Check engine light - P0171 system too lean -- buy new MAF sensor?

Discussion in 'Gen 3 Prius Technical Discussion' started by Doug Hansen, Jul 13, 2026 at 4:22 PM.

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  1. Doug Hansen

    Doug Hansen Junior Member

    Joined:
    Jul 17, 2020
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    Location:
    Carlsbad, CA
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    I've cleaned the MAF sensor with the special sensor cleaning spray, and it worked for about 4 days but now the check engine light is back on and the same error code is P0171. Gemini says I should try clean the sensor contacts again, so I will, but if I need to buy a replacement MAF sensor, so I spend the $150 on a Denso or the knock - off that gets a 4.4 rating on Amazon and costs $25? Very few people have bought the OEM Denso, not sure why.
     
    #1 Doug Hansen, Jul 13, 2026 at 4:22 PM
  2. Brian1954

    Brian1954 Senior Member

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    Jan 31, 2021
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    Location:
    South Central PA, USA
    Vehicle:
    2011 Prius
    Model:
    III
    What year is your Prius, and how many miles are on it?

    In most cases, the problem is not the MAF sensor. It is an air leakage problem. Check all the vacuum hoses for cracks or splits on the end of the hoses where they connect.
     
    #2 Brian1954, Jul 13, 2026 at 5:14 PM
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