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my accord wont pass smog?


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p-o4200 is the code and i already spent money on a new cat and lower sensor should i replace the upper sensor as well? and yes if i cant pass i get a waiver but i gotta spend another 300$$$ to even be eligible. i'm not made of money and the dmv isn't gonna give me any kind of break. i already got the 2 allowed temp registration for ten days a piece and now i gotta pay 8 bucks a day to drive legally.

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Would you mean a P0420 code? That is standard accord speak for F U. Basically you need to replace all O2 sensors, catalytic converter, reset your ECU and pray.


Bottom line: Accord engines are pretty high strung. The systems all function with very minimum allowable tolerances to produce the power they do with the ULEV emissions certification they have. As the engines age the whole system starts to break down and just produce more tailpipe emissions. Sometimes a shiny new cat and O2 sensors can get you by for a short time but the problem is more the engine than the exhaust and the light ultimately returns 6-9 months down the road.

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Yes replace both at the same time. Your ECU judges cat' performance by collecting tailpipe data on both sides and comparing the two.


Also be sure the EGR system is clean and you have fresh spark plugs (copper unless otherwise specifically designated). Copper tip plugs burn hotter, but the trade off is the tips wear out faster. So be Johnny On Time with the maintenance intervals. If you don't have distributorless ignition, check your coil resistance.

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