wcooksey

Here's another CEL question, but this one has got a little twist.

Got a CEL, took it to the shop, they did "full" diagnostic and returned the code for Catalytic Converter. I don't remember the code exactly, but I looked it up when I was at home, and sure enough it was Catalytic Converter.

Ok, so I need a new Cat and will probably just buy one at autozone for $150 or so, and bolt it in.

But here's my actual question: How is the system getting "Catalytic Converter"? I looked in helms, and no sensor screwed into the Cat. Doesn't seem that the o2 sensors would be able to "sense" this. Would sensors on the manifold trigger Cat code due to higher back pressures? Someone help me understand. I replace parts and such, but I’m not a mechanic, so I’m still figuring out the principles behind how the stuff works.

Thanks,

William
98 Civic EX

stereo

haveing the code would help ...on 96+ cars they have 2 O2 sensor one on the down pipe and one on the cat. the PCM monitors the 2 sensors if the cat. isin't doing a good job the reading will be higher and throw the CE if I had to guess you got the P0420 code.

wcooksey

Yes, just verified. It was PL0420-Cat converter. So it would be the front and rear O2 Sensors in combo that generate this code? OK. Well, that sounds reasonable.
Thanks,