What you need to know about Aurora emissions tests

Aurora requires emissions testing as part of your vehicle registration renewal, but only for vehicles model year 1981 and newer. The test measures what your tailpipe produces — carbon monoxide, nitrogen oxides, and particulate matter — and costs between $20 and $30 depending on which testing station you choose. You can get tested at any Colorado Department of Revenue-approved emissions testing facility in the Aurora area; the state does not require you to use a specific location.

The test itself takes about 10 minutes. Your vehicle sits on a dynamometer (a machine that measures engine output) while equipment reads your emissions. If you pass, you get a certificate when ready and can complete your registration. If you fail, you have 60 days to fix the problem and retest at no additional charge at the same station.

Key Takeaways

  • Aurora emissions testing is required for all vehicles model year 1981 and newer during registration renewal, and costs $20 to $30 per test.
  • You can visit any state-approved testing station in the Aurora area; the Colorado Department of Revenue website lists all current locations.
  • A passing test takes about 10 minutes and gives you a certificate you need to complete your vehicle registration.
  • If you fail, you have 60 days to repair your vehicle and retest for free at the same station before your registration expires.

Finding an approved testing station in Aurora

The Colorado Department of Revenue maintains a searchable list of all approved emissions testing stations on its website. You can filter by county (Arapahoe County for Aurora) and see each station's address, phone number, and hours. Most stations are open Monday through Friday during business hours, with some offering Saturday appointments.

Call ahead before you go. Testing stations sometimes have wait times, especially during peak registration renewal periods (late summer and fall). Some stations accept walk-ins; others require appointments. A few stations in the Aurora area also perform safety inspections at the same visit, which can save you a trip if your vehicle needs both tests.

What happens if your vehicle fails the emissions test

A failure means your vehicle produced emissions above the state limit for at least one pollutant. The testing station gives you a printed report showing which pollutants exceeded limits and by how much. Common causes include a faulty oxygen sensor, a malfunctioning catalytic converter, or an engine that is running too rich (burning too much fuel).

You have 60 days from the test date to repair your vehicle and return to the same station for a free retest. You do not need to pay again. If you pass the retest, the station issues a new certificate and you can register your vehicle. If you fail again, you can retest once more within the 60-day window at no cost. After 60 days, you must pay for a new test.

Preparing your vehicle before testing

Before you schedule a test, make sure your vehicle has been driven for at least 20 minutes so the engine reaches normal operating temperature. A cold engine can produce higher emissions readings and cause a failure even if the vehicle would pass when warm. Also check that your gas cap is tight and not damaged — a loose or broken cap can trigger a check engine light and cause a test failure.

If your check engine light is already on, you can still be tested, but the vehicle will likely fail. Have a mechanic scan the engine code before you test. Many auto parts stores scan codes for free. Common codes that cause test failures — like oxygen sensor faults or catalytic converter issues — are usually fixable within a few hundred dollars.

Registration important date and testing timing

Your emissions test is valid for 120 days from the test date. Plan your test so the certificate does not expire before you complete your registration renewal. If your registration expires on a specific date, test no earlier than 120 days before that date.

You can test and register online or by mail, but you must have a passing emissions certificate or a valid waiver before the state will renew your registration. If you test after your registration has already expired, you are driving with an expired registration, which can result in a traffic stop and fine. Test before your renewal important date, not after.

Waivers and exemptions from testing

Some vehicles are exempt from emissions testing. Diesel vehicles, motorcycles, and vehicles model year 1980 and older do not require testing in Aurora. Vehicles that are less than six model years old may be exempt depending on the specific year and your vehicle's history.

If your vehicle fails twice and the repairs would cost more than $500, you may be able to get a waiver. The testing station can provide a waiver process, but you must have documentation of the repair attempts and costs. A waiver lets you register your vehicle for one year without a passing test, but you must retest the following year.

Frequently Asked Questions

Can I test my vehicle before my registration expires?

Yes. Your test is valid for 120 days, so you can test up to four months before your registration renewal date. Testing early gives you time to fix any problems and retest if needed before your registration expires.

What if I move out of Aurora after I test but before I register?

An Aurora emissions certificate is valid in any Colorado county. You can test in Aurora and register your vehicle in any other Colorado county using the same certificate, as long as the certificate has not expired.

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

It depends on the station. Call ahead to ask whether the station accepts walk-ins or requires appointments. During busy seasons, wait times can be 30 minutes to an hour even with an appointment.

What if my vehicle has a check engine light but I pass the test?

You can pass the emissions test even with a check engine light on, though it is less common. The light means a fault code is stored, but if your actual emissions are within limits, you pass. Have a mechanic scan the code anyway to understand what triggered it.

Can I register my vehicle without an emissions test?

No, unless your vehicle is exempt (diesel, motorcycle, or model year 1980 or older). The state will not process your registration renewal without a passing test certificate or an approved waiver.