I have a 2004 Honda Accord EX V6. 236K miles.
CEL came on and gave multiple codes all pointing to the Bank 2, Sensor 1 O2 sensor.
Purchased and replaced the unit last week. CEL remained on. When I checked it, same codes. I erased the codes, but the CEL returned.
I replaced this same O2 sensor in November 2014.
In speaking with others, recommended using dielectric grease on the connection.

Any other suggestions?