Code p0135 will not go away even after replacing o2 sensor with brand new oem
 

I bought my 05’ ap2 a few months ago. It has an invidia q300 and test pipe. I knew the o2 sensor code was there because the guy I bought it from talked about it, he said it was just because of the test pipe.

turns out code p0135 is the the primary o2 sensor (before the cat). I replaced the sensor with a brand new oem one. I tried resetting the code and it came back. I’ve tried everything at this point and this light just won’t go away.

im not in limp mode or anything, car drives fine, running a little rich maybe but that’s it. I just want this cel gone :( please help!

Is it the correct Honda sensor for your car

yes. My friend plugged in his scanner and it’s showing the sensor isn’t even getting power, as if there’s no sensor even plugged in. I was looking on some other posts and some people are saying the only way to fix this is to get a new ECU. It not THAT expensive but I really would like to not do that.

P0135 has nothing to do with the test pipe.
P0420 is the code for inefficient cat

The ECU connections for the primary and secondary o2 sensors can be accidentally plugged into each other, shorting out the ECU. This could be what happened.

Hey Jason , did you end up finding the solution to this ?