As part of its effort to reduce air pollution, the federal Clean Air Act requires vehicle owners to have their emissions checked. Due to the EPA’s stringent emissions standards, many car owners have to regularly check their vehicles to ensure they’re not contributing to air pollution.

Are Vehicle Owners Required to Get Emissions Testing?

As of today, more than 30 states have laws that require the testing of emissions. You can check the exact requirements in your state by visiting the EPA’s website.

How Is the Testing Procedure Completed?

The purpose of an emissions test is to determine the pollutants that your car produces and how it can reduce its emissions. Some of these include carbon dioxide, hydrocarbons, and oxides of nitrogen. Depending on the type of test conducted, it can take about 15 to 30 minutes to complete. 

When taking your car in for an emissions test, mechanics will perform the following: 

  • Two-Speed Idle (TSI) Testing- This test is often for older cars. The test will track exhaust emissions when the vehicle’s engine is idling at low and high speeds.
  • On-Board Diagnostic (OBD) Inspections- The most common type of test performed for older cars is the Onboard Diagnostic test. This procedure checks the data collected by the car’s internal emissions system. This test is done on cars from the model year 1996 and older. It will also ensure the “check engine” light is properly working.
  • Acceleration Simulation Mode (ASM) Testing- Since many cars made before 1995 don’t have an OBD system, many of them require a different type of test to measure their emissions. An ASM test uses a dynamometer and a tailpipe sensor to simulate driving conditions to measure emissions.

What Happens After Passing the Emissions Test?

After receiving the results, you should immediately get in touch with your local motor vehicle agency to confirm the status of your test. You can also check the status of your vehicle by calling the agency’s office.

What Will Happen if My Vehicle Doesn’t Pass the Testing?

If you go for emissions testing and your vehicle fails, you will not be allowed to drive your vehicle until you get the necessary repairs completed and pass a second test.

Your test results should also inform you about the various issues that caused your car to fail. Having these details will allow you to identify the repairs that are needed to keep your vehicle running smoothly.

Some common reasons your vehicle may have failed its emissions test include:

  • Sample Dilution Failure- This will happen if your vehicle could not produce a valid exhaust sample. This can be due to poor engine adjustments or a leak in your car’s exhaust system.
  • Excessive CO or HC Levels- There are maximum limit standards for the amount of CO and HC your vehicle is allowed to emit. If these limits pass the established standards, your car will fail the test.
  • OBD Failure- This failure means your vehicle’s malfunction indicator light (MIL) on the dashboard is malfunctioning or the OBD controls are not working properly.
  • No Emissions Control Equipment- There is equipment in your vehicle that is necessary to run the emissions testing. If it has been disconnected or is absent, your car will fail the test.
  • Gas Cap- A loose gas cap can be another common reason your vehicle will fail the testing. If it doesn’t create a tight seal, your gas tank could leak vapors. This is often a problem seen in older vehicles that have worn gas caps.

Aside from regular maintenance, performing a diagnostic test is also helpful for avoiding a failed test. Before the test, have your vehicle checked by a mechanic. Doing so helps minimize the chances of your car failing.

Having the necessary equipment and procedures in place can help keep your vehicle on the road and protected from possible damages. Visit Pinecrest Shell & Auto Repair for an evaluation before your emissions test. They will help you get and keep your car legally roadworthy.

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