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service engine soon light

Discussion in 'Chevy Trucks' started by flanny0104, Oct 27, 2008.

  1. flanny0104

    flanny0104 Junior Member
    from indiana
    Messages: 17

    02 chevy 2500 hd, my light came on and i was told it is a knock sensor. now the truck runs great, no loss of power or bad gas mileage (well no worse):D. it is located under the intake manifold and is a $40 part but will cost $400 to fix. i am thinking it is just a bad sensor but not sure if ignoring it is really the way to go. any one else seen this?
  2. ChevKid03

    ChevKid03 Senior Member
    Messages: 505

    Not only have I seen this but I've dealt with it. The problem MORE THAN LIKELY is your rear knock sensor is submurged in water. The sensor eventually "rots" and starts not working correctly. The part isn't THAT difficult to remove and replace granted you have some regular tools, a torque wrench and some new gaskets to button it back up. I would do some research on here and search for "knock sensor". It will give you the rest of the lowdown. Goodluck!
  3. ahoron

    ahoron Senior Member
    from here
    Messages: 422

    I had to replace mine. when you replace them build a dam of silicon around the holes and leave a spot open at the rear. mine was the rear but i replaced both since I was already in there. there is a service bulletin for it from gm.
  4. Bigb40319

    Bigb40319 Member
    Messages: 30

    recently replaced mine also wasnt a bad job at all i got complete instructions off all data