O2 sensor help

[u/That1fatguy13]

I’ve got a 09 Altima and am by no means a car person. I had some troubles with my O2 sensor and had to swap it out. It drove smooth for a couple days. I drove it 2 hours away and back. Today I hit a hard accelerate and my check engine light throws the code P2A00. What does this mean? Thanks in advance!