Reverb2005

Hello,

I have a 2005 Civic Reverb (annoyingly enough, hard to determine parts sometimes), which I guess communicates well to a DX I guess?

Anyway, I have had the code "P0139" pretty much up on my dash for a couple years now. I have never noticed any terrible milleage as I drive about 210 km everyday to work, filling up about every 3 trips, so that's like 630 km and from my esimation, I use about 42L of gas on that, so (42/630)*100 = 6.66L/100 kM or for you Americans, that's about 35.32 MPG. I know the highway specs are technically a bit better than that, but come on, it's a 9 year old car now.

I know there are threads about this code AND the oxygen sensor and I HAVE READ EVRY ONE OF THEM, just so that's clear as well, I have already done a bunch of research. What I am actually asking is which darn Denso sensor do I actually need? From what I understand, the 2004 and 2005 models use a wideband O2 sensor (we are talking about the oxygen sensor AFTER the CAT here) so the price has shot up dramatically from the 2000 to 2003 models. Now, when I visit the Majestic Honda site to find my part, I would look under "EXHAUST PIPE - MUFFLER" and find a diagram that does not match what my exhaust system actually looks like.



Now, oddly enough, I look up the "EXHAUST MANIFOLD (SOHC VTEC LEAN)" component and volia, there is my manifold and CAT, DIRECTLY AFTER THE MANIFOLD, not under the car as the first diagram appears to show, why is that exactly?



So from all this, I am looking for part number 36532-PMM-A01. Fine. It's like $275 here in Canada.

Now, I am wondering why it is that when I visit other sites I get a complete mixture of differing prices from about $60 to this price of $275? I know the part is not a "Honda" part, but clearly a Denso sensor. Ok, that's fine too, say I don't want to buy it from the dealership, Desno says the sensor I need is a "234-4092" which has the OE plug on it so I can plug it right into the existing connection without splicing.

On autopartsway.ca (a good auto parts store in Canada) the sensor is only 60 bucks?
http://www.autopartsway.ca/PartDetails.cfm?234-4092/D45

OR, if I select my actual vehicle, I get this part:

http://www.autopartsway.ca/PartDetai.../pagenum1/tabS

So with all these choices I am throughly confisyed as to what part I actually need and whether I need to spend $60 or $275 on the correct part. Any input on the general area would be appreciated!

Thanks.

ezone

I would use an online Honda dealer parts catalog, enter your VIN so the catalog can eliminate unnecessary options. (You should be able to get the correct parts pictures this way too.)
Obtain original Honda part number, then use the cross reference guide to convert to the DENSO or NTK part number. If possible.

You are in Canada?
torontohondaparts.com/

I'm in the US, your linked parts house site did not like me.



The rear sensor (after the cat) is a regular oxygen sensor, not an AF sensor.



You could check out the original sensor on your car now, see what brand it is.
It should be either DENSO or NTK.
Go to the website for that brand, locate the correct sensor part number this way.

Then try to locate the same part number sensor on your local parts house website.

HTH

Reverb2005

For anyone in the future reading this, I would definatly advise you to do some shopping when you find the actual sensor you need as parices vary wildly from site to site for seemingly no reason. Turns out the sensor I need IS a Denso, model number 234-4092, right from the Denso website.

After checking with my local parts store, they wanted $120 for the sensor. Well, after some shopping, I found it on amazon for $33.42!! Exact same sensor, OE design, just missing the rubber grommets on the cord, so I'll have to secure them another way, but still, unbelieveable. Here is the link:

Reverb2005

So, Unfortunately, I need to bring this thread back to life.

So I changed the rear O2 sensor with the sensor I posted back in August and reset the ECU (Fuse #6 for 10-15 seconds) and the code was gone. The check engine light stayed off for about a week or two and then turned back on with the same code, P0139.

I have checked all the wiring to the sensor and to the computer and it is all securely fitted and seated properly. The only other possible cause that would seem to trip this code is an exhaust leak, according to multiple sources and websites.

I called my honda dealership and they suggested I go to a different shop (They just don't have a welder on site) and see if they can weld the manifold in the case of an exhaust leak. I would go the welding route before the manifold swap since the manifold is connected directly to the cat. Now, what I am wondering is what are the chances of the exhaust leak actually being the culprit here? Shouldn't I hear/see an obvious exhaust leak? I do hear a little bit of "farting" going on when I accelerate and most definately when I gear-down at higher speeds (to listen for the leak) so there may in fact be a leak somewhere on the manifold. The problem I am having is I do not see any cracks in the manifold, though I have not taken off the heat shield since the bolts holding it on are on there pretty damn good. I took a manuvreable mirror and looked all around the manifold.... couldn't see the crack anywhere! Could the crack be in the gasket?

Any general info here would be very helpful! Thanks!

ezone

I found a link in another thread about a software update for this code. Contact your local dealership

Bulletin copy, PDF: www.civicforums.com/forums/attachment.php?attachmentid=77239&d=1252107997

Reverb2005

Hey ezone, thanks, I totally missed that thread.

I contacted the dealership and they are going to perform the upgrade for a small fee. Crossing my fingers! I'll post an update after the upgrade.