Two catalytic converters?

Recently I've been told by a few people that my car has 2 cats, but my Chilton book doesn't say anything about a second cat.
Is it possible that the secondary cat might be causing my p420 code? (p420, catalytic converter below efficiency threshold for bank one.)


I think it doesn't have a second cat, cause if it did there would probably be a third sensor to make sure it's functioning properly, am I right?

Hi everyone;

I would like to know some suppliers in China mainly in exhaust system.

They could Chinese or even Joint Venture in China.

I could have some like JV bosch, Faurecia

Thank you in advance for your help

My 04 Malibu has 2 cats, one left bank and one right bank. They both bolt right on the exhaust manifold.

that makes sense that dual exhaust would have 2 cats, but mine is an 01 with single exhaust. When I looked today I saw a device behind the cat that kinda looks like a smaller second cat, but I think it's the resonator. Anybody know for sure what it is?

Hi everyone;

I would like to know some suppliers in China mainly in exhaust system.

They could Chinese or even Joint Venture in China.

I could have some like JV bosch, Faurecia

Thank you in advance for your help
You need to make a new thread here, this one has nothing to do with this issue, plus you are very unclear here. Re -read your post.

Ive got a 97 mali and i was guna hack off that second one thats a lil smaller but there are 2 sensors on ither side of it and it is a resonator not another cat. Ive went everywere to get opinions on it and most people said it doesnt really need to be there, it more or less quiets it down that much more....

that makes sense that dual exhaust would have 2 cats, but mine is an 01 with single exhaust. When I looked today I saw a device behind the cat that kinda looks like a smaller second cat, but I think it's the resonator. Anybody know for sure what it is?

Mine is single exhaust, the 2 banks end up into one pipe. Pop the hood and look and see if you have 2 cats, one on each manifold.