What Arizona requires for emissions testing

Arizona requires emissions testing for most vehicles registered in Maricopa and Pima counties — the state's two most populated areas. If you live outside those counties, you do not need to test. If you live in one of them, you must pass an emissions test every two years as part of your vehicle registration renewal.

The test itself is straightforward: a technician plugs a diagnostic scanner into your vehicle's onboard computer port and reads the emissions data. The vehicle does not need to run on a dynamometer (a treadmill-like machine). The entire process takes about 10 to 15 minutes and costs between $20 and $30, depending on the testing station.

Your vehicle must pass the test to renew your registration. If it fails, you have 60 days to fix the problem and retest at no additional charge. After 60 days, you pay the testing fee again.

Key Takeaways

  • Arizona requires emissions testing only in Maricopa and Pima counties; all other Arizona counties do not require it.
  • The test reads your vehicle's onboard computer data and takes about 10 to 15 minutes at a licensed testing station.
  • You must pass the test to renew your vehicle registration every two years.
  • If you fail, you have 60 days to repair the problem and retest for free; after 60 days, you pay the testing fee again.
  • Vehicles older than 1975 and some other exemptions do not require testing — check the Arizona Department of Environmental Quality website to confirm your vehicle's status.

Which Arizona counties require testing

Only Maricopa County (which includes Phoenix) and Pima County (which includes Tucson) have emissions testing requirements. Every other county in Arizona — including Coconino, Yavapai, Mohave, and all others — does not require it.

If you are unsure whether your county requires testing, check your vehicle registration renewal notice. It will state whether an emissions test is required. You can also contact your county assessor's office or the Arizona Department of Environmental Quality to confirm.

How to find a testing station and schedule an appointment

Arizona maintains a list of licensed emissions testing stations on the Arizona Department of Environmental Quality website. You can search by city or ZIP code to find stations near you. Most stations are independent repair shops, not dealerships.

Many stations accept walk-ins, but calling ahead to confirm hours and current wait times is a good idea. Some stations book appointments online or by phone. Bring your vehicle keys and proof of ownership (your registration or title) when you arrive.

Testing stations are open year-round, but they are busiest in the weeks before registration renewal important date. If your registration expires in a particular month, you can test anytime in the two months before that important date.

What happens if your vehicle fails the test

If your vehicle fails, the testing station will give you a printed report showing which emissions standards your vehicle did not meet. Common failure reasons include a faulty oxygen sensor, a malfunctioning catalytic converter, or a check engine light that is on.

You then have 60 days to repair the problem and return to any testing station for a retest. The retest is free during that 60-day window. Once you pass, the testing station sends the results to the Arizona Department of Motor Vehicles, and you can renew your registration.

If you do not retest within 60 days, your registration cannot be renewed until you test again and pay the testing fee. Some repair shops can diagnose the problem for $50 to $100 if you are unsure what needs fixing.

Vehicles that do not require emissions testing in Arizona

Certain vehicles are exempt from Arizona emissions testing even if you live in Maricopa or Pima County. Vehicles manufactured before 1975 do not require testing. Diesel vehicles registered before 2010 are also exempt. Some newer diesel vehicles may be exempt depending on their model year and registration date.

Motorcycles, mopeds, and vehicles with a gross vehicle weight rating over 14,000 pounds do not require testing. If you are unsure whether your vehicle is exempt, the Arizona Department of Environmental Quality website has a full exemption list, or you can ask the testing station when you call.

Understanding your emissions test results

An emissions test measures two main things: whether your vehicle's onboard diagnostic system is working properly, and whether your vehicle is emitting pollutants within legal limits. The test does not measure how much fuel you use or how your vehicle performs on the road.

If you pass, the testing station prints a pass certificate and sends the results electronically to the Arizona Department of Motor Vehicles. You can then renew your registration online, by mail, or in person at your county assessor's office. You do not need to bring the pass certificate with you — the DMV already has the results.

If you fail, the report will show which specific emissions standards were not met. This information helps a mechanic diagnose what needs repair. Some common fixes are inexpensive (replacing an oxygen sensor costs $100 to $300), while others are more costly (catalytic converter replacement can run $500 to $1,500 depending on the vehicle).

Frequently Asked Questions

Do I need an emissions test if I just moved to Arizona?

If you move to Maricopa or Pima County and register your vehicle in Arizona, you will need to pass an emissions test before you can renew your registration. If you move to a county that does not require testing, you do not need one. Check your registration renewal notice or contact your county assessor to confirm the requirement for your location.

Can I test my vehicle before my registration expires?

Yes. You can test anytime in the two months before your registration renewal important date. Testing early gives you time to repair any problems and retest if needed. The test results are valid for your entire two-year registration period.

What if my check engine light is on?

A check engine light usually means your vehicle will fail the emissions test. You should have a mechanic diagnose the problem before testing. Many repair shops can read the code for free or for a small fee. Once the problem is fixed, the light should turn off, and you can retest.

Can I renew my registration if I have not tested yet?

No. In Maricopa and Pima counties, you cannot renew your registration without a passing emissions test result. If your registration expires before you test, you cannot legally drive the vehicle. Schedule your test at least a few weeks before your renewal important date to allow time for repairs if needed.

How much does an emissions test cost in Arizona?

The test itself costs between $20 and $30 at any licensed testing station. This is the only fee you pay for testing. If you fail and need to repair your vehicle, repair costs depend on what is wrong — that is separate from the testing fee.