What ADOT's emissions program requires

Arizona's Department of Transportation (ADOT) runs the state's vehicle emissions testing program, which requires certain vehicles to pass an emissions test every two years. The test measures what comes out of your tailpipe — carbon monoxide, nitrogen oxides, and particulate matter — to confirm your vehicle meets federal air quality standards.

Not every vehicle needs testing. Gasoline-powered cars, light trucks, and motorcycles registered in Maricopa or Pima counties must test. Diesel vehicles, vehicles over 14,000 pounds, and vehicles registered outside those two counties are exempt. Your registration paperwork will tell you whether your vehicle is subject to testing.

You can take your vehicle to any ADOT-certified emissions testing station. The test itself takes about 10 minutes and costs between $20 and $30, depending on the station. You do not need an appointment at most locations, though some stations accept them.

Key Takeaways

  • Gasoline vehicles in Maricopa and Pima counties must pass an emissions test every two years or face registration suspension.
  • The test costs $20 to $30 and takes about 10 minutes at any ADOT-certified testing station.
  • You can find certified stations through ADOT's online locator or by calling 602-255-0072.
  • If your vehicle fails, you have 60 days to repair it and retest at no additional cost.
  • Vehicles that fail twice in a row may be subject to stricter testing or removal from the road.

Finding a testing station and scheduling

ADOT maintains a list of certified emissions testing stations on its website at azdot.gov. You can search by county or city to find stations near you. Most stations are open during standard business hours, and many stay open into the evening or operate on weekends.

Walk-ins are accepted at nearly all stations, so you do not need to plan ahead. If you prefer to schedule a time, many stations offer online booking or accept phone reservations. Call the station directly to ask whether they take appointments.

Bring your vehicle registration and a valid photo ID. Some stations may ask for your vehicle identification number (VIN) before you arrive, which you can find on your registration or inside the driver's side door jamb.

What happens if your vehicle fails the test

If your vehicle does not pass, the testing station will give you a detailed report showing which emissions exceeded the limit. You then have 60 days to repair the vehicle and return for a retest. The retest is free — you pay only if you fail a second time.

Common repairs that fix emissions failures include replacing a faulty oxygen sensor, fixing a loose gas cap, or addressing problems with the catalytic converter. A mechanic can read the test report and tell you what needs fixing. You do not have to use a specific shop; any licensed mechanic can do the work.

If you fail the test twice in a row, ADOT may place your vehicle on a failure list, which can result in more frequent testing requirements or, in some cases, removal from registration. This is rare and usually happens only after multiple failures over several years.

Renewing your registration with a passing test

Once your vehicle passes, the testing station sends the result electronically to ADOT. You do not need to bring the test results to the Motor Vehicle Division — ADOT already has them. When you renew your registration online, by mail, or in person, the system will show that your vehicle passed.

Your registration will be suspended if the emissions test is overdue. If this happens, you cannot legally drive the vehicle until you pass the test and renew your registration. You can renew registration online at azdot.gov, by mail, or at any Motor Vehicle Division office.

Vehicles that may be exempt or on a different schedule

Diesel vehicles, vehicles manufactured before 1975, and vehicles over 14,000 pounds are permanently exempt from emissions testing. Vehicles registered outside Maricopa and Pima counties are also exempt, even if they are gasoline-powered.

New vehicles are exempt for the first four model years. After that, they enter the regular two-year testing cycle. If you move to Arizona with a vehicle registered in another state, check with the Motor Vehicle Division about when your first test is due — timing depends on when you register it in Arizona.

Some vehicles may may have access to for a temporary waiver if they are undergoing repairs. Contact ADOT directly to ask whether your situation qualifies.

Contacting ADOT about emissions questions

ADOT's emissions program line is 602-255-0072. You can also visit an ADOT office in person or check the website at azdot.gov for program details, station locations, and answers to common questions.

If you believe your vehicle was tested incorrectly or your results are wrong, you can request a retest at a different station. Bring your original test results and explain your concern to the new station.

Frequently Asked Questions

Do I have to test my vehicle if I just moved to Arizona?

If you registered your vehicle in Arizona and live in Maricopa or Pima county, yes — your first test is due two years after registration. If you moved from out of state, the two-year clock starts when you register it in Arizona, not when you bought it.

What if I fail the test and cannot afford repairs?

Arizona does not offer state-funded repair information for emissions failures. However, some nonprofits and community action agencies in Maricopa and Pima counties offer low-cost repair programs. Contact your local community action agency or call 211 to ask about repair information in your area.

Can I drive my vehicle if my registration is suspended for a failed emissions test?

No. Driving with a suspended registration is illegal and can result in a traffic citation. You must pass the emissions test and renew your registration before driving the vehicle on public roads.

How long does it take to get my test results?

Results are available when ready after testing. The station prints a receipt showing whether you passed or failed. ADOT receives the results electronically the same day.

What if my vehicle has a check engine light on?

You can still test your vehicle, but it will likely fail. The check engine light indicates a problem that usually causes emissions to exceed limits. Have a mechanic diagnose the problem before testing.