Recently had a full decat fitted, along with a number of other parts, and I am now experienceing the P0420 Catalyst System Efficiency Below Threshold CEL.
I know that this is no biggie, but am now confused if this is fixed by the 2.2k ohm resistor, or if I need to invest in the MRT etc CEL fix products?
Car is an MY02 btw. Any diagrams/pics/links on where the resistor goes would be helpful!

 

The resistor you refer to is for the EGT (Exhaust Gas Temp) warning when you have a decat up-pipe in place.As it sounds like you have a decat downpipe (Which is why you're getting the 0420 error) what you need is indeed the fix by MRT (I have the same fix on my 01 WRX and it works a treat!!)

Good luck

Nick

 

Best I cancel the order for the resistors then!
I have an order for other bits in with JW Racing, I'd best add the fix to that then.

Thanks

 

just to say i had that cel code the other day on a standard legacy

thats all i had, just felt i had to tell you!!!!!!

 

I have made this mod two month ago and no more P0420 code:
Parts required:

1 x 1M ohm 1/4W 5% Carbon Film Resistor
1 x 1.0µF 35V 20% Dipped Tantalum Capacitor


Hopefully. this diagram will help you! (see link above)

http://forums.nasioc.com/forums/showthread.php?s=&threadid=218637
Cheers