Hi, jjohnson86, what happened after you installed the new Denso sensor, I have a 2005 Honda accord, happened exactly the same as your wife's, first P0141 then after replaced showed P0139, please let me know.

 

jorge8421, nobody answered yet, so I'll add my experience with the codes. Since the replacement of the downstream 02 sensor with a Denso unit, my wife's 05 hasn't had any more codes come back. I've also done this replacement on several other Hondas at my work. None of them came back with any more codes. I'm sure there will be a rare exception now and then with some other issue, but for this repair, so far so good. Hope this helps!
-R

 

Poor performance likely means a steady unchanging low or high voltage as steady voltage around 0.5v is what you want for secondary O2 sensor. This suggests a short or open in the signal or ground wire.

A scanner w/ data display would confirm performance.

good luck

 

I'll check it out with my Matco MaxMe tool, I'm new trying to learn how to troubleshoot my family cars, so I will test it this weekend, thanks again.