So I've been reading some posts about this code. The code means "Catalyst system efficiency below threshold" for those that don't have the numbers memorized.

From peoples' comments, it sounds like if it is the cat, I shouldn't just ignore it because it could lead to engine trouble.

So how do I know if it's the cat, as the dealer of course will claim, or if the sensor is just bad?

 

either one is rather expensive. My personal idea is that it's more likely to be the O2 sensor if you're car is OBDII........since those things tend to go out a little too often. Does the code throw immediately upon starting up?

I'm guessing you don't have any form of high flow cat........the cat if it's melted on the inside should be pretty obvious....pull it off and look at the catalyst element.

- Nathan

 

Yes, the light is pretty much always on, from the get-go. I used to like getting dirty, now I'm lazy...but I don't want to waste $800 on something I don't need, so I guess I'd better have a look myself. Thanks Nathan

 

I have a 98 4cyl accord and the cat just went like 3 months ago and luckily I was able to replace it under warranty. (even though my car is not under any dealer waranty)

All cats are supposedly covered till 80,000 miles (regardless of dealer warranty)....so if you have less than 80k on the clock you can get your cat and O2 sensor replaced for free from Honda as I did. Dunno if this info is relevant to your case, just thought I'd pass on the info.

 

I'm at 127K, so no freebies. I'm going to let the dealer replace it because the service advisor promised not to charge me unless the problem is solved.