I got the p0430 code about 3 weeks ago but then it went away on its own after about a day. Just came back on today, wondering if anyone’s had this issue before? I know it could be spark plugs or 02 sensor or the cat but figured the sc owners would know best.
2002 with 126k

thanks

 

This is a pretty good thread on the P0430 DTC https://www.clublexus.com/forums/sc4...en-sensor.html

 

I have had the p0430 code on my SC , car was running fine with no known faults showing .
I cleared the engine warning light and code ,a few times with a code reader but it kept coming back on, at the start it would take a week and a couple of hundred miles to come back on , but then after a few weeks the engine light would come on a lot quicker .
I had already checked the exhaust for leaks and could not find any , but when i checked again later i found the exhaust was blowing between the cat flange and the exhaust flange , i put some gun gum on as a temporary fix and the light stopped coming on , well it has for now.
I am hoping it stays off , at least untill the gun gum breaks off , this would then prove its the exhaust leak giving me the code.

 

I suspect it might be the gaskets in my exhaust so that sounds like a pretty good short term fix. Thanks for the input, how long has it held up like that without throwing the code again?

 

I was getting the fault within 10 mins of clearing the code when the exhaust join was really bad .
its been a couple of weeks now and the code has not come back , I'm guessing when the gun gum fails , the code will come back . At least then I know it's not the cat that needs replacing .
I think I may have a slightly lazy o2. Sensor as well which is probably not helping .

 

The 2 sensors post cat are for emissions only. They don't affect how the car runs. Sniffers make sure you have catalytic converters. If you wanted to remove the cats they sell a little resister you plug in at each wire.

 

Your correct they do not alffect how the car runs , but they do measure what's coming out of the exhaust after the cat , if it sees abnormalities it will throw up a code .