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  1. #1

    Default Codes 42, 43, 44

    code 42- electric spark timing
    code 43- Knock sensor circuit
    code 44- 02 sensor- lean exhaust detected

    These are the 3 codes I am gettin on a 91 Chevrolet 3500HD with a 454. I went to looking for the kock sensor which I thouht was on the passenger side of the engine just around the starter, thats where it is on my other pickup and there is nothing there. I have a plug coming out of the harness on that side of the engine with 2 green wires, is this the plug to it? Is the knock sensor supposed to be on that side in the coolant gally? The only sensors I can find are one behind the harmonic balancer on the oil filter side that is long and cylindrical which I am pretty sure is the oil pressure sender, the other is in the head on the oil filter side which is the tempurature sensor. I cant find the knock sensor for the life of me, if it doesnt have one I am sure that is why all the codes are popping up. The guy that had it before me really jacked this pickup up bad. Any information would be a big help.

  2. #2


    The knock sensor should be on lower right<passenger> side of engine under exhaust manifold according to Mitchell.

    2004 SILVERADO 2500HD LS
    Pro Comp Leveling Kit
    285-75-16 Cooper ST All Terrains
    Pro Comp Programmer
    Bilstein Shocks
    Linux Bed Liner
    Tinted Windows

    Other rides:

    1967 Landcruiser <350 Chevy>
    1970 Camaro
    1990 Geo Metro Convertible
    2007 FJ Cruiser

  3. #3

    Default knock sensor

    Thanks for the feedback, this thing has no knock sensor, I have been all over both sides of the engine and found nothing. I went and got a book with the wiring diagrams and found the wire but no sensor, I am gonna go out on a limb and say there are my codes. I appreciate the info, thanks.

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