[bwilson4web]

Tonight I found that running out of gas completely removes all traction battery power. There is no motive power to get to a 'safe place' to refill. I was able to coast to a parking lot but basicly:

• power steering icon - this is the only warning light, IMHO, inadequate
• all power indications 'off' - as if the car had been shifted into "N"
• shifting to "N", stays in "N" and does not return to "D"

I can buy a new traction battery and have no problem with being put in "EV" mode. But the car would not shift into "D", much less "EV." Compared to the NHW20 and NHW11, this means a valuable safety feature has been lost.


Trying to run out of gas, on flash, it went:

• 122.1 mile
• 56.6 MPG
• 2.156 gallons, 1.6 gallons in handbook

The only indication I got of a problem was "electric steering error" icon flashed up. No sure what it was, I pulled over and put my spare gallon in. The error indication cleared and I was off to fill-up.

Second running out of gas on flash, it went:

• 132.6 miles
• 60.8 MPG
• 2.18 gallons

Absent a return to a 'limp to the side of the road mode,' I can no long support running out of gas as "no big deal." In fact, I believe the former behavior of the NHW20 and NHW11 to be superior to this "coast to a stop NOW!" behavior.

Bob Wilson

[centrider]

Wow!

What was Toyota thinking?

[geodosch]

From your screenshot of the dash, it looks like there was a very low SOC, which may explain why it would not go into EV mode. It would be interesting to know if you could have used EV mode with a higher SOC. I wouldn't expect the software that determines whether it's OK to switch to EV to take into account having run out of fuel, and over-ride the normal battery safety features. I know you made the statement "I can buy a new traction battery...", but something tells me that the vast majority of owners who were told they need to spend $$$$K to replace their traction battery because they ran out of gas, and continued to drive on a low battery, wouldn't be happily accepting that explanation.

Personally, I don't see this as a major issue. In both cases you were able to drive well over 100 miles after getting the dire warning, so if someone did accidentally run out of fuel under these circumstances, my feeling would be that they got what they deserved. (and I realize there are places where there are more than 100 miles between exits, but if you started on one of those stretches with the fuel gauge near 'E', you really can't blame the car.)

[bwilson4web]

geodosch said:

From your screenshot of the dash, it looks like there was a very low SOC, which may explain why it would not go into EV mode. . . .

I'm on a tank of Shell 87, E10, and it makes sense, now that I know the mount of fuel "on flash," to do one more fuel exhaustion test but at a higher velocity with a higher state of charge.

Bob Wilson

[bwilson4web]

I have good news and bad news:

GOOD NEWS!

The Prius automatically converts to EV mode.

BAD NEWS!

There is no "check engine" light or other indication that the gas is actually out! This of course begs another question ... is the "check engine" light working?

I also ran another 2.16 gallons on flash. Also, the actual tank capacity appears to be 12.09 gallons.

I pulled off the interstate and took an interchange to return. I knew it should run out any minute but it wasn't until the acceleration down the ramp was 'sedate' that I realized the gas engine was not coming on. There was no error code.

So I continued on EV mode down the ramp and on to the shoulder and then 100 yards further and well off the shoulder. I added my spare, 1 gallon, and drove to my local Shell station to fill up with 87, E10.

WORKAROUND (UNTESTED!)

When running on flash an the tank is about to run dry, put the display in energy flow mode. As long as you see engine lines, it is running. But if the engine stops and the battery is supplying power, then you are a limited range, EV. It is time to park 'RIGHT NOW'.

It may take a couple of weeks before I can test the workaround.

Bob Wilson

[bwilson4web]

I understand that Toyota USA believes this is how they want the car to behave when it actually runs out of gas. I still believe it is better to let the operator know the engine will no longer run for any reason, including running out of gas. Fortunately, we can each proceed according to our beliefs without 'bumping ugly.'

As someone had pointed out in another forum, there is a desire for an indication of when the engine is running. That happens to dovetail with another project I've been planning and it is easy enough to incorporate an independent "check engine light" indicator. But what to do in the meanwhile?

For those who may be curious, this is the latest addition to our 2010 Prius kit:

(NOTE: I saw the same 1 gallon spare can at WalMart.) This is the "Northern Tool + Equipment" part 179057, "Enviro-flow 1-ga. Gas Can P" that fits nicely in the left-hand storage area. There is an interlock on the valve that requires two-handed operation to open and I know it will handle high temperatures. With the carpet cover, it will avoid direct sunlight and should handle even Alabama summers. Yes, I researched and ordered the part a week ago when I realized what is happening and the time it would take to effect a permanent fix.

I was hoping this would be a temporary workaround until a better solution came along. No problem, no fault, no foul. Having an answer maps out my course and really, this is not a problem for the Wilson family.

Thanks,
Bob Wilson

[JayC]

Interesting, I buy gas when there is 1 pip and/or the miles to empty shows 60mi or less. Why run a car to empty? Interestingly, I have only been able to feed the car a max of 9 gallons to fill it up so there must be a "reserve" of a gallon after that last pip goes out.

Again, Why run a car to empty?

Jay

[bwilson4web]

Hi,

My original requirement was to do gasoline studies. When I learned the NHW11 would give me a lot of warning and revert to EV mode, it was a simple and safe process. But my wife's ZVW30 gives no warning and simply runs until the traction battery has lost too much charge. Then it puts up an "electric steering fault" warning.

I've never measured the miles and consumption from 'last pip' to 'blinking' but when it starts 'blinking', there is about 2.1 gallons of gas left. I've run out of fuel three times and the 2.1 gallons appears to be pretty firm. So I can believe 9 gallons added with 2.9 gallons remaining in the tank (that is a 2010 Prius, right?)

Bob Wilson

[geodosch]

bwilson4web said:

/...]When I learned the NHW11 would give me a lot of warning and revert to EV mode, it was a simple and safe process. But my wife's ZVW30 gives no warning and simply runs until the traction battery has lost too much charge. Then it puts up an "electric steering fault" warning.

I've never measured the miles and consumption from 'last pip' to 'blinking' but when it starts 'blinking', there is about 2.1 gallons of gas left.

Bob,

You say the Gen3 'gives no warning', but then you say from 'blinking' to empty is 2.1 gallons, which at 50 MPG (very conservative) gives you over 100 miles from 'blinking' to out. So I don't understand how that translates to "No Warning". As I pointed out in an earlier post, 100 miles should be plenty of distance to find a filling station.

Is 100 miles too little warning for your liking, or is there something that I'm completely missing here? I've had cars that would get about 250 miles on a tank. So being able to drive 100 miles after you're past 'empty' just doesn't seem like it would be a big issue for most people.

[bwilson4web]

I want the "Check engine" light to come on when the engine has no more gas. I can handle the remaining mile or so of range if I know that I'm now driving an electric-only Prius.

Bob Wilson