What Air Care Colorado Tests and Why It Matters

Air Care Colorado is the state's vehicle emissions testing program, run by the Colorado Department of Public Health and Environment. When you take your vehicle to an Air Care test center, technicians measure what comes out of your tailpipe—specifically nitrogen oxides, particulate matter, and hydrocarbons—to confirm your car meets Colorado's air quality standards. The test takes about 10 minutes and costs between $20 and $30, depending on the test center.

Colorado requires emissions testing in the Denver metro area and a few other regions where air quality is monitored closely. If you live in one of these areas and your vehicle is registered there, you must pass an emissions test every two years (or every year if your car is model year 2000 or older). Vehicles that fail the test cannot be registered, which means you cannot legally drive them on public roads until repairs are made and you retest.

Key Takeaways

  • Air Care Colorado tests what comes out of your tailpipe to measure whether your vehicle meets state air quality standards, and you must pass to renew your registration in regulated areas.
  • The test itself takes about 10 minutes and costs $20 to $30; you can find test centers and schedule appointments through the official Air Care Colorado website.
  • Vehicles fail most often because of a faulty oxygen sensor, catalytic converter problems, or a check engine light that is on—all of which affect emissions but are fixable.
  • If your vehicle fails, you have 60 days to make repairs and retest at no additional charge; after 60 days, you pay the full test fee again.
  • Newer vehicles (model year 2000 and later) test every two years; older vehicles test annually, and some vehicles are exempt entirely based on age or type.

Finding an Air Care Test Center and Scheduling

You can locate test centers and book an appointment through the official Air Care Colorado website at aircareco.com. The site shows all active test centers in your area, their hours, and real-time availability. You can schedule online or call the center directly. Most centers operate during business hours and some on weekends, so you have flexibility in when you go.

Bring your vehicle registration, proof of insurance, and a valid ID. Your vehicle's odometer reading will be recorded during the test. If your check engine light is on, the test center will scan your vehicle's computer to read any fault codes before running the emissions test—this is part of the standard procedure and does not cost extra.

How the Emissions Test Actually Works

When you arrive at the test center, a technician will guide your vehicle onto a dynamometer—a machine with rollers that your car drives onto. The dynamometer simulates driving conditions while measuring the exhaust gases your vehicle produces. You will sit in the car while this happens; the test runs through two cycles that mimic city driving and highway driving.

The machine records the levels of nitrogen oxides, particulate matter, and hydrocarbons in your exhaust. Your vehicle passes if these levels fall below the limits set by Colorado law for your vehicle's model year and engine type. The results are printed when ready, and you will know whether you passed or failed before you leave.

The test does not measure carbon dioxide or fuel economy. It focuses on pollutants that affect air quality and human health. If your vehicle has a diesel engine, a hybrid system, or is electric, different standards explore—the test center will know which test your vehicle needs.

Why Vehicles Fail and What to Do Next

The most common reasons for failure are a faulty oxygen sensor, a damaged catalytic converter, a misfire in one or more cylinders, or a check engine light that is on. These problems all affect how your engine burns fuel and what comes out the tailpipe. A clogged air filter, worn spark plugs, or a fuel system problem can also cause failure.

If your vehicle fails, you have 60 days from the test date to have repairs made and retest at no charge. After 60 days, you must pay the full test fee again. When you retest, bring your repair receipt or documentation showing what was fixed—test centers do not require this, but it helps you track what was done.

If repairs are expensive and your vehicle is older, you may want to get a second opinion from a trusted mechanic before spending money. Some repairs—like replacing a catalytic converter—are costly, but they also improve fuel economy and engine performance, so the benefit extends beyond just passing the test.

Vehicles Exempt from Air Care Testing

Not every vehicle in Colorado needs to test through Air Care. Vehicles model year 2000 and older that are registered outside the Denver metro area and other regulated regions do not test. Vehicles model year 1975 and older are exempt statewide. Electric vehicles and some hybrid vehicles have different requirements or are exempt entirely.

Vehicles registered in counties outside the Air Care testing areas—such as rural areas of Colorado—do not need to test at all. You can check whether your vehicle is in a regulated area by entering your ZIP code on the Air Care Colorado website. If you move to a different county or state, your testing requirements may change.

What Happens If Your Vehicle Fails and You Cannot Afford Repairs

If your vehicle fails and repairs are beyond your budget, you have limited options within the Air Care program itself. However, some repair shops offer payment plans or financing for emissions-related work. You can also reach out to local nonprofits or community action agencies in your area—some offer information with vehicle repairs for low-income households, though availability varies by county.

If you cannot repair your vehicle within 60 days, your registration will not renew. This means you cannot legally drive the vehicle on public roads. At that point, your options are to delay registration until repairs are complete, sell the vehicle, or explore whether a different vehicle would be more practical for your situation.

Preparing Your Vehicle Before the Test

Before you schedule a test, make sure your vehicle has been driven for at least 20 minutes so the engine is warm. A cold engine can produce higher emissions readings and cause an unnecessary failure. Check that your gas cap is tight—a loose or missing cap can trigger a check engine light and cause a test failure.

If your check engine light is on, have the code scanned before you test. Many auto parts stores will scan the code for free, and knowing what the problem is helps you decide whether to repair it before testing or wait to see if the vehicle fails. Some check engine codes do not affect emissions and will not cause a test failure, but others will.

Frequently Asked Questions

Can I test my vehicle if the check engine light is on?

Yes, you can test with the light on. The test center will scan your vehicle's computer to read the fault code as part of the standard procedure. However, many check engine codes indicate problems that will cause an emissions test failure, so you may want to have the issue diagnosed first.

What if I fail the test and the repair shop says the problem is not emissions-related?

Air Care tests only emissions-related components. If a repair shop tells you the failure is caused by something unrelated to emissions, ask them to explain which specific emissions component is faulty. You can also request a second opinion from another shop or contact Air Care Colorado directly if you believe the test result is incorrect.

Do I have to test at an official Air Care center, or can a mechanic do it?

You must test at an official Air Care Colorado test center. Only these centers produce results that satisfy Colorado's registration requirement. A mechanic can diagnose emissions problems and repair them, but the official test is the only one that counts.

How long does it take to get my test results?

You receive your results when ready when the test is complete, usually within 10 to 15 minutes from when you arrive. The test center prints a pass or fail notice on the spot, and the results are also sent to the Colorado Division of Motor Vehicles electronically.

What if I move out of the Air Care testing area?

If you move to a county outside the regulated testing area, you will no longer need to test through Air Care. When you update your vehicle registration with your new address, the requirement will drop automatically. Check the Air Care Colorado website with your new ZIP code to confirm whether testing is required in your new location.