I have an 04 it’s only got one catalytic converter so not sure if yours does have two. I would verify it has two then replace the oxygen sensor and maybe check to see if the catalytic converter is good for that area.

 

OP believe your right.
How many miles?

 

It has 230k miles

 

P0420 would be the efficiency error code for the front manifold cat.

 

I checked the exhaust pressure, to see if one or both of the cats is clogged, but the pressure was low.

I put one of those O2 sensor spacers on the second O2 sensor, but the code returned.

I added a spacer to the third O2 sensor, and the code has not returned, and allowed me to pass the smog test.

I think my second Cat is bad.

I live in CA, though, and we have to use CARB certified cats, so they are expensive.

I may just sit tight for a while, unless anyone has a suggestion for an inexpensive cat replacement?

Thanks,

sabbates

 

Considering the year/mileage i vote for " leaving well enough alone."

 

Is your car a California car? If it is it will have 3 oxygen sensors if it's a 4 cylinder. One on the manifold by the head, one right after the flange where it bolts to manifold. And one right after the resonator before the flange going to the muffler

 

Is your car a California car? If it is it will have 3 oxygen sensors if it's a 4 cylinder.

Yes, California car. The spacers are on the second and third O2 sensors.

 

Hi same problem I got 2006 145k. camry 4 cyl. Code 2423 spacer on last down stream 02. Worked for a while check engine light on then comes off after driven 50 so miles. Yup. California cat. Is bank$$$. Just wanted to know what you have done or any body knows what to do. I know eventually the cat or cats will crap out and run bogging out lack power. Majorly. Cats run 1500 to 1900 $