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display shows 3.6 miles per gallon

Discussion in 'Gen 2 Prius Fuel Economy' started by TimComeau, Jul 23, 2023.

  1. TimComeau

    TimComeau New Member

    Joined:
    Jul 22, 2023
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    Location:
    San Diego
    Vehicle:
    2008 Prius
    Model:
    Plug-in Base
    New 12V battery installed. Engine starts. No dash display, no back up camera. "Energy" display with flow between battery and engine looks normal. "Consumption" display shows 3.6 miles per gallon. Why so low?
     
  2. Tombukt2

    Tombukt2 Senior Member

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    Durham NC
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    2009 Prius
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    Base
    I don't know did you just fill the tank up 3.6 mi from the house? No display etc etc Is this a normal occurrence It's normal for this type of car but for this particular vehicle and yourself so the display comes back every so often every few starts to display comes back stays on for weeks etc? I've been dealing with this for years I've had four different displays in the car from $300,000 mi old to 92,000 mi young all of them do the exact same thing It's very difficult for me to believe some capacitors on the board are out of spec.? My display always comes back always people have said when it's dead it's dead mine's never been dead for longer than say 48 hours I don't think the 3.6 mi and what not is related If mine was showing that and it's now not moving so in other words if you go out and drive that mileage will not go up or down or do anything You will also not have your trip meter showing and I don't think they'll be clocking mileage because your display is off so you have to know how much gas is in the car and use your phone to figure out your miles per gallon or miles till you need to get gas but my car will come back on before that becomes critical and I know what's in the car and all that. That 3.6 mi I guess is where everything turned off.?
     
  3. TimComeau

    TimComeau New Member

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    Jul 22, 2023
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    Vehicle:
    2008 Prius
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    Plug-in Base
    Well, good news. After trying several youtube "tricks" without success AND checking fuses, etc. , I disconnected the 12V battery YET AGAIN. This time for about 5-7 minutes. Got my gauges and back up camera to function again. Gas gauge shows a full tank, which it should. I assume the 3.6 mpg was a bad reading because of the electronics.
     
  4. Tombukt2

    Tombukt2 Senior Member

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    Vehicle:
    2009 Prius
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    Base
    Yes so you just have the failing display problem now what you need to figure out is does this continuously return You should not have to be resetting and undoing the battery to make this happen. Generally speaking that is I never have disconnected my battery to reset my heads up display or any of the lights on the dash usually playing with the push button or doing nothing just driving to my next service call parking the car coming out from that service call and starting the car all the dash lights come back on and now they might stay on for 2-3 weeks. Then one morning I get in my car the minute I push the brake and push the button if I don't see my display immediately I push my button immediately in the car is off and then I push the brake and hit the button again and the display lights up like it's supposed to and I'm backing out of the driveway this is how it's been going for the last 3 years with this 09 that I drive 100 plus miles daily this exact scenario exactly. I have been told by people that it's a capacitor on the board I've had four different displays in this car from a little old lady's 94,000 mi perfect condition Prius with a dent in the back that went to LKQ all the way to 340,000 mi pieces of work junk that you wouldn't want apart from that car anywhere near your vehicle All of the displays have displayed the same exact properties discussed right in this text. I do not believe the capacitor business but I'm not in any situation to prove or disprove anything It doesn't really interest me but having all these displays in my car and trying to believe that all these displays show the same problems I have a real issue with that I do not believe that but that's just me My display works everyday and when it doesn't it's back on a few minutes to a couple hours at best before I can even use a quarter of the tank of gas in the car the displays back on so I just don't fool with it.
     
  5. avoice217

    avoice217 Member

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    Location:
    Texas
    Vehicle:
    2009 Prius
    Model:
    II
    Yep I had a similar issue where the 12v battery terminals weren't connected properly, but instead of failing dashboard of faulty mpg info, my car just wouldn't start at all. Finally had to take the battery itself back to O'Reillys & get a new one since it was under warranty. However, as soon as I get enough $$, I'm gonna invest in a Toyota OEM battery. Unfortunately the warranty on this won't last for more than a year. However, I noticed that the terminals can be super finicky if they're not completely on the nubs of the battery itself.
     
  6. dolj

    dolj Senior Member

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    I wouldn't bother until the replacement dies.

    Ensure you undo the terminal nuts quite a bit then use a large screwdriver to wedge the clamps open. Place the widened clamps on the terminal and ensure it sits all the way down to the bottom of the terminal post. If you can't get to the bottom, widen the clamp some more. Do the clamp up with a socket or the closed end of a box wrench all the while placing downward pressure on the clamp to hold it in place. So many people lever the clamp up using the open end of a box wrench.