Checking up on my gf's car the other day I noticed that her knock sensor was busted, but she isnt throwing any code of any sort. Will a straight grouded knock sensor not detect a problem and thus not throw a code, or whats the deal there? I intend on replacing it tomorrow when I am off of work, but I am just trying to make sense of why it wouldnt throw a code while my sisters f22b with p14 ecu throws knock code 24/7...