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3 catalitic converters?

Posted: Fri Jan 05, 2018 10:39 am
by toolman69
My 04 base model got a P 0420 code so I looked into converter replacement.Over $600! Has an assembly with 2 converters then a 3rd converter? (removed).. How can you be sure all 3 are necessary? Never had a vehicle with this setup before.

Re: 3 catalitic converters?

Posted: Fri Jan 05, 2018 12:47 pm
by SeattleJeremy
The one closest to the engine is a pre-cat, then a catalytic converter, then a resonator.

You may just need the normal catalytic converter. These can be purchased for around $100 and be installed by any muffler shop. They would cut the old one out, and weld in the new one.

Re: 3 catalitic converters?

Posted: Sat Jan 06, 2018 5:40 am
by toolman69
So far I have only found the whole assembly with the pre and cat to be available.. bout 500 bucks. Then the last cat is bout $100. Exhaust smells rich so maybe an O2 sensor is to blame. CEL went off for about 300 miles and has been back on for the last 200 or so. Being careful not to go fallin down the rabbit hole replacing components that are not faulty. Seem like I see that a lot with the P0420 code issue.

Re: 3 catalitic converters?

Posted: Sat Jan 06, 2018 1:00 pm
by jolt
Do a search for " P0240 Toyota Corolla" for better info on that code and the cats. Other problems like poor spark or a worn fuel injector could cause the cats to go bad and trip that code. You need to be sure everything else is working properly before replacing the cats.

Here is a good link to read and try the things that are suggested there first: http://www.fixya.com/cars/t1056719-p042 ... ta_corolla

Make sure you have NO exhaust leaks in the exhaust system. You have cleaned or replaced the MAP sensor. You have checked the fuel trim and oxygen sensors and that the ECM is seeing the proper values. Use Denso replacements parts if needed as they are the OEM parts used in these cars.

Good luck!