Just got a CEL last night, pulled it this morning and was greeted with a P0420 - Catalyst System Efficiency Below Threshold (Bank 1). Did a search and what I've come up with is that its most likely time to change my Cat. My questions are:

a. How do I know my cat is the culprit for sure?
b. What the muck could have caused my cat to go bad so early? I've got 30K on it with no mods.
c. Can this possibly be covered by Honda under their standard 5 year/60K warranty?

Thanks for the help

 

o2 sensor.

 

Most likely not a 02, but a broken catalyst block.

Converters are covered under federal emissions warranty for 8/80K

 

its a bad cat..since the car is stock you shouldnt have a problem getting it warrantied...

 

 

Good to hear, thanks for the input guys. Any idea how common this issue is in a relatively low mile S? I'm pretty sure I didn't bottom out or hit anything.

 

P0420 =

 

Just to follow up, dropped the car off at Honda today. She's spending the night and getting a new cat installed tomorrow for free.

Thanks everyone.

 

If someone had this code and a catback exhaust, would it still be elgible for warranty repair? Just wondering.

 

A catback exhaust has no effect on catalyst function. A N20 kit or any kind of FI with additional fuel tuning can damage the catalyst.