6 Reasons Why Your Vehicle Failed its Emissions Test

We care about the air we breathe which is why all vehicles in Marietta, GA, must pass a yearly emissions test. There are several reasons why your vehicle will fail the emissions test, but don’t panic if it does. TRUE Automotive cannot only determine why your car, truck, or SUV failed the test but also fix the problem so it passes the retest. Here are six reasons why a vehicle fails an emissions test.

Dirty Oil

If you haven’t had your oil changed regularly and are overdue for a lube, oil, and filter, your vehicle might fail its annual emissions test. Dirty oil has a higher concentration of hydrocarbons and these hydrocarbons will return a failed test result. Clean motor oil has fewer hydrocarbons.

Rich Air/Fuel Mixture

Your vehicle needs both air and gasoline to start and run. The ratio of air to fuel is specific, and if this mixture is too rich in air or fuel, your vehicle might fail its emissions test. Usually, a problem with the fuel injectors, oxygen sensor, or mass airflow filter causes the air/fuel mixture to be off.

Old Spark Plugs

Old or faulty spark plugs may also return an emissions test failure. The spark plugs are part of your vehicle’s combustion system. If the spark plugs are worn or aren’t firing in the correct order, your engine’s combustion is affected and your vehicle could fail an emissions test because of this.

Unsealed Gas Cap

Your gas cap is designed to seal off the tank and create a vacuum. If the cap is too loose or cannot form an airtight seal anymore, your vehicle will fail a yearly emissions test. In fact, your check engine light will come on, too, and alert you of trouble. The gas tank needs to be sealed for your car to run properly.

Dirty Air Filter

As with dirty motor oil, a dirty air filter will create an issue with hydrocarbons and return a failed emissions test. It’s best to change your air filter every 12,000 to 15,000 miles to prevent hydrocarbon buildup in your engine. This can be a DIY job or we’d be happy to replace it for you.

Activated Check Engine Light

Finally, if your check engine light is on and you’ve been ignoring it because your vehicle runs just fine, your car, truck, or SUV will not pass the emissions test. In many cases, the check engine light comes on because there is an emissions issue, such as a problem with your catalytic converter or oxygen sensor.

Bring your European automobile into TRUE Automotive if it failed its emissions test. Call us at 770-214-4688 to schedule an appointment. We’ll find the problem and fix it.