What Should I Do If My Car Fails an Emissions Test?

What Should I Do If My Car Fails an Emissions Test? | Autobahn Auto Repair

Getting your car ready for an emissions test is something most drivers don’t give much thought to—until their vehicle fails. It can be frustrating and stressful, especially if you're unsure what went wrong or how to fix it. But don’t worry! There’s a straightforward path to getting your car back in compliance and back on the road.

   Emissions Testing

Emissions tests measure the amount of harmful pollutants your vehicle releases into the air. States and cities require these tests to ensure cars meet environmental standards, reduce air pollution, and protect public health.

When your car fails an emissions test, it’s a sign that something isn’t functioning as it should—whether it’s a worn-out part, a temporary issue, or even a problem with the way your car burns fuel. Knowing what to do next can save you time, money, and a lot of headaches.

   Step 1: Don’t Panic—Check Your Test Results

First things first: take a close look at your test results. These reports usually include details about which pollutants your car failed to control and might even hint at the underlying problem. Did your car exceed limits for carbon monoxide, hydrocarbons, or nitrogen oxides? Or was there an issue with the onboard diagnostic system (OBD)?

Find out what caused the failure. Some issues, like a loose gas cap, are simple to fix. Others, like a failing catalytic converter, require professional attention and expertise.

   Step 2: Investigate the Cause

Once you have your test results, you’ll want to figure out what’s causing the issue. Common reasons for failing an emissions test include:

  • Faulty Oxygen Sensors: These sensors monitor the air-fuel mixture in your engine. If they’re not working correctly, your car might burn too much fuel, leading to higher emissions.
  • Catalytic Converter Problems: This component reduces harmful emissions by converting them into less harmful gases. If it’s damaged, emissions will spike.
  • Check Engine Light On: If your check engine light is illuminated, your car will likely fail an emissions test automatically, regardless of the actual emissions levels.

If you’re handy with cars, you might troubleshoot some of these issues yourself. However, for most people, the best option is to seek professional help.

   Step 3: Get Professional Diagnostics and Repairs

The quickest way to address a failed emissions test is to visit a trusted repair shop. Our qualified technicians can perform diagnostics to pinpoint the exact cause of the failure and recommend the appropriate fix. Here’s what might happen during this process:

  • Your vehicle’s computer system will be scanned for error codes, which can provide valuable clues about what went wrong.
  • Components like the oxygen sensor, catalytic converter, and fuel system will be inspected for wear or damage.
  • Any faulty parts will be repaired or replaced, ensuring your vehicle runs more efficiently and emits fewer pollutants.

   Step 4: Perform a Retest

After addressing the issue, it’s time to schedule a retest. Most emissions testing facilities allow a retest for free or at a reduced cost within a specific timeframe. Be sure to drive your car for at least a few days before retesting, as this helps reset the onboard diagnostic system and ensures the repairs are working effectively.

If your car passes, you’re good to go! If not, it might indicate a deeper issue that wasn’t fully resolved. In this case, return to the repair shop for further diagnostics.

   Preventing Future Failures

Failing an emissions test is inconvenient, but it’s also a reminder to stay on top of your car’s maintenance. Regular tune-ups, oil changes, and inspections can help identify small issues before they become major problems. Keeping your car in good condition also reduces emissions, improves fuel efficiency, and prolongs the life of your vehicle.

If you live in a state with annual or biannual emissions testing, consider performing a pre-test inspection a few weeks before your scheduled test. This gives you time to address any issues without the pressure of an approaching deadline.


Did your car fail its emissions test? Bring it to Autobahn Auto Repair for expert diagnostics and repairs. We’ll get your car back on the road and running clean in no time!