which Oxygen Sensor?

[Pug]

Getting this error from my 3:
P0138 - O2 Circuit High Voltage (Bank 1, Sensor 2)

Do you know which sensor (Bank 1, Sensor 2) it is referring to?
Front, Centre or rear?

Thanks

[Donutz]

Sensor 2 is the rear sensor. Our Canadian (non-Cali) version of the mazda 3 only have 2; I believe it is the Cali emissions standard specific cars that have 3 sensors (I.e., have a centre sensor).

I bought mine from Rockauto online for $92 cdn shipped to my door. It's a Denso direct fit with 31 inch cable. I don't know how long of a cable you'll need; I had to get a longer one because I have the sensor relocation kit installed. That said, you can get them cheaper than this, whether Denso or another brand. I recommend getting a direct fit sensor though.

[Pug]

Jason,

Great info, do you know where exact the sensor is located? I can't seem to find it by looking up from the back.

Also, I checked Rockauto online but I can't seem to find a Denso O2 cable for cheaper than $112. What part number did you use?

Thanks!


Sensor 2 is the rear sensor. Our Canadian (non-Cali) version of the mazda 3 only have 2; I believe it is the Cali emissions standard specific cars that have 3 sensors (I.e., have a centre sensor).

I bought mine from Rockauto online for $92 cdn shipped to my door. It's a Denso direct fit with 31 inch cable. I don't know how long of a cable you'll need; I had to get a longer one because I have the sensor relocation kit installed. That said, you can get them cheaper than this, whether Denso or another brand. I recommend getting a direct fit sensor though.

[Donutz]

I believe the OEM location is in the header. One should be before the cat, and the other should be after. When I have a sec I'll run out to the garage and snap you a pic.

The part number is 2344390 (there are some dashes in there somewhere). I guess I should clarify that I have a 2005 2.3L sport model. On this page, it is the first Denso o2 sensor listed: clicky (https://www.rockauto.com/catalog/x,carcode,1433045,parttype,5132,a,www.google.ca%2B Search%2Bfor%2BEmission%2BOxygen%2BSensor%2BDENSO)

[Pug]

I have a 06 but RockAuto shows a different part# 2344392, cost is $121.79.
Don't know what gives since they should be the same?

I guess I have to do some research to see what is the difference.

Thanks!

[Pug]

found it, the connector looks a bit different and it's shielded. Not sure if it's worth the extra $50.

234-4390 http://www.densoaftermarket.com/catalog/product_image.php?id=234-4390&part=o2sn

243-4392 http://www.densoaftermarket.com/catalog/product_image.php?id=234-4392&part=o2sn

[Donutz]

Yeah bro, that's weird. I don't know why there is such a huge difference in the price between 2005 and 2006. There is a Bosch universal for under $60 though.

On this site there appears to be a direct fit bosch (looking at the pic) for $56.95 US. Also, there is a Walker for $67+ clicky (http://cpwstore.carpartswholesale.com/catalog/?PN=9167&N=0&VN=4294967177+4294966839+4294965387+4294966832+429 4966817&Nr=AND(universal:0)&sv=0)

[Pug]

I just realized Mazda has a 128,000km or 8yr emissions warranty, since my ride is stock so I'll check with the dealer first. Once again, thanks for looking up the Part# for me.

[prettyteen]

my check engine light comes on and i had it checked mechanic said error P0138. where can i purchased this oxygen sensor and where can i have it fixed i need a good mechanic. please help

[Donutz]

http://www.torontomazda3.ca/forum/showthread.php?53023-Why-search

[Zuluwun]

^lol.

If you need a mechanic, try searching through shop/service reviews. Shouldn't be too difficult (ie. first thread!)

[ginnai]

I just replaced two of mine (49K miles). The entire job took about 1 hour and 1 tool (a oxygen sensor socket, $15-30). My 2006 has three. Two are accessible from the hood and one from underneath. Mine were from autopartswarehouse.com... each was a different price, averaging about $120. It is simply a matter of screwing out the old sensor and screwing in the new. A shop will charge you at least an hour's work for each and mark up the part itself... but if you only need one, you could be done in 15 minutes. Message me if you need any advice.

[ginnai]

Sensor two is in the back of the hood (center). Its a bit of a reach, but not too bad.