hello, I've recently put a PPP STI DP on my WRX 01 with fullH&S exhuast after that and the centre cat removed. But i've had the check engine light iluminate twice once before the DP was fitted and once since. The car passeds its MOT last week. I've got a psi3 data monitor in the car so i know the fault is 0420 cat below threshold.....
I just cleared the fault code and all is good. Its only happened when coolish or when being used in commute mode (sllowww).
Any help would be greatful.
Many thanks
Peter

 

Peter

I was plagued with P0420 (cat below threshold) problems with my Haywood and Scott De-cat MY02 WRX

Like yourself I have a SECS to make sure the CEL code is not terminal I tried a CEL fix but AFAIK the later bugeye has a better ECU which looks for fluctuions in the readings from the missing CAT and lights up anyway

MY01 ECU might fare better with a CEL fix or a "resistor" in the right place

P0420 CEL problem was comprehensively solved by the EcuTeK remap which mapped out the annoying CEL ........... and a lot more

Midlife.....