Emissions Testing in Arizona

Who Needs an Emissions Test or Smog Check

In Phoenix, gasoline vehicles from model year 1967 and newer must pass an emissions test if registered in the testing area. In Tucson, the requirement applies to vehicles from model year 1967 and newer as well. Diesel vehicles are also subject to testing. Exemptions apply to vehicles within the first five model years, motorcycles, electric vehicles, and those registered outside the designated areas. Heavy-duty vehicles over 8,500 pounds may have different testing protocols.

How Often Tests Are Required

Testing frequency depends on vehicle age and registration area. In Phoenix, gasoline vehicles from 1981 and newer under 8,500 pounds test every two years. Older gasoline vehicles and all diesel vehicles test annually. In Tucson, gasoline vehicles from 1996 and newer under 8,500 pounds test every two years. Older vehicles and diesels test annually. Testing is tied to registration renewal.

Where Emissions Testing Is Required

Emissions testing is required only in two designated areas. Area A covers the Phoenix metropolitan region within Maricopa County. Area B covers the Tucson metropolitan region within Pima County. Vehicles registered outside these boundaries do not require testing. The exact boundaries are determined by zip code and can be verified through the Arizona Department of Environmental Quality.

What Happens During the Test

Testing is conducted at state-operated emissions stations. For vehicles from 1996 and newer under 8,500 pounds, an OBD-II diagnostic test is performed. The technician connects to the vehicle's diagnostic port to read fault codes and check readiness monitors. Older vehicles may undergo a dynamometer test or tailpipe emissions measurement. Diesel vehicles receive opacity testing. Technicians also perform a visual inspection for tampered or missing emissions equipment including the catalytic converter and gas cap.

Areas in Arizona That Require Emissions Testing

Arizona requires emissions testing only in the Phoenix and Tucson metro areas. In Maricopa County, cities such as Phoenix, Scottsdale, Mesa, Tempe, Chandler, and Glendale fall within the testing boundary. In Pima County, the Tucson area including Oro Valley and Marana is covered. Emissions testing locations in Arizona are concentrated in these urban centers with multiple state-operated stations. Rural areas and cities outside these counties, including Flagstaff, Yuma, Prescott, and Sierra Vista, have no testing requirements. Testing boundaries are defined by zip code, so drivers should verify their registration address against the official boundary map.

How the Emissions Test Works in Arizona

The emissions test at an Arizona state station typically takes 10 to 20 minutes. Bring your vehicle registration. No appointment is needed at most stations. For 1996 and newer vehicles under 8,500 pounds, the technician performs an OBD-II scan by connecting to your diagnostic port. They check for stored fault codes and verify readiness monitors are complete. The check engine light must be off. Older vehicles from 1981 to 1995 may undergo the IM 147 dynamometer test, which simulates driving while measuring exhaust output. Pre-1981 vehicles take a two-speed idle test. Diesel vehicles receive a smoke opacity test. Common failure reasons include a lit check engine light, incomplete readiness monitors, or failing emissions components. State fees are regulated and range from approximately $12 to $25 depending on vehicle type and test area. If your vehicle fails, you have 60 days to complete repairs and return for a free retest.