mikey1

i am getting P0139 about every other day or so,

my CEL will come on with P0139 for about a day or two, then the light will turn off (on its own) for about a day or two, this cycle has been repeating for about a month,

from what im reading it seems like an O2 sensor issue?

Reverb2005

I was getting P0139 for a while too. I ended up changing the O2 sensor but noticed it would still return.

Turns out there is a Honda TSB about the issue.

www.civicforums.com/forums/attachment.php?attachmentid=77239&d=1252107997

So, it could either be the sensor, or you may need the computer upgrade. The upgrade was about the same cost as the sensor (~$40) so it is a hit or miss on that one. I mean, at least if you buy the sensor you have a new O2 sensor if it doesn't fix the problem.

ezone

Post your car info again?

mikey1

05 auto special edition 4 door

290,000 km

ezone

Rear O2 sensor -- slow response



That bulletin for software could apply to your car

Rear O2 sensor could be having issues

Exhaust leaks? We had a Hyundai the other day setting the same P0139 code, turned out to have a miniscule exhaust leak (bad gasket) in the joint between the cat and the next pipe that held the rear sensor.

mikey1

thanks,

so do you think it is unlikely to be the sensor itself?

is that software update a recall?.....will it be free at a dealer?

ezone

If I saw your car has the code and the sensor looks old, I'd replace the sensor AND plug our magic software box in and reflash the PCM if possible. One complete job, no comeback.

You know the drill, see who made it the sensor and get the same brand.

Not in the US.
You're having that bad dream again. Wake up!

mikey1

thanks,

is it worth trying to clean the sensor?

i have no idea what they go for?

Reverb2005

I haven't heard of anyone actually being able to clean the sensor and have it work properly again.

I got mine off Amazon (Denso brand, works perfectly) for literally $40 bucks. It is the O2 sensor, not the A/F sensor, so it is the cheap one!

You need the special removal tool too, so you can get the wire through the socket. However, I noticed that the sensor was not on too badly believe it or not. You could probably get away with a wrench...

The Denso sensor even comes with a little tube of anti-sieze!

I'm in Canada and I got charged $40 for the software upgrade.... Not terrible I guess...

ezone

^What he said^

No..

mikey1

thanks, i guess i will just buy one

mikey1

just wondering if there is any chance that bad gas could be causing this,

i have filled up at a different station twice now, and the light has not come back on, it would normally come on every other day or so, now its been a week......i guess i will wait and see

ezone

I would not expect it to be related to fuel quality.
I'd think something like that would show up as a running problem and/or affect the primary sensor instead of affecting only the post-cat sensor.

Just guessing here. Keep your fingers crossed!

mikey1

thanks,

its strange, i was getting the code every other day for over a month, and ever since i posted this thread the light has not returned since, over two weeks i believe,