Having a little O2 sensor problem.

[Griever423]

Hi all, I have a 2001 Nissan Sentra SE with PP. I'll go ahead and get right to it: I have an O2 sensor problem.

Long story short my rear O2 sensor went bad, causing me to throw a code: P0141O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

Now, I've finally broken down and bought a new O2 sensor. I installed it, and the code didnt go away. No problem I thought, so I reset my ECU, which didnt help. I then took my car to a buddy's shop, and had him use the computer to clear the code. It worked great, for about 20 miles, and then it wa on again.

I'm kinda stumped here. Is the 02 sensor I bought just bad? Or do I have another problem unknown to the computer? If anyone has any insight please let me know.

Edit: Oh, I forgot to mention, I have aftermarket headers.

[nametakennow]

Is your second sensor relocated behind the cat-converter?

If not, it's registering as bad because the a/f ratio at the first is the same as the one at the second, so the computer (rightly) thinks your precat is gone and/or malfunctioning. By relocating it you trick it into thinking that you still have the precat. Some people just use a resistor setup to fake a good reading.

Alternately, if you're using a generic Bosch sensor your Nissan wiring may have fried it. Nissan uses a slightly different power level in its sensors. I had a shop gunk all of this up on my car resulting in the removal of my turbo setup and multiple thousands of dollars of repair bills in trying to find a very simple problem.

[Griever423]

Well, the spot for the O2 sensor in the stock down pipe was precat as well, so I don't get why this one would read differently. Where would you suggest locating it?

It's an OE type Bosch O2 sensor, it looks identical to the stock one.

If you could elaborate about this resistor trick that would be great. I've seen a few threads on it on b15sentra but never really saw what it was they were talking about.