How am im getting p0151 and p0152 codes at the same time on a new O2 sensor?

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So using an obd tool i got the code p0051 for my 2004 Legacy (35th Anniversary Edition) and subsequently changed the bank 2 O2 sensor 1. I am now getting a p0151 code which is low voltage for that brand new sensor. Strangely enough, in trying numerous possible solutions (cleaning the mass air filter sensor, checking for leaks, ect) and turning the code off hoping it will stay that way, i sometimes get a p0152 code, which means high voltage for that same sensor. how can i be getting both? and how do i get rid of them? any help would greatly be appreciated. Also since im new here if theres a better place to post this question let me know, thanks folks!