Huge MPG Loss

Discussion in 'Prius c Technical Discussion' started by CMJAnew, Jan 2, 2026 at 9:45 AM.

  1. CMJAnew

    CMJAnew Member

    Joined:
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    Vehicle:
    2012 Prius c
    Model:
    Two
    I haven’t eliminated the EV system….however, having driven C’s for better than 600,000 miles combined (three cars) I’ve not experienced an MPG loss like this - WELL OVER 10mpg loss happened pretty much overnight - but not last night - LOL
    I have eliminated brake drag and wheel bearing issues. The car has new spark plugs and air filter.
    There is a noice that sounds similar to ‘traction control/stability control’ activation coming from the passenger front only when the ice engine is activated. At least that is where I believe it’s coming from.
    Also, when watching the onboard “home” screen it seems to get extremely poor mileage - like 35ish mpg at 65mph (history says it should be getting closer to 50 than 40 at those speeds).

    ThanksMuch, and happy new year
     
  2. bisco

    bisco cookie crumbler

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    so you're not tracking it at the pump?
     
  3. Mendel Leisk

    Mendel Leisk MMX GEN III

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    The dash display, albeit skewed, is at least consistently skewed.

    Any new tires in the mix?

    Gas up somewhere other than the usual?
     
  4. bisco

    bisco cookie crumbler

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    12 volt or hybrid battery weak?