Engine light with new cone filter

Hey everyone,
Just replaced my old stock airbox with a new cone filter. I had to do a little remod, but I love the sound! Last night when I installed it, everything was fine, but this morning when I started to drive it, the check engine light came on. I looked through the forum, and I know that I need to disconnect the batter cable after taking off the oxygen sensor, but do I need to leave it off? (Probably a stupid question, but ya know) And if I do, will it have an overall negative impact on my car? BTW it is a 1999 max GLE.
Thanks guys,
T.R. :rolleyes:

Does the 99 Max have the screw at the ECU to reset the CEL? If you do than reset it that way. If not, then i'm not too sure. Just make sure all of your sensors are connected that were originally connected at the stock air box.