Check Engine Light and smogging

[CaliManDan]

My girlfriend has to get her car smogged in order to re-new her registration this month. The problem is that the check engine light on my girlfriend's car has always been off and on since the moment she bought it 1 1/2 years ago. We ran the codes once and it came back with something like loose gas cap but I think her check engine light is faulty. It will stay on for days at a time and then go off for days at a time.The problem is she has to get her car smogged tomorrow. I've heard that if the check engine light is even on the smog inspector will immediately fail the car. I was thinking about disconnecting the battery before we go and then re-connecting it because I figured that would erase all the memory codes and even though they would come back eventually...it would give us enough time to get the car smogged without the light being on. But I did some searches online and there are quite a few people saying if you disconnect the battery the car could lose all sorts of "memory stored functions" and could affect driveability and such.Any suggestions?

[DiveNut]

Disconnecting the battery will not affect drivability dramatically. The ECU will simply need some time to re-learn in order to run most efficiently and smoothly. Nothing to worry about there. However, I believe (though I may be wrong) some state testing facitilties may require at least 2 weeks of "history" on the ECU without a CEL when performing the test. If so, you may just need to clear the CEL and drive it for awhile before testing, assuming you don't throw the CEL again diring that time. But then again, I may be totally wrong

[danimal86]

^this is true. You'll need to drive you car for 50+ miles after the ECU has been reset.