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Lost MPG After "Calibration"

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by OilManSam, Jun 24, 2013.

  1. OilManSam

    OilManSam Junior Member

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    Hello Everyone,

    My Father In Law bought a 2012 Prius C last year in Houston, they are from El Paso. The car drove great for many months, he takes the same path to work and same speed every day and was consistently getting over 60 mpg. All of a sudden winter came and he lost MPG and the engine would come on more often, even while parked. I own a 2009 Prius and told him mine did that too during the winter, because for some reason, during winter the battery drains while parked and the engine comes on to charge.

    Well it is now summer time and he is still seeing a loss in MPG. He remembered that he took it to the Toyota dealership in December and in March for oil changes and they told him they needed to "recalibrate" his Prius C because it didn't have the right specifications. He remembers that all of this started happening after the recalibration. He's thinking that maybe they calibrated it to the regular Prius specs.

    They've tested it and says nothing is wrong, but he doesn't change his driving habits but the MPG has change dramatically, he is not only getting 45-50 mpg, vs the 60-70 he was getting.

    I also noticed while driving that the battery discharges very quickly. When I parked the car to go to the movies, the battery level was 75% in green, and when I came out after 2.5 hour movie, it was purple and immediately had the engine come on to recharge the battery. I wonder if they messed with the recharge calibration or if there is some sort of electrical leakage. Anyone heard of this??

    He said he wanted to take it to Houston for them to check it out. El Paso, does not sell very many Prius, let alone Prius C and we're afraid they don't really know how to work on them.
     
    #1 OilManSam, Jun 24, 2013
  2. ztanos

    ztanos All-around Geek!

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    The PC doesn't turn purple when the battery is low...
     
    #2 ztanos, Jun 24, 2013
  3. Drdiesel

    Drdiesel Active Member

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    It's not possible to program the C with the Prius software. I would check my oil level first and then check my tire pressures.
    The dealer could have overfilled the oil or reduced the tire pressures. You might check the chassis battery too. I charge all my vehicle chassis batteries at least twice a year.
     
    #3 Drdiesel, Jun 24, 2013
  4. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    +1

    More than likely your tire pressure is low.

    As to the winter mileage there are lots of reasons. Even setting the cabin to minimal heat will cause the engine to run a lot more than usual. That is the #1 cause of lower mileage. People want a toasty cabin and don't realize the heat comes from the waste of the engine. In a normal car where the engine is running all the time, the heat is essentially free. In the Prius, the car turns the engine on and off to be the most efficient. Heat is the definition of inefficient. So the more heat you want, the lower the mpgs.

    There are lots of other factors like gas blends differ in the winter in most regions with less energy content per unit volume with extra additives. "Summer blends" are higher energy so you get higher mpg. Less fuel is required to give the same forwards momentum because the energy density is higher in the summer blends versus the winter blends.
     
    #4 2k1Toaster, Jun 24, 2013
    minkus likes this.
  5. minkus

    minkus Active Member

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    My top suspicions:
    1. overfilled oil
    2. lower tire pressure
    3. AC use/not having it set to automatic with eco mode on
    My guess for winter parked battery drainage is having the heat on, though the changes you mention shouldn't be that drastic in Texas "winter" temps (average of 50 in the winter? ha :p )
     
    #5 minkus, Jun 25, 2013
  6. ztanos

    ztanos All-around Geek!

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    We had a cold winter here in Georgia. If it was the same, I could see the mpgs he was getting being normal.
     
    #6 ztanos, Jun 25, 2013
  7. minkus

    minkus Active Member

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    What counts as "cold" in Georgia?
     
    #7 minkus, Jun 25, 2013
  8. ztanos

    ztanos All-around Geek!

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    We hit low 10s. Not Ohio weather for sure, but for Georgia that's cold. I'm from Youngstown, so I'm used to the "Lake Effect" winters, but this one was bone chilling this year in Georgia. Not sure if I'm getting used to the heat, or if it was really just this cold.
     
    #8 ztanos, Jun 25, 2013
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  9. minkus

    minkus Active Member

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    Ah, ok. That's colder than I was imagining. Our last winter's low average was 24 and high was 36 degrees. The inter before that was 30 (lows) and 45 (highs). We had 6 days with lows below 10.
     
    #9 minkus, Jun 26, 2013
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