2000 Quest codes 324 and 305 knocking sensor?

What is your question?

I have a 2000 quest check engine light came on flashes then stays on sometimes flashes again(as if to remind me somethings wrong). Runs fine, no loud noises, just a slight squeaking sound around the belts - I think.when driving it and i get to a steady rpm you can barely hear the squeaking. the guy at oreilly's said that i need to replace the knocking sensor but I want to be sure before I spend that kind of money.