[mglax13]

Hello everyone,

I recently purchased a used 2008 E92 335i. This was a second owner, who unfortunately couldn't give me many details about the mods done to the car, other than just tell me that it has down pipes. I looked and confirmed that there are not OEM down pipes in the car.

I mention this because I keep getting an error light on the dash. I check the code and it's P0131 - Oxygen O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1).

Now I don't know what kind of down pipe are on there or what was done in the install, but I'm assuming that I'm getting this code because of something to do with the down pipes.

Is this just a matter of a bad O2 sensor that just needs to be replaced, or is this something that needs the DP fix?

I've searched a lot all over this forum for the last few hours (I may be new in this forum, but I've been on forums for the last 10 years, I know repetitive questions are annoying), but unfortunately, I can't find anything really conclusive that can help me out.

Thanks in advance for any help you can give me.

[mglax13]

Bump? Anyone? I feel like someone needs to know something about this. I reset the code and it reappears after a few days. Car feels like it's running the same when it's on or not.

[Ingeniator]

Sensor 2's are the after cat sensor. You want to check the wiring and if that is good replace the precat O2(Sensor 1).

[mglax13]

Thanks for the advice!