Hi,

My stock cat failed a few weeks ago (p0420) so instead of replacing it with stock I got the RP High flow cat. I got that installed about 2 weeks ago and this morning I started my car and the CEL came on with P0037.

I researched this and it sounds like it is the rear o2 sensor? Any advice on this? Could this have been the problem all along or are the codes unrelated?

Thanks

 

Re-set the ECU

 

I cleared the code with an OBD2 reader and it came back after 2nd start. Clearing the ECU different?

 

is the rear O2 sensor hooked up properly? wires on it are undamaged?
You "shouldn't" have a CEL from the supercat. What did your stock Cat look like when you took it off?

 

https://www.rx8club.com/series-i-tech-garage-22/new-code-after-mid-pipe-installed-fix-171292/

Sensor could have been broken during install.

 

We were very careful taking it off. I doubt that we damaged it. I guess it could just be a coincidence.

 

Make sure the exhaust doesn't have a leak.
No leaks, then for the fun of it clean the MAF, re-set ECU and see what happens.

 

those sensors are fairly sensitive so "damaging" it doesnt require too much

kevin.