2003 with a P3125/302 DTC

Discussion in 'Generation 1 Prius Discussion' started by pigwot, Oct 1, 2025 at 10:22 PM.

  1. pigwot

    pigwot Junior Member

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    Our 2003 has 292,500+ miles on it and started having a stumble at the beginning of accelerating from a stop. Replaced plugs and coils as it was throwing a relevant code. Also cleaned throttle body and MAF. Ran fine for a few weeks and now went into limp mode.

    Silly me took it in to the dealer asking them to do a deep scan and provide me a readout of DTCs with INFs, and Live Data. They basically gave me what I already knew P3125/302 and said, “ not worth fixing”. Over the phone the service writer had started reading the Live Data related to the DTC, but when I picked it up they did not provide a full printout, despite charging me $205 for the ‘diagnosis’…

    The P3125/302, indicates a W phase inverter voltage sensor issue as far as I can make out. Does anyone have any suggestions as to how I could further diagnose this?