Common Reasons Your Vehicle Might Fail an Emissions Test

Common Reasons Your Vehicle Might Fail an Emissions Test

Many state governments require individuals to perform an emissions test on their vehicle before they can register it for the year. Emissions tests ensure the vehicle you drive is safe for the environment, and a failed test could result in costly repairs and a ticket. To get ahead of this issue, here are some common reasons your vehicle might fail an emissions test.

Check Engine Light Is On

The easiest reason why your vehicle might fail an emissions test has to do with the check engine light. More often than not, if the check engine light is on, whether it’s defective or if it’s trying to tell you there’s a real issue, you will fail an emissions test. A defective engine light is usually an easy fix.

Loose or Leaking Gas Cap

Your vehicle may also fail the emissions test if its gas cap seal has worn down. A loose or leaking gas cap can lead to excessive fumes coming from the fuel tank. The good news is this can be an easy fix since all you must do is get a new Jeep Wrangler gas cap cover, available at AM Off-Road.

Worn Spark Plugs

Another common reason your vehicle might fail an emissions test has to do with the spark plugs. A vehicle’s spark plugs are vital to the engine, and if they exceed their mileage interval, you could fail your emissions test.

Dirty Air Filter

A dirty air filter could also be the cause of a failed emissions test. A dirty air filter can produce high levels of carbon monoxide, which will result in a failed emissions test. Make sure you replace your vehicle's air filter at least once a year to prevent this issue.

Damaged EVAP System

The job of a vehicle’s EVAP system is to keep gasoline vapors inside the vehicle’s fuel tank. If there is any damage to the EVAP system, you could fail an emissions test, as these gasses can enter the atmosphere and harm the environment.

Catalytic Converter Damage

The catalytic converter is an integral part of your engine because it converts toxic gases into nontoxic emissions. A good way to tell if you have catalytic converter damage is if you see dark smoke coming out of your exhaust or detect an odor that smells like rotten eggs. Exhaust fumes could also point to a bad O2 sensor, which can also be the reason behind a failed emissions test.

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