I got P0420/ P0430 error code today. I know if means Catlyst System Efficiency Below Threshold (Bank 1/ Bank 2), but what does that mean? I have a set of Kooks and a 93 Tune. Since I'm unsure of the code, I wasn't sure if I should clear it or not?

Thanks for the insight.

 

I believe the rear O2's are reading that the cats are not working. From hat I have seen, bith Kooks and ARH cats flow so well that they often trip a CEL, especially on 07+ stangs.

 

That's really another way of saying "both Kooks and ARH cats aren't really doing the job". It's definitely not that they are "flowing well", but that they are no processing the exhaust gas well.

Oh well. I guess a bit of clean up is better than nothing at all.

 

Thanks guys. I just cleared the codes. I'm not due for a inspection until January 2010, so I'll be good until that point. I'll bring it back to my tuner to make adjustments right before that time.