The local Honda dealer has replaced my secondary O2 sensor 3 times in the last 3 months - Nov/2012, Dec/2012 and Jan/2013. Each time the result is the same.

P0139 02 Sensor #2 slow response

They don't know why. They told me to pick one of the following to replace and they aren't sure which, if either, will fix the problem.

• replace the Primary O2 Sensor
• replace the Catalytic Converter.

2005 Accord LX
98,700 miles

Poked around the net and checked the following as a result.

I don't smell anything like rotten eggs from Catalytic Converter.
It doesn't seem to have performance issue and no stalling.
I examined engine and it doesn't have any wet spots.
I don't hear any hissing sounds or leaks.

Anyone have any thoughts on what I can check or do?

 

check connectors for o2 sensor. sometimes they can get damaged and not make a current or poor current.

 

I wouldn't pick either.....my vote, refund your money and take is somewhere else....but that is me.

 

totally concur! I'm hoping you have not been paying for each of their "experiments" of throwing parts at this car.

 

Its the gas cap. Make sure u turn it at least 3x. Everytime my light comes on it reads that code and after tightening cap within 70mi it goes off. Its usually comes on when gas is a little less or little over half tank of gas. Light will also come on if u get gas while car is running