1. One4U2Envy

    One4U2Envy New Member

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    SINCE I have had my Prius 2010 Model my MPG has been at 44-45 City, 47-50 Hwy. Up until recently things have been really good then I had the new software update and I swear on the hwy I cant get over 38 MPG. I went back to the dealership and they told me nothing was wrong that I should drive in ECO mode more and so on. I have lost 70-80 MPG per each full tank of gas. Any advice on what the heck is going on?
     
  2. Robert Holt

    Robert Holt Senior Member

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    That’s a large difference!
    If it were a small difference in mpg, I would suggest you recheck your tire pressures. After each dealer service on our 2012, I noticed a drop in the mpg on our 2012 and finally tracked it down to the fact that they were deflating the tires from the 40 psi I had them at to about 34 psi, which seemed to decrease mpg by a small but noticeable amount.
     
  3. Mendel Leisk

    Mendel Leisk Titanic Social Director

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    Do you have any documentation, name/description of the update? I'm guessing it's the second update related to the inverter?

    We had that on our 2010 this spring, and I noticed "some" mpg drop thereafter. However, also put on new tires around the same time, and that's my number one suspect.
     
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  4. bisco

    bisco cookie crumbler

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    welcome!

    if you search here for the update threads, you will find many similar complaints, but no solutions. not sure why
     
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  5. Grit

    Grit Senior Member

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    It’s to keep ICE on longer and reduce inverter workload so it doesn’t overheat and die putting your life in danger on the highway when you are rear ended at 65 mph. Easy peasey.
     
  6. Grit

    Grit Senior Member

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    It’s to keep ICE on longer and reduce inverter workload so it doesn’t overheat and die putting your life in danger on the highway when you are rear ended at 65 mph. Easy peasey.
     
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  7. frodoz737

    frodoz737 Top Wrench

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    Look at it like what happened to the Insight GEN I. The design was over using the hybrid system/ battery and was later "detuned" to allow things to work longer. The result was a hit to mpg...same here.
     
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  8. bisco

    bisco cookie crumbler

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    i wonder if you drive like a granny, if it has any effect
     
  9. Mendel Leisk

    Mendel Leisk Titanic Social Director

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    That sounds plausible, and some have reported that, but personally I didn't. There were two inverter-related software updates right?

    I recall after the first one, a few owners were having serious mpg impact. But it apparently was due to poor TSB instruction from Toyota, the software update not applied properly/completely? @ChapmanF had some ideas on this.

    FWIW, I never noticed a mpg drop. If anything, it seemed like post-update the car had a slightly greater propensity to slip into electric-only, and accordingly mpg went up slightly.

    Now after the second update, I might have experience some mpg drop, a minor amount. I'm not sure, cus I put on new tires around the same time.

    Going back to our snow tires this fall, our mpg has improved lol. So I'm going to put most of the blame on tires. But I've got a hunch there was a slight cross-the-board drop in mpg due to the software. Maybe.

    We had an 06 Civic Hybrid, similar story as Insight I think, what a debacle.
     
  10. One4U2Envy

    One4U2Envy New Member

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    Yeah it was the second update. Did you have them check the inverter?
     
  11. Mendel Leisk

    Mendel Leisk Titanic Social Director

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    I just got the software update. I think it was all good, and my mpg drop is due to tires.