I got the same CEL code. I thought it was the actual stock Manifold CAT that went bad...I think its just the 02 sensor...I switched out the Header for another one and the CEL disappeared...I dunno I could be completely wrong and maybe it is the whole whole Header that went bad too.....I am still roll'in w/ a CEL on all the time.

Just too bad that the DEZOD Green Header is not CARB Legal for CA people.

 

for those who think a cat cant go bad at 80k miles it is very possible
here is what mine looked like when i removed it... completely clogged up

 

http://oi49.tinypic.com/28tdg9.jpg

 

I am a complete newbie when it comes to cars. I have the same CEL code: p0420 Catalyst Efficiency Below Threshold (Bank 1). The thing is, All OBDII sensors read as "ready". wouldn't the Catlyst or O2 sensors read a "not ready"? Or any of the others for that matter.

 

Not sure. Im a newbie too lol. If u cant find the answer i suggest starting a new thread about ur problem

 

I would suggest just looking for a leak first. The o2 sensors are reading to much or too little oxygen but the code is saying it is the cat. You could have a leak and only need a gasket somewhere. I would search around for that first. Have you removed your o2 senser from the primary (header) cat? Is it all gummed, tarnished, hazy? It could also be one of these. Do not automatically think it is the cat even though it could be. How is your gas mileage? Is it below average for a tC?

 

It was the cat. It was all fried up

 

My catalytic converter went bad & causing my to burn gas like crazy!! I went to the shop to get it replaced & they quoted my a min of $500. If I buy the part myself, is it something I could replace myself? Please help because I'm tired of going to the gas station every other day!!

 

It should be easy to replace ur self.. U will need some jack stands. I would recomend buying a used OEM cat on ebay with low miles on it.. I got mine for a little over $100... If u dont trust urself with the fix, find a backyard mechanic that can do it for cheap. I got mine replaced for $65 by a trusted backyard mechanic

 

A bad converter shouldn't make you burn extra gas, as air and fuel adjustments are made using the O2 sensor in the manifold, before the converter. The opposite is true however, in that running excessively rich can cause your converter to go bad. If excessive fuel is the issue, figure out what's causing that and get it fixed. It might be a bad primary oxygen sensor, but a OBD2 trouble code should clue you in.

 

Hello, I have a 2013 Scion Tc and it was stalling to start and the check engine light came on. Took it to a mechanic and he says, it's the catalytic converter, he wants to charge $700 for it. My car just has about 47k miles, could this be it? Before that, another shop said, it was the sensor but he wasn't sure.

Chicago IL