Back to all

Why did my vehicle fail its emissions test?

January 12, 2025

We all want to breathe clean air and keep our planet green.  One of the ways to do that is by requiring all vehicles with internal combustion engines to pass an emissions test.  That’s because these vehicles can be big polluters.  

Everyone wants their car to pass the test so they can continue their day-to-day driving routine.  But then comes that one day when they tell you your vehicle has failed.  Why does that happen?

One of the most common reasons is that your gas cap is leaking or loose (or maybe you don’t even have one on your vehicle!).  The gas cap is supposed to seal in vapors, but sometimes its seals or gaskets dry out or crack. Replace it, and you’re good to go.

Another common reason your vehicle failed the test is that your catalytic converter isn’t doing its job. It is supposed to convert toxic gases from your engine into ones that don’t pollute the air.  There are many reasons the catalytic converter may not be working.  It may be physically damaged, or the steady flow of exhaust gases has fouled the converter. 

You may have a bad oxygen sensor. It’s supposed to measure how much oxygen is in your exhaust.  This can cause the air-fuel mixture to be too rich, resulting in too many hydrocarbons in the exhaust. Your ignition system may also have problems, such as worn-out spark plugs.  Dirty fuel injectors can contribute to excess emissions.

Believe it or not, a dirty engine air filter may be the culprit. If it hasn’t been replaced for a while, your vehicle may be emitting too many hydrocarbons -  something that will cause your vehicle to fail the emissions test.

You can usually avoid a failed emissions test by maintaining your vehicle regularly.  The best way to do that is by bringing it to our trained technicians, so your vehicle gets the service it needs, scheduled and non-scheduled.  Plus, you’ll be doing your part to keep our air clean.

Tuffy Fort Wayne - Dupont Rd.
1910 W. Dupont Rd.
Fort Wayne, IN 46818
260.489.4800

More articles from Tuffy Fort Wayne (Dupont Rd.)

Positive and Negative (Battery Care)

June 15, 2025

You notice when your smartphone's battery starts to go weak on you. It runs out of juice faster than it did when it was new. Bet you pay attention to that pretty closely. Unfortunately, many of us don't pay the same attention to the battery in our vehicles. If your battery got you through the c... More

Clean Machine (Fuel and Air Induction Cleaning)

June 9, 2025

As your vehicle ages, its performance isnt quite what it used to be, but many of us never notice the change because its gradual. So here are a few questions to ask yourself. Does your vehicle feel like it doesnt have the pep that it used to? Have you noticed your fuel economy isnt quite as good... More

Strutting Your Stuff (Shocks and Struts)

June 2, 2025

Ever wonder how your vehicle is able to move over bumps, potholes and other irregularities in the road and you hardly feel a vibration in the cabin? Its your shocks and struts doing the hard work along with the rest of your suspension and tires. They keep the ride smooth and are important for yo... More