I have a 2013 Fit Sport, 276k miles, I drive ~600 miles a week. About a month ago I was driving on the highway and a solid CEL came on, code P0420. Car felt sluggish so I took it to a mechanic who kept my car for a few days, said they "couldn't recreate the problem", that the light was now off, and if it came on again I might need a new Cat and 02 sensors. Got an oil change (it was overdue by a few thousand miles which I thought may have contributed to the issue) Ran a bottle of Cataclean through the fuel tank, and it has been fine since - until today, a month and a day later. CEL popped up but car felt fine so it took me a while to even notice it, same code. Called the mechanic and they said most likely need to replace the Cat and that I should plan to replace the 02 sensors as well.

To keep the price down I want to purchase my own parts, but not sure what parts I need. Mechanic can't see me until next Tuesday but said I could bring it in and they'd verify which parts I need. Is it worth finding a used Cat or just buying brand new? Is Rock Auto the best site for parts? I want to keep my Little Fit running for as long as I can...

 

From my experience:

- Don't buy a Bosch sensor. Buy Denso or NGK (OE brands if I remember);
- If you buy an aftermarket cat, your CEL might come back in a while. On my older Civic beater, I had to add an O2 sensor extension to back out the sensor from the exhaust because the cat was not effective as the OE. Otherwise, I would have a CEL...
- If you do the above, you'll probably need an O2 sensor extension wire.

 

Com esse P0420 em uma Fit com 276k milhas, o mais provável mesmo é catalisador cansado ou começando a perder eficiência, ainda mais se o código voltou depois de um mês. O carro ainda pode andar “normal”, porque o problema é mais de eficiência de emissões do que falha mecânica imediata.Sobre peças: eu evitaria catalisador usado. Quase sempre já está perto do fim da vida e você vai acabar no mesmo problema de novo. O melhor custo-benefício costuma ser um cat novo aftermarket de boa marca. Sensores O2, em geral, só valem a troca se o diagnóstico mostrar leitura lenta ou falha, não só por precaução. Frank Casino Portugal destaca-se pelo design elegante, bónus https://frankcasino-portugal.com/ generosos e ampla seleção de jogos.