My SES light came on within 200 miles of owning the car at 67.3k miles for cat bank 2 (p0430) and the dealership seemed to of take care of it by putting in new cats. Now 3000 miles later around 70300 tonight on my way home from work I get the ses light and got it scanned for the same exact code as last time.

No idea how it would come back I would think replacing the whole converter would be a proper solution but clearly something is up. I am going to have a look under the car at some point this weekend but am not expecting to see anything out of the ordinary. I did notice a difference in the idle since the converters were put in and it hasn’t changed but I really didn’t think anything of it until now it could be related.

I hope they installed them properly and it isn’t hurting my car somehow (i doubt it considering people run test pipes.) The converter in there is brand new probably a cheap one considering a used car dealership bought the part but I can’t see why it would randomly bring me back the same P0430 3000+ miles later.

Any help or tips is appreciated don’t know what could be up. I can’t stand looking at the SES light while driving makes me feel like im driving a clapped beat to **** g when it’s the opposite.

 

Do you have emissions testing required?

 

Since my car is 15 years old in my state as of this year(08) I think it is exempt. I was going to get the car inspected for the sticker and they did tell me it would pass with the light

 

Most of the time I've fixed catalyst efficiency code by repairing EXHAUST LEAKS. Either at the header to engine, or the engine to catalytic converter.

Basically what happens is air has a specific weight to it (yes air actually weighs something), it comes out of each bank in a series of pulses as each cylinder fires, in between those pulses the air continues to move forward which creates a vacuum behind it that will suck air PREFERRABLY from the next piston exhaust stroke on that bank. However if there is a bad gasket at either end of the headers you will be sucking air past that gasket which is an oxygen rich air, and will cause the downstream O2 sensors to be out of spec and throw a check engine light for those downstream O2 efficiency codes.

You can use a cheapo Halloween smoke machine to smoke test the exhaust. Hook it up to the exhaust tip, tape off any other tips. Let it run 5 minutes while you visually check for any smoke pushing out past a gasket. Anything at the y-pipe or further downstream won't matter as far as your efficiency codes go. It will just create more noise. But if you're leaking on either side of the headers that would be the likely cause for that code.

You should also check your spark plugs, when they're right at their maximum gap for arc (which is way past the nominal limit of 0.043 factory gap) they can have weak fire that WILL NOT be picked up by the ECM as a P0301 - P0306 code. This can also throw an efficiency code.

Same with intake tube leaks, the ECM compensating at +20% fuel won't trigger the code for a lean condition but it can rebound your O2 sensor values (upstream and downstream) a significant margin and could also throw a code.

Dig into it a little, Seymore4 who posted the previous reply offers the Uprev e-tuning service which can definitely tune out that code as well as make the car significantly better to drive.

 

Nice post Cleric. So in your experience typically it's a leak from the headers or to the cats.

 

Well a leak SOMEWHERE yeah, smoke test intake and exhaust. It's quick and easy.

 

Ended up fixing the code brought my car to an exhaust shop and had them weld a section of my cat to my ypipe. Light went away on it’s own after driving like 300 miles.
The connection between the gaskets and cats was noticeably loose and off place on that side specifically. They recommended the other side same thing but I let it because it looked good for now.