1. Welcome To GMTruckClub.com!

    The #1 Chevy Truck Forum Online
    Online since 2004, we are the #1 Chevy Truck & SUV forum and user community. If you have any questions about your Chevy or GMC Truck, SUV or Crossover, or just want to connect with other GM owners and enthusiasts around the world, you've found the best place on the internet to do that.

    Join Today ~ It's Free
    Registering is Free and Easy! Hope to see you on the forums soon!

Codes 42, 43, 44

Discussion in 'GM Powertrain' started by clifton, Oct 12, 2009.

  1. clifton

    clifton New Member

    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. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

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

    clifton New Member

    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.

Share This Page