Is this the same code everyone gets intermittently when they have a aftermarket cat? CEL came on last night. 1st time. Code is P0420. Catalyst system efficiency below threshold. Or is it o2 related?
I cleared it & hasn't come back. Been running the RT cat for a year now no problems.

 

i get it all the time....goes on for a few weeks then off. happened after i did my catback. I have a defouler ready to put on to keep the code off.

 

I put a defouler on when I installed mine and no issues so far.

 

I only get codes on long highway drives 3 hrs plus.
But it's no big deal, pull fuse,and it's back to new.atleast till I do long drives again.
If it pops back on really soon I would look further into the code though.

 

I have had RT cat on my car since my OEM cat broke.
I usually get engine light(PO 420) when I drive steady speed.
I'm gonna get defouler soon. and I noticed little bit of ricy sound after I installed RT cat. I didn't like it first time. now I got used to it.

 

I just had to deal with this so I could get an inspection... Basically you jus need to get a defouler, a 90 degree one works best because of limited space... Basically the ecu is reading the increased flow from the high flow cat as the stock cat going bad causing it to throw a false code.. I finally put the defouler on and have been code free for 300+ miles

 

i've had my rt cat on for 3+ years and have yet to get a cel.

 

Hasn't come back, so IDK.

 

I had that intermittently as well. I picked up a defouler, it went away, then the defouler broke (long story) so now I run without it. No CEL in 2-3k miles