What Aurora emissions testing measures
Aurora emissions testing is a vehicle inspection method that measures what comes out of your tailpipe by analyzing the light wavelengths in your exhaust. Instead of drawing a sample of exhaust gas into a machine (the way traditional testing works), Aurora uses an infrared camera pointed at your tailpipe to read pollutants without touching the exhaust stream. The camera detects specific wavelengths of light that correspond to nitrogen oxides, carbon monoxide, carbon dioxide, and hydrocarbons — the main pollutants that cause smog and air quality problems.
The test takes about 30 seconds per vehicle and produces a pass or fail result on the spot. Because Aurora doesn't require a probe inserted into the tailpipe, it's faster than conventional testing and produces less wear on the equipment. Some states and counties have switched to Aurora testing as their primary emissions method, while others use it alongside traditional testing or as a retest option.
The key difference from your perspective as a vehicle owner is that Aurora testing is non-invasive and produces results when ready. You'll know whether your vehicle passed before you leave the testing station, rather than waiting for lab results or a mailed certificate.
Key Takeaways
- Aurora testing uses an infrared camera to read pollutants in your exhaust without inserting a probe into your tailpipe.
- The test measures nitrogen oxides, carbon monoxide, carbon dioxide, and hydrocarbons — the pollutants that contribute to smog.
- Results are available when ready after testing, so you know whether you passed before leaving the station.
- Aurora testing is faster than traditional testing methods and is now used in several states as the standard emissions inspection.
- A vehicle that fails Aurora testing can usually be retested at the same station after repairs, often the same day.
How the Aurora camera reads your exhaust
The Aurora system works by pointing an infrared camera at your tailpipe while your engine runs at a steady idle. The camera measures how much light is absorbed by different pollutants in the exhaust stream. Each pollutant absorbs light at a specific wavelength — carbon monoxide absorbs at one wavelength, nitrogen oxides at another, and so on. By measuring how much light is blocked at each wavelength, the camera calculates the concentration of each pollutant.
The testing station operator positions the camera at a standard distance from your tailpipe, usually about 12 to 16 inches away. The camera needs a clear view of the exhaust, so the operator may ask you to move your vehicle slightly or may clean the tailpipe opening if it's visibly dirty. The test itself takes about 30 seconds, during which your engine idles and the camera collects data.
Because the camera doesn't touch your vehicle, there's no risk of damage to your tailpipe or exhaust system. The test is also repeatable — if you fail and make repairs, you can be retested when ready without waiting for equipment to cool down or be recalibrated.
Pass and fail thresholds for Aurora testing
Whether your vehicle passes or fails depends on the emission standards set by your state or county. These standards vary by vehicle year, engine type, and sometimes by the county where you live. A 2005 sedan, for example, might have different thresholds than a 2015 truck, and standards in one county may be stricter than in a neighboring county.
The Aurora machine displays your results as a straightforward pass or fail, but behind that result are specific limits for each pollutant. If your nitrogen oxide level is above the limit for your vehicle type, you fail — even if your carbon monoxide is well below the limit. The testing station will print a receipt showing which pollutants, if any, exceeded the standard.
If you fail, the receipt will tell you which emissions are too high. This information helps a mechanic diagnose the problem — high nitrogen oxides often point to ignition timing or EGR system issues, while high carbon monoxide usually indicates a fuel mixture problem. Knowing which pollutant failed narrows down where a mechanic should look.
What to expect when you arrive for Aurora testing
When you pull up to an Aurora testing station, the operator will check your vehicle registration and ask you to drive into the testing bay. You'll be asked to keep your foot off the gas and let the engine idle while the camera does its work. The operator may ask you to rev your engine slightly or hold it at a specific RPM, depending on the testing protocol in your state.
The entire process from check-in to result usually takes 10 to 15 minutes, including paperwork. Once the camera finishes reading your exhaust, the machine prints your result when ready. If you pass, you'll receive a certificate or sticker (depending on your state) that shows your vehicle met emissions standards. If you fail, you'll get a detailed receipt showing which pollutants exceeded the limit and by how much.
