What Problems Go Along With Bad Catalytic Converter

Question: What Problems Go Along With Bad Catalytic Converter,
I’m pretty sure our catalytic converter needs to be replaced – been diagnosed that it’s probably the cat, no power, it seems to add up. I can get it fixed for about 100$. My question is – the check engine soon light is not on (which I have been told is weird) but I want to know if there are other areas/parts that should be checked or possibly replaced/problematic. Please help!
thanks for the info. the lights all light up when i start the car so nothing is burned out. i will talk to my mechanic about the o2 sensor – for you mechanics out there, do those 2 things (cat and o2) go hand in hand or will i need to specifically ask him to check or replace the sensor? can anyone think of anything else to be aware of checking or that may contribute to the problem? the temperature before and after the “honeycomb” is only 10 degrees different (i guess it should be about 100 degrees) so it’s definitely running really hot. i just wonder if there is anything else contributing…. i know it’s hard to know if you’re not looking at the car 🙂
wow – you guys are great. it’s an 03 Saturn L200, it has a salvage title (which i knew when i got it…. ) that’s not a problem, i’m confident with the work and the mechanic that rebuilds them. i just wanted your opinions to feel confident that it’s PROBABLY just this problem, which would be fantastic news. Does anyone know if the federal emissions warranty someone mentioned covers a salvage title? we were told by the seller/rebuilder and the saturn dealership that there was no warranty coverage due to the car history (being in an accident). anyway, any extra info would be great. thanks again!

Best answer for What Problems Go Along With Bad Catalytic Converter

A bad catalytic convert will set a MIL on an OBD-II vehicle, ’96 a newer. That was part of the new OBD standard….if it’s ’95 and older it won’t.

Generally one of two things happen with cats…they either become contaminated and stop filtering properly or they get clogged – the latter is evident by power restrictions and an extremely hot catalytic converter. The cats are down stream in the exhaust, so there is not much of anything they can affect on the car when they go bad. If they need to be replaced, you can have them changed out and shouldn’t need to worry about anything else with the vehicle (related to this part.)

If the car is less than 10 years/100K miles, you can get them replaced for free under the federal emissions warranty.


I’m not sure about the salvage title part…there would definitely be no manufacturer’s warranty for that, but it is my belief the federal emissions warranty should still apply – you may have to do some arguing. It would probably serve you best to call a few dealers first and try to locate a cooperative one.

My mistake, its 8yrs/80,000 miles…not 10/100…I know I’ve seen that number somewhere, maybe a manufacturer’s extension. See the link below for more info from the EPA.

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