MFD indicates 0 mpg at times! What's going on?

[Wildkow]

Can someone tell me why my MFD is doing this?

Background; trip to San Luis Obispo to watch the Mustangs Baseball team play. A friend and I are on the freeway, the ICE is nice and warm and the temp is 75F and we just filled the tank. I’m letting a friend drive (he wants’ one bad now) and he’s alternating between cruise/non-cruise mode. I look down after explaining the attributes of the Prius to him and ACK! WTH! Is going on?!? Zero mpg for the last ten minutes and crappy mileage before that?!?! Yet the overall mileage indicates 43 mpg.

After the game, Mustangs won, we drive through town and got right on the highway back to Fresno and it happens again! Ten minutes gets us through town to the highway, 101 north, and we get 55-90 mpg, my friend is getting pretty good huh? BTW gas in SLO was $3.999/gal for regular, glad I had the Prius? The next fifteen minutes gets us to the bottom of the grade going over Cuesta Pass, its not flat but it’s not that much of a grade change and what do we get? Zero to ten mpg again, temp was 91F!

I had this problem many many months ago, still under warranty then BTW , and the dealer said nothing wrong and no error codes. Then it went away until a couple days ago. This is just weird any thoughts?


Wildkow

[Sheepdog]

hmmm. I think those error codes might not be as OK as the dealer said?

[derkraut]

Originally Posted by Sheepdog

hmmm. I think those error codes might not be as OK as the dealer said?

I agree. There's something amiss. I would take the car to the dealer ASAP, explain what you encountered, and have him run another code readout.

[nmrickie]

I've noticed the same thing every once in a while. In fact, it happened today shortly after I filled up with gas.

I did notice that the average MPG was not affected -- just a couple of bars that indicated 0 or very low MPG. Sometimes it will show several regeneration symbols "floating" by themselves in the black area.

I did a scan and there were no error codes.

[Rokeby]

Newbie here, hardly an expert.

I've noted in numerous threads that when weird, unexplainable, seemingly random things like this occur, its frequently the 12V battery making a cry for help just before it dies. Well, not really, it's the CPUs getting less than min electricty.

You might consider having it looked at/tested.

FWIW

[qbee42]

The only time I see zero bars like that is when I'm standing still. Obviously you get zero mpg if you are not moving, but that doesn't sound like your situation. Do you have any sort of speed sensor defeat installed to allow running the MFD when moving? If you do, I'd check that, otherwise something is fishy.

Tom

[diamondlarry]

It seems that I've heard somewhere here on Priuchat that 0 mpg bars are an indication of standing still or no fuel being burned for that period?

[nmrickie]

This happens to me in situations where it definately should not be showing zero -- just normal driving.

[Sheepdog]

I certainly hope Japan didnt fall for that deal Bill Gates had for programming!

[miscrms]

This may or may not be what is happening here, but I believe that this can occur under normal circumstances. I think its an artifact of the way that the instantaneous mpg is calculated. As I recall, if the ICE doesn't start during a 5 minute period, then it will show 0 mpg even if you have been moving. This can happen even at freeway speeds going down a long down hill. In crawling traffic tends to be another. It sounded like these might have been the two circumstances you encountered, but I'm not sure.

Here are a few related threads:
Black Bars in Consumption Screen
"Missing" bar in Consumption screen
Explain this for me
Interesting (?) consumption screen bug

Rob