Bring your vehicle registration and a valid ID. Some states require proof of insurance as well. If your vehicle has a check engine light on, some testing stations will refuse to test until the light is cleared, though this varies by location.
Failing Aurora testing and what to do next
If your vehicle fails Aurora testing, you have the option to make repairs and return for a retest. Most testing stations allow you to retest at no additional charge within a set timeframe — often 30 days — though you may have to pay a retest fee depending on your state. Some stations will retest you the same day if you make repairs quickly enough.
The receipt from your failed test is valuable information for a mechanic. It tells them exactly which emissions are too high, which narrows down the possible causes. A mechanic can use that information to diagnose the problem more quickly than if you straightforward told them "my vehicle failed emissions." Common repairs for failed emissions include replacing spark plugs, fixing a faulty oxygen sensor, repairing the catalytic converter, or addressing fuel system problems.
If repairs are expensive or your vehicle is very old, you may want to explore whether your state offers an emissions waiver program or a vehicle replacement program. These programs vary widely by state and county, so contact your local emissions testing authority to learn what options exist in your area.
Aurora testing versus traditional tailpipe testing
Traditional emissions testing uses a probe inserted into your tailpipe to draw a sample of exhaust gas into a machine that analyzes it chemically. Aurora testing, by contrast, reads the exhaust without touching it. Both methods measure the same pollutants and use the same state-set standards, so a vehicle that passes one method should pass the other.
The practical differences are speed and convenience. Aurora testing is faster — typically 30 seconds of actual measurement versus several minutes for traditional testing. Aurora equipment doesn't require calibration between tests, so testing stations can move vehicles through more quickly. There's also no wear on your tailpipe from a probe being inserted repeatedly.
Some states use Aurora as their primary testing method, while others use it as an alternative or a retest option. A few states still use only traditional testing. If you're unsure which method your state uses, contact your local emissions testing authority or check your state's environmental agency website.
States and regions currently using Aurora testing
Aurora testing is used in several states as either the primary emissions testing method or as an option alongside traditional testing. California, Colorado, and parts of Texas have implemented Aurora testing at some or all of their testing stations. However, the availability and use of Aurora testing changes over time as states update their testing programs.
The best way to find out whether Aurora testing is available in your area is to contact your state's environmental agency or visit your state's emissions testing website. You can also call a local testing station and ask whether they use Aurora, traditional, or both methods. If you're moving to a new state or county, check the local requirements before your registration expires — emissions testing rules vary significantly by location.
Frequently Asked Questions
Can I fail Aurora testing if my check engine light is on?
Yes. A check engine light indicates your vehicle's onboard diagnostic system has detected a problem, which often results in higher emissions. Many testing stations will refuse to test a vehicle with the check engine light on, or will test it and likely produce a fail result. Have the code read by a mechanic or at an auto parts store before testing.
What if my vehicle passes Aurora testing but fails traditional testing?
This is rare but can happen if the two methods measure slightly differently or if your vehicle's emissions are right at the borderline. If this occurs, contact your state's emissions testing authority — they can advise you on whether you can use the Aurora pass result or whether you need to retest using the traditional method.
How long does an Aurora test take?
The actual measurement takes about 30 seconds. The entire visit, including check-in, paperwork, and the test itself, usually takes 10 to 15 minutes. Results are printed when ready, so you know whether you passed before you leave the station.
Do I need to warm up my engine before Aurora testing?
Most testing stations will ask you to let your engine idle for a minute or two before testing to reach normal operating temperature. Ask the operator when you arrive — they'll tell you exactly what to do. Don't rev your engine or drive aggressively before testing, as this can affect your results.
What happens if I move to a state that uses a different testing method?
Your vehicle will need to pass that state's testing method to register there. If you're moving, research your new state's emissions testing requirements before you arrive. Some states accept out-of-state test results for a limited time, while others require you to retest when ready.