songkrai,
As a result of the federal Clean Air Act Amendments of 1990, newer more advanced OBD systems, known as OBD II, were built into all vehicles manufactured starting in 1996. OBD II systems monitor vehicle conditions and components that are related to vehicle emissions, such as the catalyst in the catalytic converter, engine misfire, the engine coolant temperature, and the oxygen sensor.
Therefore, beginning in 2005, as required by the federal Clean Air Act Amendments of 1990, New Hampshire's annual vehicle safety inspection will include a test of the OBD II system on all
1996 and newer passenger cars and light duty trucks.
If a shock absorber or strut is leaking, your vehicle
will fail inspection.
If your car fails inspection, the reasons will be printed out on the emissions test report. It will stay on that report until the problems are fixed.
http://des.nh.gov/organization/divis...sp/onboard.htm