Why I replaced front oxygen sensor for my Honda Accord but check engine light is still on

Question

OBD II said : o2 sensor circuit band1 sensor1
i have already replaced an upstream oxygen sensor [Denso brand] but check engine light is still on.

Answer 1

P0135 if the 02 sensor leads have a poor connection this would set the code . it the harness that has to be thoroughly check for any open circuit, You need to rule that area out, P0135 when a Honda set this code it usually the ECM at fault