So my check engine light went away.. is everything good?

[Greg Lee]

06 expedition AWD. 130k miles. Check engine light has been on for two days with following code: p0420 catalyst system efficiency below threshold bank 1.

I was gonna take it in to get it fixed when all of a sudden the light disappeared. So.. is that normal and should i still get it taken in for fixing? Also, what exactly does this code mean?

Thanks!

 

[JuniorExp03EB]

might be your Cats.

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[JuniorExp03EB]

check your o2 sensor switching too. do you have Forscan?

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[stamp11127]

That is an emissions related code. Basically means the exhaust is "dirty" as compared to a system that is within specifications.

FYI:
https://www.obd-codes.com/p0420

Since you are in Cali, you will be taking care of the problem eventually. Sooner is usually lower cost than later.