Hey all,

I have a 2000 Civic DX and the other day my cel came on. I did the ghetto paper clip trick to get the code and I'm getting a 65 which is a secondary heated O2 sensor circuit fault. The car seems to be running the same as it was before the cel came on and I was just curious that if I just leave this thing alone will it cause any damage to my car. Also, is this the same O2 sensor that goes right after the cat? Anyways any help would be greatly appreciated. Thanx!

PROBABLY wouldn't do any damage... but still you should either change it yourself or get it changed all the same.

if it is the secondary then yes it is the one behind the cat. it might not be all that bad right now, just bad enough for the computer to catch that it is not working entirely correctly, but it will get worse the longer it goes