Two codes. Need help with them.

Discussion in 'GM Powertrain' started by ippielb, May 27, 2010.

  1. ippielb

    ippielb Epic Member 5+ Years ROTM Winner 1000 Posts

    So, i got two codes on my truck, one is a P0131, which is O2 Circuit Low Voltage (Bank 1, Sensor 1). And the second code is what really concerns me. P0300 Random Misfire. I'm very concerned about that one. What can i do to try and solve these?

    I just installed long tube headers on my truck, and one the o2 sensors i needed to cut them and extend the length of the wires. And i thought, there was only three wires when i cut them, a white one, blue one, and a black one. Well it turns out there's 2 black wires. And i don't know which is what. So, its a possibility that i hooked two wires up incorrectly on the o2 sensors. I had a 50/50 chance, so i thought i would get lucky. Would having the o2 sensor hooked up incorrectly cause the random misfire? Or is that a spark plug/wire issue? Right now, my truck feels really gutless, and is burning a LOT of fuel, so i'm assuming either one, if not both of the front o2 sensors are hooked up wrong.
    Last edited: May 27, 2010
  2. MrShorty

    MrShorty Epic Member 5+ Years 1000 Posts

    The two codes may or may not be related.

    Where you suspect there may have been a problem with the new O2 sensor install, I'd probably start by making sure you got it wired in right. That seems like a good place to start. If either or both codes are still present after resolving that known issue, then we'll figure that out then.
  3. bigdogdaddy

    bigdogdaddy New Member

    yes is the simple answer. an o2 sensor can POSSIBLY cause a random misfire. hooking the two wires up wrong will give the computer a false read. did you buy a factory replacement o2 sensor or an aftermarket. sometimes aftermarket ones can be a ad bit different too...but most of the times the Bosch ones avail. at your local auto parts store work perfectly fine. Try installing the wires the opposite way if possible, perhaps adding a quick connect in case THAT is the wrong way and the way you have it is right, and go from there. From the sounds of it though, the o2 is your problem but don't hold me too it.
  4. ippielb

    ippielb Epic Member 5+ Years ROTM Winner 1000 Posts

    Does anyone know where i can find a diagram of the o2 sensors? I don't want to cut the insulation on the sensors that are in the back.
  5. dualdj1

    dualdj1 Rockstar 100 Posts

    the 2 blacks should both go to the same place (looks like the O2 heater circuit), so it shouldn't matter if they get reversed. Make sure you have a good ground (probly the white) and that your signal wire (probly the blue) has good connection.

    You can also test and make sure your sensor is working, by pulling it out, mount in a vice, and use a torch to heat the tip. should output about .6v on the signal wire (with the ground probe touching the O2 housing)

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