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My intial fill up for my 2016 Gen 2 was on 10/20/15. The Fuel Maintenance Mode then started on 4/20/16 with about 3.5 gallons left. I filled the tank back up with 5 gallons thinking it should stop this mode. It is still running. Will it continue with this mode until it uses 3.5 gallons? My commute is 38 miles round trip, so I am normally using no gas most of the time. What should be done to prolong this mode from starting in the future? Thanks.
 

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From the manual "The engine will run until enough fresh fuel is added to bring the average fuel age into an acceptable range." Apparently you are not at the acceptable range.

Since you do not use much fuel, I would recommend never fill the tank. Once your get close to empty only add 3 gallons or so. Then the FMM may not come on at all or will come on for a shorter period of time.
 

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My intial fill up for my 2016 Gen 2 was on 10/20/15. The Fuel Maintenance Mode then started on 4/20/16 with about 3.5 gallons left. I filled the tank back up with 5 gallons thinking it should stop this mode. It is still running. Will it continue with this mode until it uses 3.5 gallons? My commute is 38 miles round trip, so I am normally using no gas most of the time. What should be done to prolong this mode from starting in the future? Thanks.
Wait!
How did you get fuel that is 1 year old into a car that is only 6 months old?
You may need a dealer visit. Seems like something is wrong here.
 

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Wait!
How did you get fuel that is 1 year old into a car that is only 6 months old?
You may need a dealer visit. Seems like something is wrong here.
Good point. Per the manual:

"FMM tracks average fuel age. Old fuel can cause engine problems.
If low engine usage causes average fuel age to exceed approximately
one year
, FMM will run the engine to use up the old fuel.
The engine will
run until enough fresh fuel is added to bring the average fuel age into an
acceptable range. Allowing more old fuel to be used up by FMM and
adding a larger amount of fresh fuel will maximize the length of time
before another fuel maintenance mode is needed."
 

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This is the second mention of this "false" FMM problem in recent days (adding sufficient amounts of new gas should end the FMM). Look at the Fuel Maintenance Mode Gone Wild thread referenced at the bottom of the page. Has your 2016 recently received an update which that thread's OP called an engine misfire recall? It appears the dealer can do something to "reset" the FMM timer. I wouldn’t want such a procedure to become a common method of ending a normal FMM.
 

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Good point. Per the manual:

"FMM tracks average fuel age. Old fuel can cause engine problems. If low engine usage causes average fuel age to exceed approximately one year, FMM will run the engine to use up the old fuel. The engine will run until enough fresh fuel is added to bring the average fuel age into an acceptable range. Allowing more old fuel to be used up by FMM and adding a larger amount of fresh fuel will maximize the length of time before another fuel maintenance mode is needed."
And that is what happened this morning as I am a couple weeks away from the one-year mark, but the car was assembled in the last couple days of Sep 2015 so I guess it was time for the first FMM as was noted on the dash when I started this morning.

It was strange not using much of any HVB during the drive, but the MPG of the ICE did very well.

 

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Crap. My car came with a full tank from from the dealer and I've used less than a litre. How long will my FMM last?
 

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Crap. My car came with a full tank from from the dealer and I've used less than a litre. How long will my FMM last?
I don't know, this morning was the first time it's come on -- I have 36k miles and still had 3/4 tank as I only had 3 short trips that involved ICE in the first few weeks I owned it, but nothing but EMM (and ERDTT x3) since last November.
 

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Crap. My car came with a full tank from from the dealer and I've used less than a litre. How long will my FMM last?
It will want to burn ALL of the old fuel. You can add new fuel to the tank and cause the average age to be less than 1 year which should stop the FFM. I would suggest letting it burn almost all the fuel then just add about 3 gallons for emergency/cold weather use (that's about one third of a tank for you Canadians).
 

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And that is what happened this morning as I am a couple weeks away from the one-year mark, but the car was assembled in the last couple days of Sep 2015 so I guess it was time for the first FMM as was noted on the dash when I started this morning.

It was strange not using much of any HVB during the drive, but the MPG of the ICE did very well.

Yes, 53.2 mpg just on gas is better than 98% of all cars out there will get, except for perhaps the Prius. We never worry about FMM or EMM as we take at least once or twice a month a trip to Portland Oregon in our 2016 Volt. Infact it is cheaper to use the Volt than our 2010 Prius for those trips even when you consider the cost of electric with the Volt.
 

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It will want to burn ALL of the old fuel. You can add new fuel to the tank and cause the average age to be less than 1 year which should stop the FFM. I would suggest letting it burn almost all the fuel then just add about 3 gallons for emergency/cold weather use (that's about one third of a tank for you Canadians).
Might as well abuse the cabin heating during winter. At least the fuel will be used for something useful.

Am I to understand FMM runs once a year only?
 

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Might as well abuse the cabin heating during winter. At least the fuel will be used for something useful.

Am I to understand FMM runs once a year only?
Only if you burn off all of the old gas. If you are at half a tank of fuel when FMM starts, you can fill the tank, but that will make the average age of the fuel now 6 months and FMM will return is 6 months instead of 12.
 

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Only if you burn off all of the old gas. If you are at half a tank of fuel when FMM starts, you can fill the tank, but that will make the average age of the fuel now 6 months and FMM will return is 6 months instead of 12.
Look on the bright side. The full tank serves as ballast to lower the rotational inertia of the car and keep it more neutral in corners :)
 

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It will want to burn ALL of the old fuel.
OK I tested your claim and you were correct. I was below the low fuel warning with probably about 20 miles of fuel left when I started the last trip, wondered if starting a trip in that status would keep the FMM from continuing since the fuel level was already low - nope, you are right it wanted to burn ALL of it and did.

There was no engine sputtering as it used the last of the fuel, it just flat out stopped while driving and the below two messages were shown. I started the FMM earlier on Wednesday with 3/4 tank from the dealer, when it entered FMM it hardly used the HVB at all (2.4kWh), as shown on the last screenshot. Driving on ICE sucked when the HVB was sitting there almost fully charged, oh well.

 

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Wow, what great economy ... My lifetime MPGe is only 104 and my best ICE MPG is around 44 MPG. Then again, I live in South Florida and I'm always running my A/C. Also, part of my daily commute is highway and I can go around 70 MPH.

Then again, you really can't complain about 104 MPGe!

I run mostly on battery because I can charge my car while at work. The last time I purchased gas was last year right before Hurricane Irma threatened Florida. I'm in FMM right now with about 100 miles of distance estimated on fuel. I should burn all of that fuel in a day or so. I'll fill up half way at that point.
 
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