Welcome to the Connecticut Emissions Program

Depending on the vehicle model year, make, fuel type, and gross vehicle weight rating (GVWR), your vehicle will receive one of the following tests; however, all vehicles are subject to the visual verification of the catalytic converter (visual inspection):

On-Board Diagnostic (OBD) Test – Most 1996 and newer vehicles have a standardized computer system called On-Board Diagnostic or OBD; as such, the most common emissions test procedure is the OBD test. An emissions testing inspector will connect a communication cable from the emissions analyzer to the Diagnostic Link Connector (DLC) in your vehicle. The emissions analyzer will only request data from your vehicle’s computer system. The information collected from your vehicle is recorded as part of your test record and evaluated by the emissions analyzer. Please click here for more information on OBD systems and test procedures.

Pre-Condition Two-Speed Idle (PCTSI) Test – 2007 and older non-diesel vehicles with the GVWR between 8,501 LBS to 10,000 LBS, will receive the PC TSI test. During this emissions test, the analyzer will measure tailpipe emissions (carbon monoxide/hydrocarbons). This test will also include the Gas Cap Pressure Leak Test.

Modified Snap Acceleration (MSA) Opacity Test – All 1996 diesel-powered vehicles or 2006 and older diesel-powered vehicles with the GVWR between 8,501 LBS to 10,000 LBS, will receive the MSA test. This test utilizes an opacity meter, which measures the smoke density emitted from your vehicle’s tailpipe. Please note that only Full-Service Test Centers can perform the MSA test.

More information regarding the different tests can be found under the Test Procedures tab.