What Arizona emissions testing requires

Arizona requires emissions testing for most vehicles registered in Maricopa and Pima counties — the Phoenix and Tucson areas. If you live in those counties, you must pass an emissions test every two years as part of your vehicle registration renewal. The test checks whether your vehicle's exhaust meets state air quality standards.

The test itself takes about 10 minutes. A technician connects a probe to your vehicle's tailpipe and measures the levels of nitrogen oxides, carbon monoxide, and other pollutants in your exhaust. Your vehicle passes or fails based on whether those levels fall within Arizona's limits for your vehicle's year and type.

If you live outside Maricopa and Pima counties, you do not need an emissions test — Arizona does not require it statewide. You can renew your registration without one. However, if you move to a county that does require testing, you will need to get tested before your next renewal.

Key Takeaways

  • Emissions testing is required every two years in Maricopa and Pima counties only; other Arizona counties do not require it.
  • You can get tested at any Arizona Department of Environmental Quality (ADEQ) certified testing station, including many repair shops and service stations.
  • The test costs between $20 and $30 depending on your vehicle type and the testing station.
  • You must pass the test before you can renew your vehicle registration in a county that requires it.
  • If your vehicle fails, you have 60 days to repair it and retest at no additional charge at the same station.

Finding a testing station in your area

The Arizona Department of Environmental Quality maintains a searchable list of certified testing stations on its website. You can search by zip code or city to find stations near you. Most are independent repair shops, dealerships, or service stations that have been certified to perform the test.

Call ahead before you go. Testing stations have different hours, and some get busy during peak times — typically the weeks before registration renewal important date. A quick call confirms they are open and tells you how long the wait is.

You do not need an appointment at most stations, but some larger facilities do take them. If you know your registration renewal date is coming up, scheduling ahead can save you time.

What to bring and what happens during the test

Bring your vehicle registration or proof of ownership and a valid photo ID. The technician will ask for your vehicle identification number (VIN), which is on your registration and also on the dashboard at the base of the windshield on the driver's side.

The technician will connect a probe to your tailpipe and run the test while your vehicle is idling. The whole process takes about 10 minutes. You will see the results on a printout before you leave. If you pass, the station sends the results electronically to the Arizona Motor Vehicle Division, and you can renew your registration.

If you fail, the printout will show which pollutants exceeded the limit. You have 60 days to have your vehicle repaired and retested at the same station at no charge. The retest is free because the station is required to offer it under Arizona law.

Common reasons vehicles fail the test

The most common reason for failure is a faulty oxygen sensor or a problem with the catalytic converter. Both of these are emissions control parts that wear out over time. A check engine light on your dashboard often signals one of these problems.

Other common failures come from a loose or missing gas cap, which lets fuel vapors escape, or a malfunctioning fuel injector. Older vehicles and those with high mileage fail more often than newer ones, but any vehicle can fail if a part breaks.

If your vehicle fails, a repair shop can run a diagnostic test to pinpoint the problem. This usually costs $50 to $100 and tells you exactly what needs to be fixed. Many shops will waive the diagnostic fee if you have the repair done there.

What to do if your vehicle fails

You have 60 days from the test date to repair your vehicle and return to the same testing station for a retest. The retest is free. You do not need to pay the testing fee again.

If you cannot afford the repair right away, you can request a 30-day extension from the testing station. You will need to show proof that you have taken your vehicle to a repair shop — usually a written estimate or invoice. Extensions are not automatic, but stations grant them in most cases.

If you do not retest within 60 days, or 90 days if you got an extension, your registration will not renew. You will need to pass the test before you can register your vehicle again.

Vehicles exempt from testing

New vehicles are exempt for the first four model years. A vehicle registered for the first time in 2024 does not need to be tested until 2028. After that, it follows the regular two-year testing cycle.

Vehicles that are more than 40 years old are also exempt. This applies to classic and antique vehicles, though you may need to register them under a special antique vehicle classification.

Diesel vehicles have different testing standards than gasoline vehicles. If you own a diesel truck or car, the testing station will use a different test procedure designed for diesel engines.

Renewing your registration after you pass

Once you pass the test, the testing station sends your results to the Arizona Motor Vehicle Division electronically. You can then renew your registration online through the Arizona Department of Transportation website, by mail, or in person at a Motor Vehicle Division office.

You do not need to bring the test results with you — the Motor Vehicle Division already has them. Your registration renewal will show that the emissions test requirement has been met.

Your registration is valid for two years from the renewal date. You will need to test again two years later if you still live in Maricopa or Pima county.

Frequently Asked Questions

What if I just moved to Arizona from out of state?

If you move to Maricopa or Pima county, you must get an emissions test before you can renew your registration. When you register your vehicle in Arizona, the Motor Vehicle Division will tell you whether testing is required based on your address. You have until your registration renewal date to get tested.

Can I test my vehicle before my registration expires?

Yes. You can test up to 60 days before your registration expires. This is useful if you want to get the test done early and avoid the rush before the renewal important date. The test results are valid for two years from the test date.

What if I move out of a county that requires testing?

If you move from Maricopa or Pima county to a county that does not require emissions testing, you no longer need to test. You can renew your registration without a test. However, if you move back to a testing county later, you will need to test again before your next renewal.

How much does the test cost?

The test costs between $20 and $30 depending on your vehicle type and the testing station. Diesel vehicles and motorcycles may have different fees. Call the station ahead of time to confirm the exact price.

What if my vehicle has a check engine light on?

Most testing stations will not test a vehicle with an active check engine light. You will need to have the problem diagnosed and repaired first, then clear the light before testing. A repair shop can do this diagnostic for $50 to $100.