Erratic Behavior on MPG/Mileage Display after Body Work

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by bexmix, Dec 3, 2009.

  1. bexmix

    bexmix New Member

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    I just had the rear bumper and some panels beneath the bumper replaced on my 2007 Prius. After picking it up from the body shop, I noticed some weird behavior on my energy monitor. The real-time MPG calculation appears to be working normally on both the Consumption and Energy screens, but the cumulative MPG and mileage calculation on the Consumption screen is extremely erratic.

    After driving several miles on a road that would typically produce a high average MPG, I noticed that the cumulative MPG and mileage calculation on the Consumption screen displayed that I was getting 6.8 MPG and that I had driven 1 mile. I reset the readout and started actively watching the calculations. After driving a couple more miles on good roadways, the monitor displayed that I was averaging ~24 MPG and that I had driven 0 miles.

    Does anyone have any quick tips or tricks for fixing this issue? After living without my car for five days, the last thing I want to do is have it back in the shop.
     
    #1 bexmix, Dec 3, 2009
  2. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    interesting. other than a possible flash (firmware update) for corrupted software which must be done by your dealer, there is no adjustment available.

    mileage stats are determined by measuring wheel rotations (for distance) time (for speed) and on time duration for fuel injectors (for gas consumption)
     
    #2 DaveinOlyWA, Dec 3, 2009
  3. Politburo

    Politburo Active Member

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    As a shot in the dark, I would disconnect the 12V for a couple hours to reset everything, and see if that has any effect.
     
    #3 Politburo, Dec 3, 2009
  4. bexmix

    bexmix New Member

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    After driving a bit more on both city roads and highways, I'm convinced that the body shop incorrectly reconnected my hybrid battery. I called the shop and they said they had to disconnect the battery because they were welding my car. I'm going to take it back to them tomorrow to get it checked out. Something is definitely off--the Realtime MPGs jump around like CRAZY and often drop below 10. I never saw it drop below 25 in the three years prior to the body work. Grr.
     
    #4 bexmix, Dec 4, 2009
  5. BAllanJ

    BAllanJ Active Member

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    If you mean the bar graph, maybe something is screwed up. If you mean the average, maybe they just hit reset. When there's not many miles in the average, it can vary a lot.
     
    #5 BAllanJ, Dec 4, 2009
  6. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    if the body shop reconnected the traction battery incorrectly, i would find it hard to believe that the dash did not light up like a Christmas Tree with all the codes it would have thrown.
     
    #6 DaveinOlyWA, Dec 4, 2009
  7. Bob64

    Bob64 Sapphire of the Blue Sky

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    #7 Bob64, Dec 4, 2009
  8. bexmix

    bexmix New Member

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    I have a 2007, and that issue does not seem to fit my situation.

    I'm still gathering information on the specific issues. My highway mileage seems to be more or less normal, but my city mileage is awful. When driving in stop-and-go traffic or on roads with traffic lights, I'm averaging about 7-15 MPG. Previously, I would get great mileage in these scenarios because my electric engine would take over and I'd get roughly 50-99 MPG.

    Here's a photo of the fuel consumption during my drive home from work last night:

    farm3.static.flickr.com/2547/4169706217_a58decb22a_o.jpg
     
    #8 bexmix, Dec 8, 2009
  9. bexmix

    bexmix New Member

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    Sorry, I can't post URLs because I don't yet have five posts. Soon!
     
    #9 bexmix, Dec 8, 2009
  10. bexmix

    bexmix New Member

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    Ah, here we go.
     

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    #10 bexmix, Dec 8, 2009
  11. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    not uncommon in heavy stop and go traffic. the good city mileage only happens if you can manage to move at a steady pace at something more than 20 mph...
     
    #11 DaveinOlyWA, Dec 8, 2009
  12. bexmix

    bexmix New Member

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    I have driven this car over three years and know its tendencies. This is NOT normal.
     
    #12 bexmix, Dec 8, 2009
  13. Bob64

    Bob64 Sapphire of the Blue Sky

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    Did you have the A/C (climate control) on for heat? What was your battery levels like? Was the engine on all the time?

    Edit: OH WAIT! It might be the prius re-calibrating all the fuel economy settings again. When you disconnect the 12v battery, the prius computer loses some settings that help mpg.
     
    #13 Bob64, Dec 9, 2009
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