HONDA P CODES (POWERTRAIN) P0400 - P0499 P0420

I Am Stumped, I Used A Scanner To Read The Code And Then Erased It Two Days Ago. I Figured It Would Come Back Since It Is Low Catalyst...

I Have A 2000 Honda Odyssey Ex 124000 Miles With Automatic Transmission. I Am Assuming My Problem Is With O2 Sensor On Bank 1, My Question...