Catalytic converter



About a month and a half ago, my “check engine” light came on. My local Honda dealer told me that my catalytic converter was starting to go. They suggested I take it to another repair shop because their converters cost over $700. I haven’t gotten it replaced yet and haven’t noticed any difference in how my car runs. It’s running just fine. My check engine light hasn’t come since leaving the dealership over 6 weeks ago. Should I get it replaced? What will happen if it “goes”?



Step one: Try to get the actual error code (it will be in the format: P1234) Post the result back here. Many auto part stores will read the stored error codes for free.

The code would help, but in general a converter “goes” by becoming ineffective at doing its job and may start blocking the exhaust causing reduced power and mileage.

You appear to have a better than average dealer there, as most would have been more than happy to do the job for you. BTW the generic converter from the parts store will work as well as the OEM one.


Probably P0430…“Converter efficiency below threshold” or something like that…

Model year and mileage would be helpful…But I’ll guess something over 100K miles.

The converter may indeed be getting tired but so might the oxygen sensor that is the actual cause the light came on. The downstream sensor monitors the converters efficiency. It can tell lies. It only costs around $50…

If your converter “fails”, NOTHING will happen other than your exhaust emissions will be a little higher than they are supposed to be. If you must pass an emissions test, you will be forced to deal with this. If you are not required to “test” then you can drive on and keep your $700 ( or $500 or $400)…


Thats not completely true caddyman. I have seen converters that have melted inside and created a blockage that actually caused the exhaust flange to seperate trying to relieve the pressure. It was on a honda van that had less than 75,000 miles. I also know that many cars will lose almost all power when the converter melts and gets plugged up.

We had a customer who was convinced her transmission was shot. absolutely no power, the car wouldn’t even shift out of first gear most of the time. but after a quick testdrive found the real problem to be a melted cat.

luckily, no post cat O2 sensor so we “deleted” the offending part with a sawzall and welded in a new section of exhaust saving her about 500 bucks…


The OP did not mention any drivability issues, so I assumed he had none…

NEW converters can indeed fuse and plug up (very rare today) but after 100K miles, they just stop converting, cool down and die…


If your car has < 70 K miles the converter is under warranty. I suspect this isn’t the case as the dealer would have been happy to do the warranty work. While I am NOT a mechanic, I’ve never heard ofa converter suddenly failing and making the car undriveable- you should have plenty of warning from your check engine light which will go on and stay on. I would wait until that happens and then get it fixed, probably by the shop that was nice enough to try to save you a few bucks. I suspect they will stand behind any repair they perform.


There is nothing to “repair”, nothing is “broken”…This is strictly an emissions control issue, a moral dilemma, nothing more…


The insides of cat converters are comprised of ceramic coated with platinum-palladium (rhodium). The melting point of rhodium is 1,965C. Ceramics melt at much higher temps.

Let me suggest that if melting is occuring inside the converter then I’d be looking for why it’s overheating. I’d start by looking at the fuel metering.

I do however have to emphatically agree with you that ignoring the CEL and “driving on” is the absolute worst advice I can imagine. It can easily mask a problem that can completely destroy the engine, even cause a fire. I’m being emphatic about this because I’ve repeatedly read here this advice by Caddyman to ignore CEL warnings, and following this advice is going to cost someone big time.

No disrespect meant, Caddyman, but I think it’s time to reconsider giving everyone that advice. I think you’re a good person trying to help, but I strongly disagree with that advice.


Assuming the diagnosis is even correct, my opinion is that any service writer who offers unsolicited advice about getting it done cheaper elsewhere should be chewed on at a minimum or gone at a maximum.

If the person dishing this advice was simply asked whether it could be done cheaper elsewhere then I could see it. Otherwise, no way because service work pays the bills and keeps the doors open.