Check Engine Light is off, but codes still show up...
 

So about a month ago, my check engine light came on (shortly after getting some gas). I took it to an Advance Auto and got them to code it. It took maybe 20 seconds and it showed I had two codes coming up.
P0705
P1491

I drove a few more days and my check engine light went off. I thought that with my luck, maybe the bulb had just blown. Nope, the bulb is fine as when I check my dashboard lights it comes on just fine. So I took my car back to Advance, the codes are still coming up but it took well over 60 seconds for the device to pull the codes. The employee and said they had never seen a vehicle take that long?
Since then I've cleaned the EGR valve multiple times. Checked all my hoses as best I could, and I still get the codes coming up at Advance but no check engine light is on. It's weird. The guy at Advance said that it may be that the codes are "hard codes" and the only way to reset them would be by pulling the battery cables for a few minutes (not sure how long exactly)???

Any clue why the codes may be coming up but my check engine light is off?

What year car, model trim level, 4 or 6 cylinders? You may want to add that to your signature.

When you turn the ignition switch to ON (II), does the Check Engine Light come on for a few seconds?

Sorry, my bad...
It's a 99 Accord LX 4 Cylinder.
Yes, the check engine light (and other lights) come on for a few seconds when I turn the switch on, then go away at the same time.

Those could be "old" codes. Have them cleared and drive the car and see what you get from there.

Okay. I've had problems in the past. A Honda tech at my local Honda place had told me that the best way to clear codes is to pull the battery cables for 30 minutes. Is that still the best way to clear "old codes" as well?

Yes that is one way, be sure you have the code for the radio if you have the factory/OE radio.

Again, since the light does not come on when the car is on - I'm going with the "old code" theory. Codes store in the ecu/pcm so until they are "cleared" they stay there.

Okay. Sounds good! Thank you for all the help!

I forgot to ask. How many miles/How long do I need to drive the car after I pull the battery cables before I could have emissions done (assuming no codes come up)?

I forgot about this yesterday. After you do the reset, you should let it relearn idle first. See the bottom part of the first post in this thread by Jim : https://www.hondaaccordforum.com/for...e-speed-38734/

Then for the readiness codes. That depends on "how you drive it". The one that will take the longest is the evap system.

Almost all of the others can be "set" by a few simple steps. See attached.....don't worry with the "connect scan tool".

How long do the evap systems take on average? I'm not a speed demon, but I live on roads that are 55+.