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  1. #1

    Question Silverado Knock Sensors!

    I own a 2000 Silverado Z71 3dr ext cab 5.3L and my SES light came on. i checked and i am getting back code PO327 and PO332 (knock sensor circuit, low output). what is the easiest way to determine if the actual knock sensors need to be replaced or if its the knock sensor harness connector?

  2. #2


    Well if the sensor came up on scan. Replace it first its a $40-$50 part. TrailLeadr found it for $44. I found this at NAPA.

    Don't read to much into it. A 2000 should hardly have a wiring problem.
    Good luck, Brother.


    2007 Ford E250(Work van) (Ya, Ya, shut up!)
    1996 GMC Sierra SLE 1500 5.7L/4L60E

  3. #3


    Thank you for the help. Anyone know how hard it is to get to the knock sensors and what tools are required. I'm pretty sure they are under the intake manifold, which doesn't sound like fun.

    2000 Chevy Silverado 1500 Z71 3dr ext cab 5.3L V8

  4. #4


    They are under there, but can't help you with tools. Sorry, Never done one on a 5.3L

  5. #5
    Newbie Oldbear's Avatar
    Join Date
    Aug 2007
    Strathmore, Alberta, Canada


    There is a bullentin on that from GM (where I work) "0332" is a ground fault in the knock sensor wiring set off by moisture (there are two, but it won't tell you which one). Easy to get at - just remove the intake manifold, the sensors sit in a metal valley pan. Don't remove the pan, just the boots over the sensors and the sensors themselves. Put in new sensors, silicone between sensor and boot and wire and boot. Replace intake manifold, with new gaskets - your in there anyways... And your code should stay cleared.

  6. #6
    Newbie Oldbear's Avatar
    Join Date
    Aug 2007
    Strathmore, Alberta, Canada


    And yes, you will need a tool to disconnect the fuel supply line from the fuel rail. But, other than that - nothing but an average tool kit. Ask your local GM/Chevy dealer for a few pictures of the intake manifold and knock sensor locations. Any nice parts guy will do it for you, maybe with a coffee or dounut... we parts guys work for these all the time
    Drive it like you pay for it...

  7. #7
    Legend unplugged's Avatar
    Join Date
    Sep 2006
    High Deserts of SoCal


    Some info that might help:
    From: Allexperts
    Why are they suggesting the replacement of a Knock sensor?
    Is the Check Engine light on?
    If the check engine light is NOT on, there is NO reason I can think of to replace the sensor.
    If it is on, I know the GenII engines (1999-2002) had a problem with water getting into the knock sensor mounting holes, and creating codes due to short circuits (Code P0332) for the REAR sensor ONLY. If you have a code P0327
    that is for the front sensor ONLY. No need to replace them both. If you happen to have a code P0325, this code means that someone, somewhwers replaced the PCM (computer) and did not swap the Knoch Sensor Module into the new PCM computer.
    Testing...Remove the intake manifold sight shield.
    Disconnect the knock sensor jumper harness connector located on the left side of the intake manifold.
    Set the DMM to the 400K ohm scale.
    Measure the resistance of the appropriate knock sensor using the DMM connected to battery ground.
    Is the resistance of the knock sensor between 93 and 107k ohms.
    If so the sensors are good
    If not Connect the DMM between the appropriate knock sensor signal circuit on the sensor side and the engine block.
    Set the DMM to the AC voltage scale.
    Important: Do not tap on plastic engine components.
    Tap on the engine block near the appropriate knock sensor while observing the signal indicated on the DMM.
    Is any signal indicated on the DMM while tapping on the engine block near the knock sensor?
    If so check all wires to PCM.
    If not replace sensor(s) for the code set.
    I hope this helps.
    JUST advice from experience.
    Good Luck
    There is no way to happiness....happiness is the way.:yipi:  _vXMYypuKMJFw671uF2ZPhjez_j-atRmcjM2zQKpQi1JSsB75/burb1.JPG
    High Desert SoCal
    93 K1500 burb (personal) 350 AT 3" Lift 250K+
    02 Honda Civic LX
    Looking for a 1990's Miata for an engine swap

  8. #8


    Hi, let me just add, I just replaced my knock sensor#2 two months ago, with silicone, and got an alarm again. It, and #1 had 100k-ohms, and 0.2V AC when knocked with hammer on block's side (suppose to be 5V, but digital meters never show spikes). I took off the upper manifold again, and found the #2 sensor was rusted again. I asume water is running down the wire, so $50 later (because I did not want to trust a rusted sensor even though it checked out) I replaced it and siliconed everything. A few things I learned: don't use anti-seize (the voltage is weak already), tighten to 10-15ft/lb, and double check that the well is clean of all rust and water (it is hard to see, unless you jump on your engine). Good Luck.

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