2003 Elantra check engine light/emissions test question

I have a 2003 Elantra. A couple of months ago the check engine light came on
for a couple of days and then went out on it's own. The car runs fine and
the indicator lamp works as it should when starting the car. I have to have
obd emissions test done and I am wondering if the light having come on
previously would cause it to fail because of a stored code or since the
condition corrected itself and has cycled through enough that it's not a
problem. Should I disconnect the battery to reset the computer and drive it
for a week before I get it tested? Thanks for any help.

 

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.

 

Thank you much. You confirmed what I thought. I appreciate your response.

 

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.

 

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.

 

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).

 

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 again.