Emissions

Depending on the model year and mileage of your vehicle, emissions system repairs may be covered by the vehicle manufacturer. Vermont law requires that a vehicle’s entire emissions control system be warranted for a minimum of 3 years or 50,000 miles. Warranty coverage for the more expensive emissions control components is extended to at least 7 years or 70,000 miles, and the catalytic converter is covered up to 8 years or 80,000 miles. Some vehicles’ emissions control systems are warranted up to 15 years or 150,000 miles! Be sure to check your owner’s manual or warranty booklet!

The vehicle should be driven under a variety of normal operating conditions in order for the OBD system to become ready. These operating conditions include a mix of highway driving and stop and go, city type driving, and at least one overnight-off period. Your vehicle owner’s manual should provide more specific information on getting your vehicle’s OBD system ready. For more information on readiness, please visit: http://dec.vermont.gov/ sites/dec/files/aqc/ mobile-sources/ documents/ Readiness.pdf

If your vehicle’s OBD system is not ready, the inspection of the OBD system cannot be completed. While this does not necessarily mean that your vehicle has a problem, it does indicate that your vehicle’s OBD system has not yet completed it’s tests, and problems may be present, but not yet identified. A recently disconnected or discharged (run down) battery, or recent servicing using a scan tool are the most likely reasons for a vehicle’s OBD system being “not ready.” Note that there are a few vehicles which should not be rejected as “not ready”.

1. The vehicle’s OBD system connector has been removed or is otherwise not working properly. The OBD check cannot be completed if the connector is missing or is not working properly. 
2. The Malfunction Indicator Light does not illuminate at all when the ignition key is turned to the “on” position. When the vehicle’s OBD system detects a problem, it turns on the warning light to alert the driver to a problem. However, if the light cannot illuminate because the bulb has burned out or is otherwise not working, the driver would not be alerted to the problem. 

If your vehicle failed, it must be repaired in order to receive a new inspection sticker. Your vehicle should be repaired by a qualified, trained automotive service technician equipped with the appropriate diagnostic and repair tools. Depending on your vehicle’s age and mileage, repairs may be covered by the vehicle manufacturer’s warranty. Refer to your vehicle owner’s manual for specific information on warranty coverage.

First, the vehicle is checked to see if the Malfunction Indicator Light (commonly called the “check engine” or “service engine soon” light) on the instrument panel illuminates when the ignition key is turned to the “on” position and then when the engine is running. Next, an electronic device known as a scan tool is connected to the vehicle, and used to communicate with the vehicle’s on board computer.

Motor vehicles are the largest source of toxic and ozone-forming air pollutants in Vermont. While modern vehicles are getting much cleaner due to newer engine management technology and emission control components, emissions stay low only when all these systems are working properly. OBD technology helps to ensure that vehicles are operating as designed, and the OBD check ensures that the vehicle’s OBD system is doing its job. 

OBD technology was developed in the 1980s by vehicle manufacturers to help technicians diagnose and service the computerized engine management systems of modern vehicles. A new generation of OBD (often referred to as OBD II) is present on 1996 and newer vehicles. OBD II monitors all components of the engine management system and can detect a malfunction or deterioration of these components usually well before the driver becomes aware of any problem.