can someone tell me what ecu code 67 (P0420 Catalyst System Efficiency Below Threshold) means? i just got the car and its throwin this code. The car also cam with an aftermarket exhaust. could that be the problem? thanks.

 

the aftermarket exhaust shouldnt have anything to do with your code. maybe your cat is bad or maybe they hollowed it out before they put the exhaust on.

 

your cats gone...you can try feelin you exhaust for good flow...or if you have access to a lift...try hitting the cat(car off), if it rattles, its for sure bad. tip: cats dont go out by itself...the prob is usually upstream like towards the motor...maybe o2 sensor...injector

 

anyone else experience this code?

 

yeah, but I dont know why I am throwing it. I have a pretty new high flow cat.