Hello

I'm having issues with my 05 Pathfinder with about 128k miles

I'm currently getting these codes

P1278- air/fuel ratio sensor

P1288- please refer to vehicle service manual!

P1289- please refer to vehicle service manual!



I've tried looking online for the P1288- P1289 codes but no luck

i'm also having transmission issues with it slipping with taking off i think the torque converter might be going out...I've already place my transmission 3 years ago.

please help find the problem with my path...and more info on my OBD2 codes.

any feedback would be appreciated.

thanks,

can you clear the codes? If so, do they come back right away?

The F/A sensors are the primary O2 sensors on the upstream side of the catalytic converter. I've changed mine, it wasn't too bad of a job. Cost about $200 for the sensors though. Use NGK Sensors.

As for the transmission, have you checked the fluid quality? what color is it? Transmission slipping can be an indication of the infamous radiator cooler failure, many posts on the forum about that.

t

disallow wrote:can you clear the codes? If so, do they come back right away?

The F/A sensors are the primary O2 sensors on the upstream side of the catalytic converter. I've changed mine, it wasn't too bad of a job. Cost about $200 for the sensors though. Use NGK Sensors.

As for the transmission, have you checked the fluid quality? what color is it? Transmission slipping can be an indication of the infamous radiator cooler failure, many posts on the forum about that.

t

i've erased the codes but they come back every 4th day. sometimes i got all the codes i posted and there are times i get one or two codes

mainly p1288 and p1289

P1288-Air/fuel sensor 1, Bank 2, slow response
P1289-Air/fuel sensor 1, Bank 2, slow response
P1278-Air/fuel sensor 1, Bank 1, slow response

It could be that both front sensors are faulty...but they could also be caused by a faulty MAS, intake leaks, leaking PCV system, incorrect fuel pressure, exhaust leaks, or shorted/open air/fuel sensor harness or connectors.

Are these sensors the Oxygen sensors?

smj999smj wrote:P1288-Air/fuel sensor 1, Bank 2, slow response
P1289-Air/fuel sensor 1, Bank 2, slow response
P1278-Air/fuel sensor 1, Bank 1, slow response

I replace the Cam sensor's about 8 months ago...can this be a problem?

http://www.thenissanpath.com/viewtopic. ... 3019#63019

smj999smj wrote: It could be that both front sensors are faulty...but they could also be caused by a faulty MAS, intake leaks, leaking PCV system, incorrect fuel pressure, exhaust leaks, or shorted/open air/fuel sensor harness or connectors.

I forgot to mention that there are times i get P430 on the path.

can the Path have air leaks on the intake like this Armada?
http://youtu.be/wyijdN61acI


i just cleared all the codes earlier today...I'll post whatever i get in a few days

Air/fuel ratio sensors look like oxygen sensors and perform the same function. They are more precise and work at a much more limited voltage range than oxygen sensors. When looking them up at part sites, look up "oxygen sensors." I prefer NTK sensors, which are the OEM supplier to Nissan, and get them from Rockauto.com, where they are much cheaper than getting the genuine Nissan part. You can look up the part numbers at www.ngksparkplugs.com. Cam sensors should not cause oxygen sensor codes. A faulty oxygen sensor can cause a P0420/P0430 code to set on it's respective bank.
I'm not aware of intake leaks being a common problem on the R51's with the VQ40DE engine, but it's possible. I have heard of a couple of problems with the PCV valve and/or hose, so you may want to check there first.

smj999smj wrote:Air/fuel ratio sensors look like oxygen sensors and perform the same function. They are more precise and work at a much more limited voltage range than oxygen sensors. When looking them up at part sites, look up "oxygen sensors." I prefer NTK sensors, which are the OEM supplier to Nissan, and get them from Rockauto.com, where they are much cheaper than getting the genuine Nissan part. You can look up the part numbers at www.ngksparkplugs.com. Cam sensors should not cause oxygen sensor codes. A faulty oxygen sensor can cause a P0420/P0430 code to set on it's respective bank.
I'm not aware of intake leaks being a common problem on the R51's with the VQ40DE engine, but it's possible. I have heard of a couple of problems with the PCV valve and/or hose, so you may want to check there first.

I know where the oxygen sensors are located but where are the AIR/FUEL RATIO SENSORS located in the pathfinder?


basically my OBD2 codes are Air/fuel ratio and not oxygen sensor?


My OBD2 reader does let me see the data stream but i'm not sure what readings i should be looking for.

I appreciate all the feed back...

I found these diagrams for 05-12 Frontier. I'm not sure if its the exact same setup as the Pathfinder.


2005-2012 Nissan Frontier Air/Fuel Ratio and O2 Sensor Location

The front O2 sensors ARE the Air/fuel ratio sensors. Diagrams above are correct for Pathfinder as well. Remove the wheels and pull back the plastic wheel housing and you'll see them. If you change them, it's best to do with the engine cold unless you like burns on your arm.

smj999smj wrote:The front O2 sensors ARE the Air/fuel ratio sensors. Diagrams above are correct for Pathfinder as well. Remove the wheels and pull back the plastic wheel housing and you'll see them. If you change them, it's best to do with the engine cold unless you like burns on your arm.

Are the sensors I need the precat?

SES codes in RED






P1288-Air/fuel sensor 1, Bank 2, slow response
Part no 24320
(driver front 02 sensor) before cat

P1289-Air/fuel sensor 1, Bank 2, slow response
Part no 24320
(driver front 02 sensor) before cat

P1278-Air/fuel sensor 1, Bank 1, slow response
Part no 24320
(passenger front 02 sensor) before cat

Sensor 1 is the front sensor, which is "pre-cat." Bank 1 is the right bank, or passenger side. Bank 2 is the left bank, or driver's side.

My check engine light came back on and and I got the same codes with a different OBD2 reader that I have.

I got four codes both they are both duplicates obd2 codes.

ONE



TWO



THREE



FOUR

Did you replace the B2S1 sensor? If you did and the codes came back, erase the self-learning memory and the codes and see if they return. If they still return, you'll need to check the harness and connectors for the B2S1 sensor circuit.

smj999smj wrote:Did you replace the B2S1 sensor? If you did and the codes came back, erase the self-learning memory and the codes and see if they return. If they still return, you'll need to check the harness and connectors for the B2S1 sensor circuit.

i haven't replaced the sensors yet but i will soon. I just wanted to make sure if the codes i gOT were the same ones i got last time...


the codes were cleared and will do clear them again just to make sure

once I do the repairs I'll update this post