O2 sensor pids

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  • paullap
    Member
    • Dec 2016
    • 64

    O2 sensor pids

    I have a 56 plate Citroen c2 1.4 petrol with the mill light keeps coming on.

    Codes
    P0138 Downstream oxygen sensor signal problem
    P0132 upstream oxygen sensor signal problem
    P0130 Upstream oxygen sensor signal

    Now the weird thing is this, I go in to diagnostics via model year ect and then in to live Data, Upstream and Downstream pids are showing 0 volts straight line as if they are not working at all.

    If I go in to obd2 live data it shows both working fine. and no codes
    I think i have a wiring problem, but why do they show something different ?.


    Paul
  • Witsend
    Banned
    • Nov 2012
    • 2942

    #2
    Sounds like that Citroen will need to go into The Giant Lemon Juice Extractor if you don't find a simple fix, like an exhaust heat shield has dropped and rubbing on the O2 sensor wires.

    Comment

    • tech25
      Senior Member
      • Oct 2017
      • 172

      #3
      sounds like a software error in the Citroen sw. normally, the obd2 data is correct and i would go with that..

      Comment

      • Glide
        Senior Member
        • Jan 2015
        • 303

        #4
        MIL is on=codes, why would you believe obd2 data if it says there no codes?

        Comment

        • Joe Rappa
          Snap-on DSD
          • Aug 2007
          • 2050

          #5
          Try verifying the voltage with a meter to see which one is correct. That'd be my next move.
          Joe
          "You don't build a reputation on what you're going to do"
          Henry Ford

          Comment

          • kirkbarrow.garage
            Senior Member
            • Jan 2015
            • 149

            #6
            Originally posted by Glide
            MIL is on=codes, why would you believe obd2 data if it says there no codes?
            Either way, the eml light is on.
            Codes or not, ( I have seen no codes and had the light on ) obviously there is a " problem with the car.
            It's French, nuff said !

            Comment

            • tech25
              Senior Member
              • Oct 2017
              • 172

              #7
              Originally posted by Glide
              MIL is on=codes, why would you believe obd2 data if it says there no codes?
              i did say normally....question.. why would the obd pids show o2 sensor readings when oem side shows nothing??

              a sure fire way i would think, would be, in obd mode, and while watching live 02 pid readings, to unplug the o2 sensors and see what readings you get.

              and, like what joe said, if you can, back probe, and confirm actual voltages, and compare to pid readings.

              Comment

              • Glide
                Senior Member
                • Jan 2015
                • 303

                #8
                Originally posted by tech25
                and, like what joe said, if you can, back probe, and confirm actual voltages, and compare to pid readings.
                That should go without saying.Diagnostic process.

                Comment

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