Replaced 02 sensor, Code still coming up

[spudfinder]

Hows it going TNP. I have a 98 Nissan Pathfinder v6 with 4wd and ive been getting a code for the 2 o2 sesors before the cat. I replaced them with brand new Bosch sensors and the code came up again for the left side 02 sensor. Thinking it might of been a faulty o2 senor, i replaced it with yet another brand new Bosch sensor. Now im still getting the code for that sensor.

Id prefer not to take it to a shop and pay out the ass. I can replace and repair almost anything i just dont know where to start.

Cliff Notes:

Code for left bank pre cat 02 sensor
Replaced 02 sensor twice with brand new ones
Code Still coming up


Please help. I need to get the car inspected in 2 days and cant figure out what is causing this light to stay on

[blink32]

Get the service manual. You'll find the links in the VERY FIRST (and only) sticky in the R50 forum. In there you will find detailed troubleshooting steps. Many times, while the error code seems very direct, there can be more than one thing that can cause it. The troubleshooting matrix will help you find out for sure what is going on.

Shooting from the hip though, what is the actual code you are getting? I see from the manual that you only have 2 O2 sensors, one on each side. I also saw a note about not over-torquing the sensors, and if you do it will set the MIL off. So are you cranking down the sensors? It is also possible to get multiple bad brand new parts. To rule out all things why not swap sides. Move the known good sensor from the right side to the left. If the error stays now you have a wiring or ecm issue. If the error follows the suspected bad O2 sensor then you know you have another bad sensor.

I take it you are clearing the MIL each time and then it's coming back on?

[spudfinder]

There is 4 on the car. 2 pre cat and 2 post cat. I am getting codes P0131 and P0141 or P0151. I had cleared out the MIL using the scanner and then after about 60 miles it came back on. Im tightening them down tight but not struggling to tighten them.

[blink32]

So here's what I'm seeing:

P0131 : Right Bank Front O2
P0141 : Right Bank Rear O2
P0151 : Left Bank Front O2

I assume these are the 3 you started with but now you are down to only P0151? Go to that sticky I mentioned, and get the Engine Control System (EC) manual and get to page 169. There are a few procedure on what to test for to see if the sensors are good and it has you test other sub-components.

[bbermann]

So here's what I'm seeing:

P0131 : Right Bank Front O2
P0141 : Right Bank Rear O2
P0151 : Left Bank Front O2

I assume these are the 3 you started with but now you are down to only P0151? Go to that sticky I mentioned, and get the Engine Control System (EC) manual and get to page 169. There are a few procedure on what to test for to see if the sensors are good and it has you test other sub-components.

Blink32 thank you, big time.

This thread saved me a few bucks. I did a search on O2 and came up with this thread.

My Pathfinder would intermittently shudder and die while idling. I also got a suplher smell and thought it was a cat going bad. I plugged in the code reader and got a pending error code of P0131; O2 sensor 1 bank 1.

I followed your suggestion and page 169 of the maintenange manual said to loosen and retighten the three grounding screws. Everything looked solid but I thought OK, easier and cheaper than getting someone to replace the O2 sensor.

THis actually fixed the problem. Saweet!