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How to reset the Average MPG on main display

Discussion in 'Gen 4 Prius Technical Discussion' started by Tikki000, Jul 21, 2020.

  1. Tikki000

    Tikki000 Junior Member

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    I own a standard Prius 2020. So for some reason the Avg MPG on the main (leftmost) display (under the speedometer readout) doesn’t not appear to be moving up even though I am averaging 60ish MPG per day (based on the diary). It is stuck at 54.7 and doesn’t move. Is there a way to reset that number so it uses the average for the past 4+ weeks?
     
  2. Tideland Prius

    Tideland Prius Moderator of the North
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    Are you showing ODO, TRIP A or TRIP B numbers?

    Hmm, isn't the average MPG display a small arrow on the instant FE gauge to the right of the speedo?

    If you're talking about under the speedo, then you have to hold the TRIP button on the steering wheel to reset the value.
     
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  3. alanclarkeau

    alanclarkeau Senior Member

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    As Tideland Prius indicated, there are 4 different figures. The ODO one which I suspect you're looking at will sometimes almost never move. Mine has read 4.0 for several years.

    I use TRIP B for ... trips. Like if I'm away touring for a day/week/month and want to know how I went for that period.

    With TRIP A, I reset that every fuel fill.

    Or - put up the ECO DIARY:

    upload_2020-7-22_11-52-20.png
     
  4. jerrymildred

    jerrymildred Senior Member

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    The mpg display you're talking about can be reset by having the ODO on total miles (as opposed to Trip A, Trip B, etc.) if that's what you want to reset. Then just press & hold the Trip button on the steering wheel.

    How many miles on the car? The more miles you have on the car, the longer it will take to move that number. And the difference between 54.7 and 60 is small enough that it's not going to change very fast on that account either.

    Example:
    I got my Prime in March last year with 23,000 miles on it. It was only reading about 50-60 mpg. I reset it when I got it. I drive mostly EV around town, but we took it on a 6,000 mile trip that May. When we got home, it was reading about 77 mpg with about 31,000 miles. It's now at about 44,700 and only up to just over 128 mpg even though I'm averaging 200-300 mpg since then. It changes slowly when you are starting from a base of 8,000 miles.
     
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  5. alanclarkeau

    alanclarkeau Senior Member

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    Ahhh - I didn't realise that the overall ODO could be reset. But why would you want to - isn't that what TRIP A and B are for?
     
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  6. jerrymildred

    jerrymildred Senior Member

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    It doesn't reset the ODO; it resets the total MPG. I wanted my MPG record, not that of the original owner who was getting incredibly bad gas mileage.

    Here's what the PO had in December, 2017-March, 2018 for example:
    2017_11-2018_03.jpg
    And that's on a Prime!!! Had I not reset the total MPG when I got the car, I'd have no clue what my average was from reading the car's numbers since they'd be so heavily weighted by the PO's 23,000 miles of sub-50 mpg driving.

    My diary has been pegged at 199.9 mpg every month I've owned it except May this year and May last year. Actual, calculated from L/100km is estimated at 300-700 mpg. (May last year had a 6,000 mile road trip. May this year, I worked from home, so much of my driving was beyond battery range.) So I want my ODO to reflect what I'm actually doing rather than want Mr. Foot in the Fuel Injector did while leaving the EVSE cable in the bubble wrap.

    The main point is that after the hit from a 6,000 mile trip at 56 mpg, it takes a long time to recover from that average to a new average even getting vastly better mileage now than on the trip. :)
     
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  7. alanclarkeau

    alanclarkeau Senior Member

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    Yes, that makes sense. But in my case, I'll leave the l/100km for the ODO alone - because I'm the only driver.

    My dog reckons that in dog years he's senior to me now - but no, he doesn't drive - just supervises from the back seat..
     
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  8. jerrymildred

    jerrymildred Senior Member

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    Right. Now that it's reset for me, I'll never need to reset it again. And if I ever sell it, I can point out the overall MPG to the buyer and tell them, "Check that out!" :LOL:

    My wife sometimes drives my car, but only for short errands in EV. She's great about only driving when she's in the driver's seat.
     
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  9. FuelMiser

    FuelMiser Senior Member

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    This is a little misleading, I believe. It's not the "miles you have on the car", but the miles driven since you last Reset the Avg MPG. If you reset the Avg MPG with the Trip button after each fill-up, it is the same as resetting with Trip A or Trip B showing--you will accumulate the Avg MPG for that tank of fuel.
     
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  10. jerrymildred

    jerrymildred Senior Member

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    Exactly. There's really no reason to reset the MPG for the entire car's history unless you bought it used like I did and want to track your own history without influence from the previous owner.
     
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  11. Mambo Dave

    Mambo Dave Active Member

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    The thing I'm curious about is the engine RPM. I wonder if there is a way to see it while I'm driving?
     
  12. alanclarkeau

    alanclarkeau Senior Member

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    Probably you could bet it on a digital readout (ScanGauge or similar) - but it's of little use - or even less.

    I can't remember where I read that they are just all over the place - might have been on a LEXUS CT200h. Worse than an early CVT. It has been discussed on PriusChat before:

    How come our cars don't come with a tachometer | PriusChat

    ... is one thread.

    If you had one, it would tell you when the ICE is running - but there is no control you have, as the CPU controls MG2 and MG1, which in turn control the ICE. So it would just flap around like a hyperactive puppy.
     
    #12 alanclarkeau, Aug 6, 2020
    Last edited: Aug 6, 2020
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  13. Mambo Dave

    Mambo Dave Active Member

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    That's quite interesting.

    I'm more curious as there are times when I can hear the RPM being really low for the 80 MPH + I am traveling (that would be with a tail wind), and I'm just curious as to how low the RPM goes while still helping move the car at those speeds.

    I bet I'd drive even more conscientiously to try to keep the 1.8L engine's RPM lower if I could see it.
     
  14. Salamander_King

    Salamander_King Senior Member

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    Many OBDII apps shows RPM. It maybe cheaper than Scan Gauge II.
     
  15. alanclarkeau

    alanclarkeau Senior Member

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    Don't forget that RPM doesn't correlate to l/100km, though. Particularly slogging at low RPM when Max torque might be 4000 RPM (or higher). At the top of the Fuel Crisis in the '70s, people would put Vacuum Gauges on their engines, which were a better indication of fuel use. Haven't seen one of them for decades now - and with CPUs largely taking control, and more-so quite cleverly on a PRIUS, I don't think they'd be much use.

    This display on your HUD is probably the best indicator of how best to drive economically:

    upload_2020-8-7_10-24-44.png
     
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  16. Mambo Dave

    Mambo Dave Active Member

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    I remember those vacuum gauges.
     
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  17. lawrencenewman

    lawrencenewman New Member

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    First, press the "Info" button on the steering wheel until you see the MPG screen. Next, press and hold the "Info" button for a few seconds until the average MPG number starts flashing. Then, release the button and press it again to reset the average MPG. Now, the display should show the average MPG based on your driving in the past 4+ weeks.
     
  18. jerrymildred

    jerrymildred Senior Member

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    Not on a gen 4.
     
  19. sylvaing

    sylvaing Active Member

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    Four years ago old reply but pertinent to others looking for the same information.

    Hybrid Assistant will can show in real time, among many other things, the engine RPM (and mode), its output power and the MG1/2 power given/taken to/from the battery and net load on the battery.

    Screenshot_20240531-070403.png