Dominick

If your state uses High Enhanced OBDII inspections standards you can only fail for a few reasons which I will list below. But keep in mind that the vehicle still has to pass the safety portion first, and unless you have a cool inspector you will automatically fail for no Cats.

Your vehicle can only fail a high enhanced OBDII inspection if...

1) The DLC on the vehicle is broken or absent. If the inspection computer can't connect to your vehicles PCM through the OBDII Data Link Connector, or if it's been removed, then you won't pass.

2) The OBDII malfunction indicator light (MIL) on the vehicle does not illuminate when the ignition is set to the ON position and the engine is not running(KOEO). This is only a problem if you removed the MIL bulb, or the bulb itself -or circuit- went bad.

3) The MIL remains illuminated when the engine is in running(KOER).

4) Too many 'Non Continuous' OBDII monitors' on the vehicle report that they are Not Ready at the time of the inspection. -More on OBDII monitors below, and how they effect high enhanced OBDII inspections.


There are 11 total OBDII Monitors. They come in only two flavors..Continuous(3 total) and Non Continuous(8 total). They are basically a system check for the emissions components that are installed in your vehicle. On average, an OBDII compliant vehicle will have 8 monitors total -including the three continuous monitors-. After the inspection computer looks for trouble codes stored in your PCM, it checks the readiness status of the OBDII monitors and automatically fails a vehicle if too many monitors are listed as 'Not Ready.'

When you clear the MIL, or disconnect the battery, it will automatically reset ALL the Non Continuous OBDII monitors to Not Ready. That's enough to fail any vehicle. In order to pass inspection, each monitor will now have to run and pass before they will show up as Ready. This is done when a trip(aka Drive Cycle) is completed. The criteria for a Drive Cycle is very specific, and varies for each monitor. Some can be especially difficult to complete due to the exact steps and conditions needed to run the monitor. Monitors can take minutes, hours, days, or even weeks to complete running under normal driving conditions, so you don't want to clear a MIL, or disconnect the battery before a high enhanced OBDII inspection. If you have a problem that tripped a code and illuminated the MIL you need to fix the problem first and then drive the car until you have enough monitors ready or you won't pass.

NOTE: Depending on the year of your car, you DON'T need ALL Monitors Ready to pass. For example a '96-'00 can have two monitors Not Ready and still pass. So if you have a '96-'00 Mustang and all your monitors run to completion and show as ready except for Cat and O2, you can still pass.

20001 and newer vehicles can only have one monitor not ready and still pass.