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P0102 (MAF sensor low voltage)

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Macs, Jan 16, 2021.

  1. Macs

    Macs Junior Member

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    Location:
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    Vehicle:
    2010 Prius
    Model:
    IV
    After I got coolant in my intake, I got a few codes, including P0102 (MAF circuit low voltage). I swapped my engine for one with less mileage and have driven it about 50 miles since. The codes went away, except for P0102, even though I am using the MAF sensor from the newer engine. Moreover, I’m now getting P2196 (O2 sensor signal biased/stuck rich bank 1). I notice that one of the many causes of this code is a bad MAF sensor. Yet the car runs very well and I am not getting any of the signs of a bad MAF sensor, except the code. What could it be that is causing the P0102 to stay on?
     
    #1 Macs, Jan 16, 2021
  2. ChapmanF

    ChapmanF Senior Member

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    Maybe there's an open or short in the MAF sensor circuit somewhere. You used the sensor from the new engine, but the old engine compartment wiring harness, right?
     
    #2 ChapmanF, Jan 16, 2021
  3. Macs

    Macs Junior Member

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    ChapmanF, Yes, the old harness. The electrical stuff is beyond my capability as well as the mechanic who did the work for me. How do I test the plug/wiring for issues? What’s weird is I don’t see any signs of a MAF problem, though, like starting, roughness, low fuel economy, or low power.
     
    #3 Macs, Jan 16, 2021
  4. ChapmanF

    ChapmanF Senior Member

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    If you have a multimeter, or your mechanic does, one of you would start by following the "inspection procedure" in the repair manual (more info) for P0102.
     
    #4 ChapmanF, Jan 16, 2021
  5. Nphra

    Nphra Junior Member

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    Macs, were you able find out what is wrong and solution, I have the same problems on my 2011 prius.
     
    #5 Nphra, Oct 25, 2021
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