P0420 code ??? Help

[cvcman]

CEL came on today, scanner says above code,,,car has 195k on it...how do I know IF its the convertor or the 02 sensor ??
Thx

[96 SSEi]

if you have a scanner that reads rediness, you can see if the o2 sensor passed its self-diagnostic. if it did, sensor is ok but still could be many causes

look here....http://www.easterncatalytic.com/educati ... 420-codes/

[nos4blood70]

After 195k miles, it's probably the cat.

[kc9dre]

I am at 183k and mine is doing this as well. I use Torque Pro to log the data and check readiness. I can clear it and it comes back... Cat is not clogged so I am running it as it is for now as we do not smog check and if they do they just look for codes... delete in the parking lot and pray it don't flag when tested when we did have testing here. I will eventually get it replaced when it warms up. and I replace the exhaust system...

[cvcman]

I did the spark plug non fouler mod to the rear 02 sensor,,,light has been off for almost 200 miles