So winter is over and hopefully so is this "issue". Never got around to changing out the O2 sensor. After cleaning of the MAP along with a few other things, the incidence of this "unusual code" basically disappeared. I suspect as MRRSM had indicated that it is perhaps an "abnormality" associated with the MAP. In some of internet "trails", there appears to be a potential of a GM firmware update which I am thinking perhaps changes what causes the code and maybe even "correctly reports" what it should be.... but that is a guess. I am hoping that it doesn't come back or if it does, does so during better climate conditions.