On my way to work this morning and my cel came on. stopped at the mitsu dealer to pick up an oil filter that I needed this weekend anyway. he read the codes and came up with a cat failure. he cleared the codes and off I went. I have a helix dp, helix high flow cat and rnr catback. I have had these installed for well over 1500 miles and the light just now went on. I just finished installing a mini battery and nwe i/c piping. I thought that the helix cat was not supposed to throw a cel or would something else have to do with it?
code was 0420-catalyst below efficiency
thoughts?

 

your a/f ratio maybe the contributing fact.

that or sometime it craps out. that or your o2 sensor went bizark.

 

put 2 anti foul spark plug spacers on th 02 sensor itll go away

 

My Helix HF cat w/ Xede & custom tune throws a CEL every other day....
Tried the spark plug anti-fouler, there was no way for two of em to fit like the how-to says. Tried with just one and it was hitting the underside of the car
Took it out and going to an o2 sim patched into my Xede.

 

how did you clear the code?
is there a way to do it without a code tool or the dealer?

 

disconnect the battery
and then do this = https://www.evolutionm.net/forums/sh...d.php?t=114931

 

is the code p0456?