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 in those counties and your vehicle is model year 1975 or newer, you will need to pass an emissions test every two years as part of your vehicle registration renewal.

Vehicles registered outside Maricopa and Pima counties do not need emissions testing in Arizona, regardless of age. If you move from a non-testing county to a testing county, you will need to get tested before your registration renewal is due.

Some vehicles are exempt even in testing counties: electric vehicles, vehicles with a model year more than 40 years old, and vehicles that have been registered in Arizona for less than 60 days. Diesel vehicles have different requirements — they are tested only in certain years and must meet separate standards.

Key Takeaways

  • Emissions testing is required every two years in Maricopa and Pima counties only, and applies to vehicles model year 1975 and newer.
  • You must pass the test before you renew your vehicle registration, and the test costs between $20 and $30 depending on your vehicle type.
  • You can get tested at any Arizona Department of Transportation (ADOT) emissions testing facility or at a private testing station that holds an ADOT contract.
  • If your vehicle fails, you have 30 days to repair it and retest at no additional charge at the same facility.
  • Hybrid vehicles and vehicles with fewer than 6,000 miles on the odometer may be exempt from testing in their first two-year cycle.

Where to get your vehicle tested

ADOT operates emissions testing stations in both Maricopa and Pima counties. You can find the location nearest you on the ADOT website by entering your ZIP code. Testing stations are open during standard business hours, and you do not need an appointment at most locations — you can walk in during operating hours.

Private testing stations also perform emissions tests under ADOT contract. These stations are often located at repair shops, tire retailers, and service centers. A private station must display its ADOT authorization clearly. Both ADOT stations and private stations charge the same state-set fee: $20 for most gasoline vehicles and $30 for diesel vehicles.

Bring your vehicle registration and a valid photo ID when you arrive. The test itself takes about 10 to 15 minutes. The technician will connect your vehicle to a dynamometer (a machine that measures exhaust output) and run it through a standardized test cycle.

What happens if your vehicle fails the test

If your vehicle fails, the testing station will give you a written report showing which emissions standards it did not meet. You have 30 days from the test date to repair the vehicle and return to the same testing facility for a retest. The retest is free — you do not pay the testing fee again.

Common reasons for failure include a faulty oxygen sensor, a malfunctioning catalytic converter, or an engine control light that is on. A repair shop can read your vehicle's diagnostic codes to identify the problem. Some repairs are inexpensive (under $100), while others can cost several hundred dollars.

If you cannot repair the vehicle within 30 days, you can request a one-time 30-day extension from ADOT. After that, you must pass the test to renew your registration. If you cannot pass after repairs, you may be able to register your vehicle under Arizona's Waiver Program, which allows registration of vehicles that have failed after a good-faith repair attempt — but this requires documentation from a repair shop and approval from ADOT.

Understanding the emissions test standards

Arizona uses the Inspection and Maintenance (I/M) 240 test for most gasoline vehicles. This test measures nitrogen oxides, carbon monoxide, and carbon dioxide while your vehicle runs on a dynamometer. The machine simulates city and highway driving conditions over about 10 minutes.

Diesel vehicles are tested using a different standard that measures particulate matter and opacity (how much light the exhaust blocks). Heavy-duty diesel vehicles may have different requirements than light-duty diesels.

Hybrid vehicles and plug-in hybrids are tested the same way as gasoline vehicles when they are in gasoline mode. The test does not measure electric-only operation.

Emissions testing and vehicle registration renewal

You must pass your emissions test before you can renew your vehicle registration. When you renew online, by mail, or in person at an Arizona Department of Motor Vehicles office, the system will check whether you have a passing test on file. If you do not, your registration renewal will be delayed until you pass.

The test result is valid for 60 days from the test date. Plan to get tested at least a few weeks before your registration expires so you have time to repair and retest if needed. You can get tested up to 60 days before your registration renewal date.

If your registration has already expired because you missed the emissions test important date, you can still get tested and renew. However, driving a vehicle with expired registration is illegal in Arizona, so do not delay.

Vehicles that do not need emissions testing

Electric vehicles are permanently exempt from emissions testing in Arizona. Vehicles registered outside Maricopa and Pima counties do not need testing, even if they are driven into those counties regularly.

Vehicles with a model year more than 40 years old are exempt. For example, in 2024, any vehicle model year 1984 or older does not need testing. This exemption changes each year as older vehicles reach the 40-year threshold.

New vehicles registered in Arizona for the first time have a 60-day grace period before they must be tested. Vehicles with fewer than 6,000 miles on the odometer may be exempt from their first test cycle, though this varies — check with your testing station or ADOT to confirm.

What to do if you move or sell your vehicle

If you move from a non-testing county to Maricopa or Pima County, your vehicle will need to pass an emissions test before your next registration renewal. Plan ahead so you are not caught without a passing test when renewal is due.

If you sell your vehicle to someone in Arizona, the new owner is responsible for emissions testing going forward. The test is tied to the vehicle, not the owner, so a passing test does not transfer to a new owner — the new owner must get their own test before renewing the registration in their name.

If you move out of a testing county, you will no longer need emissions testing for that vehicle, even if you move back later. However, you will need to pass a test again if you register the vehicle in a testing county in the future.

Frequently Asked Questions

Can I get my emissions test done before my registration expires?

Yes. You can get tested up to 60 days before your registration renewal date. The test result is valid for 60 days, so if you test early and then your registration expires, you will still have a valid passing test on file when you renew.

What if I fail the test and cannot afford to repair my vehicle?

If you make a good-faith repair attempt but the vehicle still fails, you may be able to register it under Arizona's Waiver Program. You will need documentation from a repair shop showing what was attempted. Contact ADOT or ask your testing station about the waiver process.

Do I need emissions testing if I only drive my vehicle occasionally?

Yes, if your vehicle is registered in Maricopa or Pima County and is model year 1975 or newer, you need testing every two years as part of registration renewal, regardless of how often you drive it.

What happens if I drive through a testing county but my vehicle is registered elsewhere?

You do not need an emissions test. Testing is based on where your vehicle is registered, not where you drive. However, if you move your registration to a testing county, you will need to pass a test before your next renewal.

Can I test my vehicle at a private shop instead of an ADOT station?

Yes. Any private testing station that holds an ADOT contract can perform your emissions test. The fee is the same at both ADOT stations and private stations, and the test result is equally valid for registration renewal.