What Arizona requires for emissions testing
Arizona requires emissions testing for most vehicles registered in Maricopa and Pima counties—the Phoenix and Tucson areas. If you live in those counties, your vehicle must pass an emissions test every two years as part of your registration renewal. The test measures what comes out of your tailpipe: carbon monoxide, nitrogen oxides, and particulate matter. If your vehicle fails, you cannot renew your registration until you fix the problem and retest.
The rest of Arizona has no emissions testing requirement. If you live in a rural county or a smaller city outside the two major metro areas, you do not need to test. However, if you move from a non-testing county to Maricopa or Pima, you will need to test before your first registration renewal in that county.
Diesel vehicles, motorcycles, and vehicles model year 1975 and older are exempt from testing. Hybrid and electric vehicles are also exempt. If you own a vehicle that qualifies for an exemption, you still need to register it, but you skip the emissions test itself.
Key Takeaways
- Emissions testing is required every two years in Maricopa and Pima counties only; the rest of Arizona has no testing requirement.
- You must pass the test to renew your vehicle registration, and a failed test means you cannot legally register the vehicle until repairs are made and you retest.
- Testing stations are private businesses licensed by the Arizona Department of Environmental Quality, and you can choose any station in your county.
- The test itself costs between $20 and $30, and you can schedule an appointment or walk in at most stations.
- If your vehicle fails, you have 60 days to repair it and retest at no additional charge at the same station.
How to find a testing station and schedule
The Arizona Department of Environmental Quality maintains a searchable list of licensed testing stations on its website. You can search by county and city to find stations near you. Most stations are independent repair shops or quick-lube facilities that have been certified to perform emissions tests. You do not have to use your regular mechanic—any licensed station will do.
Many stations accept walk-ins, but calling ahead to schedule an appointment is faster and more reliable. When you call, tell them your vehicle's year, make, and model so they can confirm they can test it. Some stations have longer waits during peak times, especially near the end of the month when registrations are expiring. If you schedule early, you avoid the rush.
Bring your vehicle registration or proof of ownership and a valid ID. The test itself takes about 10 to 15 minutes. The station will plug a diagnostic machine into your vehicle's onboard computer port and measure the emissions from your tailpipe. You will get a printed receipt showing whether you passed or failed.
What happens if your vehicle fails the test
A failed test does not mean your vehicle is unsafe to drive—it means the emissions are above the legal limit for that model year. The test report will tell you which pollutant exceeded the limit: usually carbon monoxide, nitrogen oxides, or hydrocarbons. This information helps a mechanic know where to start looking for the problem.
Common causes of failure are a faulty oxygen sensor, a malfunctioning catalytic converter, a bad spark plug, or a leak in the fuel system. These are not catastrophic failures—they are fixable maintenance items. A mechanic can diagnose the specific problem using the test results and your vehicle's diagnostic codes.
You have 60 days from the date of the failed test to repair your vehicle and retest. The retest is free at the same station where you failed. You do not pay the testing fee again. Once you pass, you can complete your registration renewal. If you do not retest within 60 days, you will need to pay the full testing fee again at a new station.
Cost and timing for emissions testing
The test itself costs between $20 and $30 depending on the station. This is a one-time fee per test, not per attempt. If you fail and retest within 60 days, the retest is free. If you wait longer than 60 days, you pay the full fee again.
The entire process—from scheduling to getting your results—usually takes one visit of 15 to 30 minutes. You can often get results the same day. Some stations offer online scheduling, which lets you pick a time that works for you. Others operate on a first-come, first-served basis.
Plan to test before your registration expires. Your registration renewal notice will tell you the expiration date. Testing in the month before expiration gives you time to fix any problems and retest if needed. If you test too early—more than 60 days before expiration—your test results may expire before your registration does, and you may need to test again.
Preparing your vehicle for the test
You do not need to do anything special to prepare your vehicle for an emissions test. The test measures what your engine produces under normal operating conditions. However, a few basic maintenance items can help prevent failure: make sure your engine oil is at the correct level, your air filter is not clogged, and your fuel cap is tight and not cracked. A loose or missing fuel cap is a common reason for test failure because it allows fuel vapors to escape.
If your check engine light is on, your vehicle will likely fail the test. The light indicates a problem with the emissions system or engine. Have a mechanic read the diagnostic codes before you test. Fixing the underlying problem is cheaper than paying for multiple test attempts.
Drive your vehicle normally before testing. Some people think a long highway drive will "clean out" the engine, but this is not necessary. The test measures your vehicle's actual emissions, not a theoretical best-case scenario. What matters is that your vehicle is in the condition it will be in when you drive it every day.
What to do if you move or buy a used vehicle
If you move into Maricopa or Pima County from a non-testing area, you must test before your first registration renewal in the new county. The Arizona Motor Vehicle Division will not renew your registration without a passing test result. You have until your registration expires to complete the test.
If you buy a used vehicle in Arizona, the seller should provide you with a passing emissions test result if the vehicle is in a testing county. The test is valid for 60 days. If the test is older than 60 days or the vehicle is from out of state, you will need a new test before you can register it in Arizona. Plan for this cost and time when budgeting for a used vehicle purchase.
If you are buying a vehicle from out of state and moving it to Arizona, you will need to test it in Arizona before registration. The out-of-state test result does not count. Budget for the test fee and any repairs that might be needed to pass Arizona's standards.
Understanding your test results
A passing test result shows that your vehicle's emissions are within the legal limits for its model year. Older vehicles have higher allowable limits than newer ones because emission control technology has improved. Your test result will show the actual measurements and the legal limits for your specific vehicle.
If you fail, the report lists which pollutant exceeded the limit and by how much. Carbon monoxide and nitrogen oxides are the most common failures. The report may also show your vehicle's diagnostic trouble codes if any are stored in the computer. These codes help a mechanic understand what system is not working correctly.
Keep your passing test result until you renew your registration. You do not need to carry it with you, but you will need to show it to the Motor Vehicle Division when you renew. Some stations email results, and some print them on the spot. Ask the station how they will provide your results.
Frequently Asked Questions
Do I need an emissions test if I just moved to Arizona?
Only if you moved to Maricopa or Pima County. If you moved to any other county in Arizona, you do not need a test. If you moved to one of the two testing counties, you must test before your first registration renewal there, even if your vehicle passed a test in another state.
What if my vehicle is too old to test?
Vehicles model year 1975 and older do not need to test in Arizona. Diesel vehicles, motorcycles, and hybrids are also exempt. If your vehicle is exempt, you still register it normally—you just skip the emissions test step.
Can I test my vehicle before I buy it?
You can ask the seller to test it, but you are not required to. If you buy a used vehicle in a testing county, the seller should provide a passing test result if the vehicle is in their name. Once you own it, you are responsible for testing it before registration renewal.
What if I fail the test twice?
You can retest as many times as you need within the 60-day window, and each retest is free. If you fail twice, the problem may be more serious than a straightforward sensor or spark plug. Have a mechanic diagnose the vehicle instead of guessing at repairs. A proper diagnosis is cheaper than multiple failed tests.
Does my registration expire if I do not pass the emissions test?
Your registration will expire on its scheduled date, but you cannot renew it without a passing emissions test result. Once you pass, you can renew when ready. If your registration expires before you pass, your vehicle is not legally registered, and you should not drive it on public roads.