Anyone else getting this cel (P0420) ? "My catalyst efficiency is below threshold". I'm running Vishnu Stage 1 +. Is this my exhaust? How can I fix? Thanks

 

That sounds like an exhaust deal, don't quote me on it though.

 

it is just like on the subys. buy the perrin cel fix. I got the one for my suby from www.rallysportdirect.com I know perrin makes it for the evo. give him a call i bet he can get it.

 

What that code means is that the post cat o2 sensor is reading very similar to your pre cat o2 sensor,thus your computer thinks that your cat is dead,or just not firing off.Could be caused by a number of conditions,although the most likely cause is not having a cat at all.The perrin thing will work well as it tricks the computer into seeing what a good reading would be from your post cat o2 sensor,without it even having a cat.

 

Thanks guys, I appreciate the info. What's weird is that I do have a cat. It's high flow but I didn't think that would cause the code to pop. Any other possibilities ??? Also, when you say that Perrin can "fix" the problem, that just means they can sell me a "less sensitive" sensor. Right?

 

Not less sensitive. what it does is make the sensorread inbetween the values that are in the ECU. The high flow cat might do it. It most likely doesn't clean the exhaust as much causing the senor to think that it isn't working right. The only way to fix it is to put on a better cator the stock cat. Or put on the CEL fix. The cel fix is a some resistors and capacitors that get wired into the sensor line. Actually i think the perrin one is juat a plug in so you don't need to solder it If it was my car i would get the cel fix.
from perrins site