I keep throwing a 0420 code
Catalitic converter below threshold

OK I have a ton of mods including a header (with mini mania cat)
I contacted MINI MANIA ...
ended up buying a reset tool
no big deal ... I know what is happening but dont want to miss a code
I once saw a "plug in" that woudld by-pass the cat sensor...
thinking this would be a good idea...

Any input or help ???

 

after about a year with Miltek Header/Cat i also got p0420 codes that kept returning. Miltek had me try spacers in 02 sensor, made a special plug but code kept returning. Finally sent new header which has worked for last 4-5 months w/o issues. I'm told many of aftermarket cats fail after a year especially with track time. check out search there are threads on this