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So, I got in my car this morning to go to work, Boston Vovlo, and I saw my Check Engine light was on...I had one of the techs check with the diagnostic machine to see what it was and he told me it was the Knock Sensor. He said that it goes off if it senses any knocking or pinging in the engine. I haven't heard or felt anything out of the ordinary while driving. So, my question is, what is it, and should I be worried about it? He was able to turn the engine light off.