I am trying to get my car inspected but I have a CEL on. Took car to Autozone and received for a diagnostic check and received a P0420 and P0411 DTC. I replaced the catalyst converter and both O2 sensors about 18 months ago with after market parts. Called dealership today and they want $1,000+ for the parts. Can I buy an after market replacement catalyst convert and O2 sensor and still pass emmission test in Texas? Does the computer need to be reset to read the after market readings from the O2 sensor? Please help. Thanks Tommydogg

 

P0411 is the secondary air injection system. Have you been messing with your intake and maybe disconnected one of the vacuum lines? A new cat won't fix this. You need to find what got disconnected on this system.
As for a new cat, why don't you try to buy a cat that someone has removed from their car when they put on a test pipe? Lots of posts here about people putting on test pipes. I'm sure one of them will sell you theirs for much cheaper.

 

Thanks,

I will look into it.

Tommydogg

 

Vacuum hose routing in the FAQ
https://www.s2ki.com/forums/index.php?showtopic=105368

 

For P0420, You might want to look into the "non-fouler" trick people do which remotes the secondary O2 sensor out of the exhaust stream. Many high performance aftermarket cats just don't work right with OBD2.

Why did you yank the stock CAT?

 

I removed the original CAT because it was defective and was causing the car to loose horsepower.

How do you make this work?

You might want to look into the "non-fouler" trick people do which remotes the secondary O2 sensor out of the exhaust stream

Thanks

Tommydog

 

I'd search the forum. You basically use two "non-foulers" to move the secondary OS sensory back from the cat.

 

Man, this reply is hard to read and understand without re-reading it. Use the "quote" button.

Here's the non-fouler thing:
https://www.s2ki.com/forums/index.php?showtopic=229959
This can be found in the FAQs at the top of UTH.

 

when I had P0411 last time, I had to replace the air-pump. after checking air hoses, check the fuse in engine bay just to make sure it's not blown. i believe it's 60A. helm's manual has diagnostic matrix for this particular problem. in case, air pump relay is bad, let me know. I have brand new one.