reset computer on '01 Sierra 5.3L?

I have an '01 Sierra 5.3L. I put Gibson headers, pro-comp air intake w/ a k&n filter, and a Granatelli MAF sensor. the service engine soon light has come on saying that both right bank and left bank are running too lean. For some reason the computer is not resetting itself just by taking the neg. battery cable off. Is there anything I can do? Thanks for any anticipated help!!!!!!!!!

The PCM is set up to read sensors in certain parameters..with the addition of your aftermarket goodies, did you reprogram the PCM to read your changes?
The PCM does not recconize the changes and sees a fault...I would recommend calling Hypertec and as them for a calibration change to meet your new changes.