How is the OBD used during a state-required inspection?
State inspections vary from state to state and you should get any detailed inspection guidelines from the state you reside in. This article is for general guidelines of what the inspection of the vehicle onboard diagnostic (OBD) system is used for during the inspection.
If your state inspection test includes hooking up to your OBD connector, then the test is going to look to see if you have active codes in your computer and if all the emission monitors are passed in your system. If your vehicle has any codes in the system, it will fail you on the test. If you have no codes but have emission monitors that have not passed yet, then you will fail as well.
If you used your own scanner or had your vehicle scanned recently and the codes were cleared, then it will also clear the emission monitors. The emission monitors are a list of computer systems that pertain to the emissions of your vehicle. The computer systems are monitored and tested during a single or multiple drive cycles and either pass them or fail them, then put the Check Engine Light on with a code to the system. Some of the possible systems monitored are: engine misfires, catalyst, oxygen sensor, fuel system, EGR system, VVT system, EVAP system, secondary air injection, or other systems that the vehicle uses to control emissions. Diesel engines may have additional monitors that gasoline engines do not have. Just clearing a engine code and trying to get an inspection cannot be done since the monitor system will not pass if there is a problem in the system.
If you have a Check Engine Light on and cannot pass emission tests due to codes appearing or failing system monitors, then you should have a mechanic diagnose and repair the systems for you.
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