The Division of Motor Vehicles performs two types of exhaust emissions analysis. The first is an idle and the second is a two-speed (2,500 rpm's). These tests enable Delaware to comply with the Federal Clean Air Act requirements for vehicle emissions testing. Emissions Testing

Inspection Tips:

The Division requests that customers perform the following items upon entering the vehicle inspection building:

Ensure your automatic transmission is in 'Park', or 'Neutral' and have your insurance and vehicle registration card present.

Vehicle Year Type of Inspection
1967 & Older passenger vehicles No Emissions test performed
1968 – 1980 vehicles Idle Test
1981 – 1995 Two-Speed Test
1996 – To current five model year On-Board Diagnostic (OBDII)
Current five model years Exempt
  • Idle Emission Test– The DMV technician places the probe into the tailpipe to begin test. This test takes approximately 1 minute to complete.
  • Two-Speed Test- The DMV technician will place the RPM sensor on the vehicle’s hood prior to beginning phase one of the test. Phase two the DMV technician will request that you increase the engine speed to 2,500 rpm. DMV shall not test emissions at a higher engine speed. To guide you through this process, the DMV technician shall direct you to follow the guidelines on the computer monitor located outside the driver’s door. The monitor shows your engine speed and indicates when you are in the acceptable range. This test takes approximately 2.5 minutes to complete.
  • On-Board Diagnostic (OBDII) - There are two steps in the OBD II inspection. With the key on and the engine off, the inspector confirms that the MIL is functional. The inspector connects the inspection tool to the OBD II system to check the status of the system. The following is a typical OBD II connector. This test takes approximately 2 minutes to complete. The test checks for trouble codes and monitor readiness. If you have recently replaced your battery the vehicle's monitors will not be ready causing the vehicle to fail. Drive the vehicle for several days to reset the monitors prior to DMV testing. The OBDII test method will replace the Division's tailpipe test (and pressure test) for 1996 and new gasoline powered vehicles and 1997 and new diesel powered vehicles with MGVWR less than 8,500 pounds registered in New Castle County and Kent County.
    For additional information regarding OBD II, please feel free to access the following web sites:

    OBD Diagnostic Trouble Codes

    Colorado State University

    Weber State University OBD II Clearing House
    OBD location
Please Follow These Instructions
DMV Takes Safety Seriously
DMV Technicians will be in front of, in the rear of, and under the hood of your vehicle (or in the driver or passenger side of the vehicle while it is operating) when performing these tests.
If you are unsure about any instruction given, do nothing and ask for assistance.
DMV Technicians will assist those customers having any problems completing a portion of Delaware's inspection program.
Remember – Smoking and cell phone usage is prohibited in the inspection lanes. No pets are allowed in the inspection facilities.