The probability of it being the converter is high. Although, this other thread is regarding a Honda Pilot, it similarly applies to the Accord regarding P0430, some of the guys are actual Honda techs:

"http://honda-tech.com/showthread.php?t=2961066&highlight=p0430"

My opinion is the converter has lost efficiency and that the car's computer has detected it is no longer working within acceptable parameters. Does that mean that it won't pass an emission test? Yes and no; it won't pass in most States since the Check Engine Light is on; however, the actual exhaust emissions may actually be within acceptable emission levels. On older cars, if the convertor is real old, that is another story.

The problem is not as prevalent in Hondas; but, more prevalent in many older Toyotas. Many older Toyota required a converter replacement or people installed illegal rear O2 simulators. On certain Toyota Camrys, the dealer had software updates which essentially raised the threshold before a pending trouble code was stored, which may result in a Check Engine Light if the same trouble code is detect in two consecutive drive cycles.

 

It was a P0430. We live too far from the dealer. I don't know of a way to check the efficiency of the sensor on a bench, only if it sense or not. I just paid 90 bucks for a sensor and put it in. Took a chance and it paid off. Common result for that mil code.

 

Wunderbra, thanks for the info.

Redbull, I read that Pilot thread. Thanks for the nice resources. Sounds like some people there are very adamant about the accuracy of code P0430 and I'm sure they are saying it as it is.

By the way, I did a silly test: I smelled the exhaust while the car was running (I'll make up for it by breathing some fresh air in the early AM). I did not smell a thing and my nose is definitely working.

 

So, I bought all the tools and equipment needed to replace the catalytic converter myself this weekend. As I was driving home tonight, the MIL light went off on its own. It was likely the fuel cap, which I tightened 5 days ago after reading some tips online.

To think that I was almost convinced to pay a $1,100 job to fix nothing by my local Honda... I am fuming. I'll call the manager tomorrow to express my discontent.

Even though the "adviser" said he guaranteed the mechanic did the analysis needed to make sure the issue is with the catalytic converter, I highly doubt they did anything. At least they could have the decency to suggest that I wait a while before committing to the job, but they did not do that. I cannot imagine how much money they have made this way. Absolutely enraging.

 

Let me give some perspective. Generally, a loose gas cap will not set a code P0430, it may set a code P1456.

You have what Honda terms an "intermittent failure" which means a system may have had a failure, but checks OK now. If the check engine light was on but then went out, the original problem may have been intermittent.

On many cars, depending on the type of failure/problem detected, the computer will store a pending trouble code the first time it is detected and no check engine light will be on. If the same failure is detected on 2 consecutive drive cycles, then check engine light comes on. The check engine light may turn off after several other drive cycles if the same failure is no longer detected.

What this means is that on your car it is was an intermittent failure. Does that mean it will come back? Possibly, yes or no. So, just drive as normal and if the check engine light comes on again, read/scan for the code(s) to see if they are the same or one or more different one.

 

Thanks Redbull. Sometimes a different perspective can save people from doing stupid things. But I think I am not unreasonable this time for bashing the dealership. They have to know about this "intermittent failure" phenomenon, and they should have considered that as a possible cause when looking at my car's record, which shows (as mentioned in my original post):

1. It has 90k miles
2. It passed inspection a month ago (at that point)
3. It is a hybrid

What are the chances of the catalytic converter failing here? And being a knowledgeable "advisor" with MY best interest, they should have told me about this "intermittent failure" possibility and advised me to wait for a week or two. It's not as if driving around with an inefficient cat will damage my engine or anything. I'm still very disappointed with their service.

Edit: the inspection was an emission inspection, done at the very same dealership.

 

I found the service advisers are a mixed bag even at the same dealership. I found some advisers do not really know about many specific problems, it is usually the more experienced techs at the dealership that would know. Some advisers are more knowledgeable and objective. But, this is just like how people are in the general population. Some advisers are not doing it in your best interest.

Does that mean your adviser is being dishonest or just not knowledgeable? Sometimes is may be one or the other, or a little bit of both. The best course of action was to clear the trouble code and advise you to drive it to see if it comes back.

I really can't say whether the code for the cat converter will come back. For example, years ago on my dad's Toyota, it came up with a code P0420. I cleared the code first, it came back. I then tried replacement of the two oxygen sensors on his car, the code went away for a year after that. Later it came back and stayed, so it turned out to be the cat. Now, a friend with a different Toyota model had the same code, I cleared the code for him; but, warned him it may come back. My friend did nothing and waited and waited. Over a year later, he told me it still hasn't come back. I haven't checked with him after that. But, this just gives you an example, that situations may not be identical.

 

Thanks Redbull. You're right, maybe I'm expecting way too much. After all, they have their own reasons for doing what they do. I can't say I would never do the same thing were I in their shoes.

This was definitely a good experience to have. I hope my story and your comments here will save readers some money.