I'm getting the reduced-performance message and a code for knock sensor. Car still drives reasonably, so presumably just has less spark advance.

Anyway, while I get around to buying a new sensor, I was just wondering whether the knock sensors actually deteriorate in some physical way, or do they just get dirty and get dirt in their connectors? That is, if you removed them, cleaned them carefully, cleaned out the connectors and put them back in, would the fault go away?
As I understand it, they are a ceramic piezoelectric stack, which I would think would be impervious to anything but a direct whack.

Anyone have knowledge or opinions? Experience with failed sensors which clearly looked bad to the eye?

Mostly just curious!

 

Yes the sensors deteriorate. The center of the sensor becomes 'gooey' and a tar-like substance is visible where the harness exits.

bob gauff