Visual Inspection

• Before you go through the emissions testing, you will have to pass a visual inspection to make sure there are no fluid leaks. In the case of a leak, it must be repaired first before you can move on to the emissions testing. You must have a valid registration and matching VIN (vehicle identification number). The fee for inspection in Massachusetts is 29 dollars.
  
  

Emissions

• There are two types of emissions testing in Massachusetts. The On-Board Diagnostic test (OBD) is for a majority of vehicles and the Snap Acceleration Opacity is for large, heavy-duty vehicles that don't have an OBD system. The OBD test is done by connecting your vehicle's computer to the station's analyzer and produces the emissions data in about three minutes.
  
  

Failing Inspection

• If you fail inspection, there could be a problem with your emissions system. If this is the case, you will usually be alerted by the "check engine" light. Some of the common causes are the EGR valve, the PCV valve, the air pump or the catalytic converter. You will need to make any necessary repairs before your car will pass inspection. The Vehicle Inspection Report (VIR) will give a mechanic the information necessary for the proper repairs.
  
  

Passing Inspection

• Once your vehicle passes the safety inspection and the emissions testing, you will be given a new sticker to put on the windshield that will be valid for one year.