evap codes

[ccapehartusarmyINF.(ret)]

okay im a little confused i recently had codes p0440 p0452 and there was an excess of pressure everytime i took the fuel cap off and the fuel guage didnt read right and i recently replaced my water pump wich i had the batt disconnected and upon finishing the water pump i was planning on replacing hte evap canister but i noticed the code was gone as well as the fuel guage read right and no excess pressure undoing the fuel cap
anyone have this happen or having similar codes showing up