2003 Elantra check engine light/emissions test question

If it has not come back on you will have no problems. Things like an improperly attached gas tank cap will cause the CEL to light and then after you fix the cap problem the light will go out. This is normal operation. It does no good to disconnect batteries, clear codes with scanners, etc. Anything you can "fix" or "hide" by doing this is not a real code in the first place and not something they are going to fail you for. The things you will get failed for can't be cheated by these simple techniques.

Just go ahead and get your car inspected and head out for a relaxing drive.

Actually, the lamp being previously on can present a problem. Although the condition has corrected itself and the lamp has turned itself off, the code may still remain. It takes much longer to eliminate the code than to clear the lamp. To my knowledge, any stored code will fail an OBD-II test. If you're not planning on addressing the reason the lamp was on, disconnecting the battery now (at least a week prior to the test) is probably your best bet. You'll need to do significant driving for all the monitors (self-tests) to run. After all the basic monitors run, others will require steady-speed highway driving. If too many monitors haven't run, the emissions facility won't certify your vehicle.

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Will the stored code dictate a failure if all the monitors report?

I just checked with my daughter as she was getting ready for work and confirmed something that was in the back of my mind. She had gotten her car inspected within a couple of days of a CEL that was generated by a gas cap seal. When she took the car in the CEL was off but I had never cleared the light - it just cycled itself off. Car passed inspection fine. We're in NY state and other states may have varying laws on how they look at past codes, but NY seems to care that the light is on now, and not that it was on in the past.

I'm in the DC metro area, and I see numerous cars which fail with some oddball trouble code that has probably not been active for quite some time that have failed emissions. In my area here's what seems to be cause for failure:

1. Check engine lamp on
2. Check engine lamp not functional
3. Any stored Pxxxx trouble code
4. One or more (depending on model year) monitors not run.

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That makes sense - the first two are at the heart of the matter - any state that does this testing now will not pass a car with a CEL on, or a burned out lamp. Likewise, if the monitors have not run they will fail the car. This is how they stop people from clearing a CEL and running quickly to get an inspection. Any stored P code is going to turn on the CEL anyway, right?

So we're pretty much back to what I said in my original response.

It won't necessarily turn on the lamp. I've seen several cars with transmission-related codes that haven't turned the lamp on.

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Ahhhh - good point. So in MD you'd have to fail the car for inspection for a stored tranny code? I'm 99.9% certain we aren't that stiff up here in NY.

I see cars from three jurisdictions, so I'm not sure whether all use the same criteria. In Maryland and DC, a state contractor runs the emissions facilities. In VA, they're independent. I recall seeing the failures for tranny codes from DC. Don't recall if I've seen any from MD. Remember none from VA. (Actually, I think VA still does a tailpipe test of some sort for all vehicles, so OBD codes probably have no bearing there).

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Thanks all for your input. I took the Elantra in for obd emissions testing this morning with no problems. I did disconnect and reconnect the battery last Saturday just in case. I'm in the Chicago area by the way. It's great to get in and out of the testing centers so fast now with the obd hook-ups instead of the tail pipe/treadmill tests they used to do that took quite some time and could be problamatic with the techs in your car doing the testing (sounding like the engine was going to blow they would rev them so high).

Thanks aga>I see cars from three jurisdictions, so I'm not sure whether all use the