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Long story short, bought a car from this Honda Service parts manager and car was great after I test drove. Go to pick up car then next day and I'm driving home and the check engine light comes on. I go to Autozone and they check is and the code is P0420 which is catalyst system efficiency below threshold bank 1. I text the owner and he acts stupid about the whole thing saying it was fine when he had the car and what not. I'm guessing he cleared the code...

Okay point is I was looking into replacing the catalytic converter but the previous owner put in a OBD1 D15b on the car instead of the OBD2 D16Y8. Should that be a problem? I know they're two different computers, will I have problem passing smog if I replace the cat and the light still doesn't turn off? He just swapped the engine and tranny, he said he kep the original exhaust system on the car. Really lost and feel like an idiot for not driving the car longer to see that light pop off.

tony_2018

Follow the car's design, what ecu is in the car? If you don't know go check, take a picture of it if you don't know what it means. White rectangle label on the side of the ecu, which is located in the kick panel passenger side.

eghatch9295

iTrader: (1)

you can do the spark plug non fouler trick to pass emissions. google it.

98EGY8

i may be totally wrong here but wont you fail for having an older engine in a newer car

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eghatch9295

iTrader: (1)

that is the correct ecu. your car was also at one time automatic.

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m

Yeah previous owner swapped it with the older engine. Just worried about that cel cause I need to register my car and need to pass emissions to register it.

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Is there a diy? Seen a lot of them on here. Btw here's a pic of my cat lol.

eghatch9295

iTrader: (1)

DIY O2 Sensor Bypass / Spark Plug Non-Fouler Trick Installation (w/ pics) - Honda Civic Forum