How it Works

Inspection Process

In Colorado, state regulation does not require safety inspections (tire pressure, headlights, etc.). However, your vehicle will be subject to a brief visual check to ensure that it does not have any visible conditions that would make it unsafe to evaluate. Inspectors will look for obvious fluid leaks, worn tires, etc. If your vehicle is rejected for further evaluation for safety or other reasons, you will be given an 'Unable to Test' form stating what condition(s) must be corrected before an inspection can be performed.

All vehicles are checked for items like illuminated dashboard warning lights, the presence of gas caps and tire pressure. Vehicles also are checked for required components (these may vary depending upon the make and model) to ensure that they are installed, intact and in working order. These include catalytic converters, air injection systems and oxygen sensors.

Vehicles not originally equipped with these components are not required to have them. However, a vehicle's original equipment must be present and unaltered at the time of the emissions inspection. Please be advised that "gray market" vehicles and customer-built vehicles must either have all required components or present paperwork from a state-operated Emissions Technical Center documenting an exemption from this requirement.

Gas caps on all 1975-and-newer vehicles are tested for leakage. The gas cap will be removed and attached to a pressurization device to ensure that an adequate seal is preventing harmful emissions from escape into the atmosphere. Vehicles with faulty gas caps will fail the overall inspection. By law, faulty gas caps must be replaced and vehicles subsequently returned to an Air Care Colorado station to be fully inspected again. State of Colorado regulations require a FULL EMISSIONS INSPECTION be performed again because full vehicles may perform differently once a properly-sealed gas cap is installed.

The “Check Engine” light is a general term applied to various dashboard warning lights that indicate malfunctions or serve as maintenance reminders. Depending upon the make and model of your vehicle, the warning light may it say "Check Engine," "Service Engine," "Emissions," or may simply illuminate an image of an engine. In any case, a dashboard warning light that remains illuminated at the time of inspection will either result in a failed overall inspection or an advisory given to the motorist so that it may be properly addressed.

All vehicles will be checked for the presence of visible smoke. Vehicles emitting excessive visible smoke will fail the overall inspection. Be advised that, by law repairs for visible smoke are not considered part of the repair expenditures required to qualify for a waiver.

On-Board Diagnostics (OBD or OBD II) 'Plug-in' Test
refers to the computer-based systems built into all 1996-and-newer light-duty vehicles. OBD systems monitor the performance of a vehicle's major components, including those responsible for controlling emissions. OBD systems continuously check vehicles to ensure that they are operating as designed and to detect emissions-related problems before they might otherwise be noticed.

I/M 240 Dynamometer 'Treadmill' Test
refers to vehicles that are driven on a treadmill-like device that evaluates emissions under a series of simulated driving conditions.

Two-speed Idle (non driving) Test
vehicles that are model year 1981-and-older subject to this non-driving evaluation that monitors emissions at idle speeds.

How long do I have to get an inspection once I receive my registration renewal postcard?

There is a 30-day grace period for your annual or biennial emissions test upon expiration.  Simply, this means you have a month (30 days) after your tags expire to get an inspection.  However, keep in mind that more than 30 days past the expiration date could result in a $50 ticket. Requests for extensions beyond the 30-day grace period must be made through your local Motor Vehicle office.

Types of Tests

Depending upon the age and type of vehicle, the following tests are performed:

OBD is a non-driving test in which the vehicles on-board computer is connected to a computer at the Air Care Colorado facility that accesses various information.  This includes details about the "Check Engine" light, other dashboard indicators and codes that help determine emissions-related problems for quicker repair and improved performance.

The I/M240 is the "treadmill" test most commonly identified with emissions inspections in the Denver-metropolitan area and the North Front Range.  Vehicles are driven on a device known as a dynamometer that simulates a four-minute driving cycle under a variety of conditions (uphill, downhill, acceleration and more) to evaluate emissions.

This is the original type of test that evaluates emissions at two different idle speeds. It is used as part of the inspection for 1981-and-older vehicles.

Sometimes tests may not be performed as part of the overall inspection because the vehicle's configuration or onboard computer are preventing communication with the equipment at the Air Care Colorado facility.  Vehicles also may be selected randomly for ongoing program studies that are continually used by the State of Colorado for quality assurance purposes to evaluate overall program effectiveness.

Please note that vehicles with low-profile or over-sized tires/rims cannot be tested on standard dynamometers. In some cases two-wheel drive vehicles may be able to be tested on special dynamometers capable of testing vehicles with these unusual features. The Sheridan, Boulder, Ken Caryl, and Fort Collins stations are equpped with these dynamometers.These are the only stations in the program area equipped with specialized dynamometers that can test these vehicles.

A properly functioning gas cap is an essential part of the emissions control system of every vehicle.  Missing or leaking gas caps will cause vehicles to fail the emissions inspection.  A full retest is required if a vehicle fails an initial inspection for a missing or defective gas cap because the gas cap affects the overall emissions control capability.  The vehicle must be inspected completely with the new gas cap in place in order to be properly evaluated.

RapidScreen is an alternative to the inspection at an Air Care Colorado facility first used right here in Colorado!  RapidScreen utilizes data collection units placed roadside that can evaluate emissions as a vehicle drives by.  It is an alternative to the standard inspection and is used to identify vehicles that are operated exceptionally cleanly.  Please visit the RapidScreen page on this website for more information.

Inspection Reports

Motorists are given a Vehicle Inspection Report (VIR) upon completion of each inspection at an Air Care Colorado facility. The VIR contains information on the vehicle's performance on the various elements of the emissions inspection.

Below is a sample inspection report.

NOTE: You must provide your original Vehicle Inspection Report to the Motor Vehicle clerk when registering your vehicle. Some Motor Vehicle offices will not accept copies.

Test History Lookup

If your vehicle is not currently registered in the state of Colorado, a Vehicle Identification Number (VIN) verification is required prior to registration.  A VIN verification may be obtained at any Air Care Colorado inspection facility.  If your vehicle also requires an emissions inspection, simply let the inspector know that you also need a VIN verification at the time of inspection.  If your vehicle does not require an inspection, do not drive into the inspection lanes.  Simply ask for a VIN verification inside the office.  The VIN verification fee is $25. 

You may request the history of your last few qualifying passes by RapidScreen Roadside Testing units by clicking on the button below.