They basically hook up under the dash run aprogram thats hooked directly to Albany and check all sensors to see if all are in a ready state.
On-Board Diagnostics Generation II (OBDII) Inspection. Most 1996 or newer gasoline-powered vehicles and most 1997 or newer diesel-powered vehicles that have a gross vehicle weight rating (GVWR) less than 8,501 pounds are subject to the OBDII emissions inspection. This test examines the Malfunction Indicator Lamp (MIL), also known as the "check engine" light, for operation/illumination, and verifies the test results of the vehicle's "on-board emissions diagnostic" system.
Low Enhanced Inspection. A "Low Enhanced" emissions inspection is required for most other vehicles, unless they are subject to the OBDII test or are exempt from all emissions inspections. This inspection is required for all vehicles from and including model year 1995 and older, through and including vehicles that are up to 25 model years old, and that weigh 18,000 lbs. or less.
Each emissions inspection for gasoline-powered vehicles confirms the presence and connection of the vehicle's required emissions control devices. This includes making sure that the vehicle's gas cap is present, is in good condition, and fits properly.
The following emissions control devices are examined if the vehicle was originally manufactured with them:
Catalytic converter (CAT)
Exhaust gas recirculation valve (EGR
Positive crankcase ventilation system (PCV)
Air injection system (AIS)
Evaporative emissions control (EVAP)
Fuel inlet restrictor (FIR)
Thermostatic air cleaner (TAC)
You can help your vehicle pass an OBDII emissions inspection by keeping it properly maintained. If the vehicle's Malfunction Indicator Lamp (MIL, or "check engine" light) indicates there may be a malfunction or other problem, have the vehicle properly repaired. A well maintained, properly functioning vehicle uses less fuel and creates less exhaust emissions.
