po420 code- 2004 Silverado 4.3

[John Coody]

looking for suggestions on checking out cat. convertor. was told maybe temp. sensor could be bad. don't know how to test. any help would be helpful. Thanks!!

[CamGTP]

There really isn't a way to check the cat out unless you remove the exhaust just to make sure the cat converter is still all there. But even that doesn't tell you the whole story, it could still be broken down inside and not doing it's job good enough. Thus the check engine light for a inefficiency code.

 

The temp sensor won't have anything to do with it.

 

The only test you really have is swapping the two rear o2 sensors side to side. If you swap the sensors and the code turns into a P0430 for bank 2, then it would be a bad sensor but usually it's the cat itself that is bad if you get that code still for P0420.

 

Buying a new cat should fix the problem or you could try spacing the sensor out of the exhaust a little to stop tripping the code.

[dna9656]

Any muffler shop will inspect that cat for you, if you need cat(s) get the corvette rated ones, they have a high flow rate so your exhaust is less restrictive. I agree with CAMGTP too.

[John Coody]

I will try swapping them and see what code i get. I thought of spacing the o2 out, It doesn't look to hard to do.

thanks, both of yall for the help!!