What emissions testing means in Aurora

Aurora requires emissions testing as part of vehicle registration renewal. The test measures what your vehicle's exhaust contains — primarily nitrogen oxides, particulate matter, and hydrocarbons — to confirm it meets Colorado air quality standards. You cannot renew your registration without a passing test result, with limited exceptions for new vehicles and certain older models.

The test itself takes 10 to 15 minutes and costs between $25 and $35 depending on the testing facility. You drive to a state-certified emissions testing station, a technician connects a probe to your vehicle's diagnostic port, and the machine reads what your engine is producing. The result is either a pass, a fail, or a conditional pass (meaning you can drive to a repair shop but must retest after repairs).

Key Takeaways

  • Aurora emissions testing is required every two years for most vehicles and costs $25 to $35 per test at a state-certified station.
  • You need a passing test result before you can renew your vehicle registration with the Colorado Division of Motor Vehicles.
  • Vehicles from 1975 and earlier, and some newer electric or hybrid models, are exempt from testing requirements.
  • A failed test does not prevent you from driving to a repair shop, but you must retest within 30 days to complete registration renewal.
  • Testing stations are located throughout Aurora and accept walk-ins, though appointment availability varies by location.

When you need an emissions test in Aurora

You need a test when you renew your vehicle registration. In Colorado, most vehicles require testing every two years. If your registration expires in an odd-numbered year, you test that year; if it expires in an even-numbered year, you test that year. The Colorado Division of Motor Vehicles will not process your renewal without a passing test result on file.

You can take the test up to 120 days before your registration expires. This means you can test early and hold the result while you handle other renewal paperwork. If you fail the test, you have 30 days to repair your vehicle and retest before your registration officially expires.

Where to find emissions testing stations in Aurora

The Colorado Department of Public Health and Environment maintains a searchable list of all state-certified testing stations. You can search by city or ZIP code on their website to find stations near you. Aurora has multiple stations, including independent repair shops, quick-lube facilities, and dedicated emissions testing centers.

Most stations accept walk-ins during business hours, though wait times vary. Some stations offer online appointment booking, which can reduce your time on-site. Call ahead if you want to confirm hours or ask whether they accept your vehicle type — a few stations do not test diesel vehicles or certain commercial trucks.

What happens during the test

When you arrive, bring your vehicle registration and a valid ID. The technician will ask for your odometer reading and confirm your vehicle's year, make, and model. They will then connect a probe to your vehicle's on-board diagnostic (OBD) port, usually located under the steering column or dashboard.

The machine runs a series of readings while your engine idles and revs slightly. The whole process takes 10 to 15 minutes. You will see results on a screen at the station — either a pass, a fail, or a conditional pass. The station prints a receipt and sends the result electronically to the Colorado Division of Motor Vehicles within 24 hours.

Understanding a failed test and your repair options

If your vehicle fails, the test report will show which emissions standards it exceeded. Common reasons for failure include a faulty oxygen sensor, a loose gas cap, a failing catalytic converter, or engine timing problems. The report does not tell you which part to fix — that requires a mechanic's diagnosis.

You can drive to a repair shop when ready after a failed test. Colorado law allows you to operate the vehicle for 30 days after a failed test specifically to reach a repair facility and return for retesting. Keep your failed test receipt in case you are stopped by law enforcement. After repairs, schedule a retest at any certified station. If you pass the second test, the result goes to the Division of Motor Vehicles and your registration renewal can proceed.

Vehicles exempt from Aurora emissions testing

Vehicles manufactured in 1975 or earlier do not require testing. Certain newer vehicles also may have access to for exemptions: electric vehicles, plug-in hybrids, and vehicles that have been registered in Colorado for less than two years are exempt. Diesel vehicles registered before 1997 may be exempt depending on their weight and registration class.

If your vehicle falls into an exempt category, you still need to indicate that on your registration renewal form. The Colorado Division of Motor Vehicles will not automatically waive the requirement — you must declare the exemption yourself. If you are unsure whether your vehicle qualifies, contact the Division or ask the testing station when you call.

How to renew your registration after passing the test

Once you have a passing test result, you can renew your registration online through the Colorado Division of Motor Vehicles website, by mail, or in person at an Aurora county clerk's office. The test result is transmitted electronically to the state system within 24 hours, so you do not need to carry the paper receipt — the system will show your pass automatically.

You will need your vehicle identification number (VIN), current registration, proof of insurance, and payment for renewal fees. Renewal fees vary based on your vehicle's age and weight. You can complete the entire process online if you have a valid Colorado driver's license and current insurance information on file.

Frequently Asked Questions

Can I renew my registration before I take the emissions test?

No. The Colorado Division of Motor Vehicles will reject your renewal process if no passing test result is on file. You must test first, receive a pass, and then complete registration renewal. You can test up to 120 days early, so you can take the test and then handle registration paperwork whenever you have time.

What if I fail the test twice?

You have 30 days from the first failed test to retest. If you fail a second time, you cannot renew your registration until you pass. At that point, you will need to decide whether to invest in repairs or explore other options with a mechanic. Some repair shops offer diagnostic services specifically for emissions failures and can identify the cheapest fix.

Do I need an appointment or can I just walk in?

Most Aurora testing stations accept walk-ins during business hours, though wait times can range from 15 minutes to over an hour depending on the time of day and station. Some stations offer online appointment booking, which guarantees a shorter wait. Call the station you plan to visit to ask about their current wait times and whether appointments are available.

What if my vehicle is too old to have an OBD port?

Vehicles manufactured before 1996 do not have an OBD port and cannot be tested using the standard electronic method. These vehicles may be exempt from testing entirely, or they may require a different type of test depending on their year and registration class. Contact the Colorado Department of Public Health and Environment or ask at a testing station about your specific vehicle.

Can I test in a different Colorado city and use the result in Aurora?

Yes. Emissions test results are valid statewide in Colorado. If you test in Denver, Boulder, or any other city, the result will appear in the state system and you can renew your Aurora registration based on that test. The test result is tied to your vehicle's VIN, not to the location where you tested.