Did the code come back that it sensed a knock or that the knock sensor is bad? Do you remember the code? It will, more than likely, begin with a "P". Maybe P0325, P0327, etc. My knock sensor actually went bad, but I can't remember the code that it was throwing right now. If you have to replace it, the knock sensor is a bit of a bear to get to as it is buried beneath the intake manifold in the well between the cylinder banks.
I took some pictures when I replace my knock sensor, so if you get to the point of needing to replace it I can post them up if you think they would help.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless