Protection agency, also known as the EPA, sets a strict standard when it comes to emissions testing and why so many U.S. states follow suit to conduct these tests properly. If you are unsure if your vehicle meets the standards, then it’s best to have a professional take a closer look. Follow along in our blog as we discuss reasons why you could fail an emissions test.

Worn Spark Plugs

If you have worn spark plugs, this could actually lead to an increase of toxic emissions. Some of these harmful gases include hydrocarbon and carbon monoxide. Also, be sure to check your spark plug wires and replace any that look worn. Simple replacements can set you up for success to pass your emissions test.

Leaky Gas Cap

Most car owners don’t need to worry about this, but a leaking gas cap can be the culprit of a failed test. You can check for leaks before your test quite easily. If there are signs of leakage, find a cap that seals to your tank properly.

Dirty Air Filter

Clogged air filters can reduce airflow to the engine, literally choking it, and as a result affect the emission control systems of the car. It can also cause high levels of hydrocarbons, so make sure to inspect and clean your air filter before the test.

Damaged Catalytic Converter  

A damaged catalytic convert cannot do its job properly, which is to convert toxic gases to ones that are not harmful. Not only is having a broken catalytic converter bad for the environment, but it’s also another way for you to fail the emissions test.


At H.W. Automotive Inc., we adhere to a high standard when it comes to emissions testing in Oklahoma City and surrounding areas. Our certified technicians will inspect your car and ensure all emissions standards are met. Call to schedule an automotive service with us today!