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Discussion Starter · #1 ·
As it is elsewhere, it is very cold in Toronto this week. The ICE on my 2015 has run every day for long periods of time over the week. I have burned at least 3 liters and gone over 30km with the ICE running.

So why did Maintenance Mode execute this morning? What was the purpose of the 10 minute MM run given all the exercise the ICE had this past week due to ERDTLT?
 

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Believe it or not, ERDTT does NOT reduce the need for Maintenance Mode Cycles...(experiencing the same events in Vermont since 2013)...:)
 

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Are you sure it was Maintenance Mode?
 

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ERDTT never gets engine to proper operating temp, so EMM is still required if you didn't run the engine "for real" in the last 6 weeks.
 

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ERDTT doesn't get the engine fully warmed up, only gets it warm enough to provide cabin heat. The engine still needs to run maintenance mode to get nice and hot. Every now and then you could put it in hold mode in the winter for your commute and avoid the EMM.

I don't have hold in my 2012, but since my range is so limited in these temps I have no issue needing EMM. Otherwise I put it in mountain mode for a few minutes when it is low to get nice and hot.
 

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Here is a trick to minimize gas usage on ERDTT:

Put the heating to "Max"
Set the temperature to "28C"
Set the fan speed to you liking
Optional: Set ventilation to "Windshield Max"

The Max 28C will force the use of the electric heating coil in the engine Prestone. In most case it will be enough to keep the prestone temp above 60C all the time. Only time when it will drop below 52C is if it is really cold and you have the fan running above the half mark.

Try it, you will be pleasantly surprised as to how much fuel it saves.
 

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Are you sure it was Engine Maintenance Mode (EMM) and not Fuel Maintenance Mode (FMM)? EMM should use only ~0.03 gallons of gas and run once every six weeks if the ICE is not otherwise used to propel the vehicle. Fuel Maintenance Mode starts when the "average age" of the gas in the tank is ~12 months old, and once it starts, the car uses the ICE. You can’t run again on battery power until you add fresh gas, or run the ICE until the gas is gone, and then add fresh gas. How long has it been since you last added some gas?
 

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One of the major goals of EMM is to drive all the moisture out of the engine oil. For this to happen, the oil temperature has to get up near the boiling point of water. ERDTT doesn't get it that warm, which is why it doesn't reset the EMM counter.

If you're hitting ERDTT routinely but not using the engine otherwise, it might not be a bad idea to use Hold mode occasionally as one poster suggested. That will prevent you from getting EMM (assuming the car had time to fully warm the engine during that run.)
 

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If it was FMM, wouldn't the ICE run until the fuel was taken care of? OP?
 

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Discussion Starter · #10 ·
It was EMM not FMM.
The gas was pretty fresh.
I will try the trick of setting the heat to 28C as described above by bmaltais.
 

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EMM should use only ~0.03 gallons of gas
It will use 3-5x more gas in the winter because of the extreme cold sapping the heat.
Also runs much longer because it's harder to maintain the temp high enough, for long enough.
Many people also would not turn the heater off, which is also drawing heat from the engine, prolonging it further.
And if they don't let it complete to 100%, starts again on next run, etc.
If it triggers and you're already at your destination, best to put it in park, turn off the HVAC and press the pedal down to accelerate the process and let it finish before shutting off the car.
 

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It will use 3-5x more gas in the winter because of the extreme cold sapping the heat.
Also runs much longer because it's harder to maintain the temp high enough, for long enough.
Many people also would not turn the heater off, which is also drawing heat from the engine, prolonging it further.
And if they don't let it complete to 100%, starts again on next run, etc.
If it triggers and you're already at your destination, best to put it in park, turn off the HVAC and press the pedal down to accelerate the process and let it finish before shutting off the car.
Thanks for the feedback. Last night the midnight outdoor temperature in my neighborhood in Portland, Oregon, when the New Year arrived was 40 degrees F (4 C), which might indicate I haven’t had much experience with ERDTT in the 5.5+ years I’ve been driving my 2012 Volt, nor with experiencing EMM in that level of cold weather.

I take long vacation drives once a year or so, but hover around 99+% ev with local driving, leaving nearly year-length gaps between long trips (endured my third FMM last October). I find it convenient to avoid adding minuscule gas mile numbers to my records by sitting in the driveway until the EMM has concluded. This also provides me with a rare opportunity to "rev" the engine by stepping on the accelerator.

One oddity I do notice is that the energy usage display usually stops increasing the "Gas Used" quantity about midway or so through the EMM, and eventually concludes some minutes later with no more gas being used. This puzzled me until I read a comment in this forum fairly recently that seemed to indicate this could be proper behavior. The smaller motor is first clutched to and then serves as a starter motor for the gas engine. The EMM is intended to make sure the engine is properly lubricated, so, I suppose, once the fluids attain their proper running temperatures, "engine lubrication maintenance" could be handled just as well by having the motor turn the engine’s internal parts instead of burning additional gas to accomplish the same goal... Is this indeed what happens?
 

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It was EMM not FMM.
The gas was pretty fresh.
I will try the trick of setting the heat to 28C as described above by bmaltais.
That'll just help reduce ERDTT. It works, I use it all the time, but I don't think it'll help the issue with the ECM deciding it still needs an EMM occasionally in the conditions we are having right now as the engine WILL still run in ERDTT, especially at startup.

Although I know how you feel about unnecessary use of gas...sometimes you have to let it do it's thing in the interest of keeping the engine longevity intact - you don't want your engine sitting with a bunch of water in the oil.

If you want to completely eliminate ERDTT (and the EMM's that will eventually come with it after enough of them) you may want to look into the defeat solutions out there.
 

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Thanks for the feedback. Last night the midnight outdoor temperature in my neighborhood in Portland, Oregon, when the New Year arrived was 40 degrees F (4 C), which might indicate I haven’t had much experience with ERDTT in the 5.5+ years I’ve been driving my 2012 Volt, nor with experiencing EMM in that level of cold weather.

I take long vacation drives once a year or so, but hover around 99+% ev with local driving, leaving nearly year-length gaps between long trips (endured my third FMM last October). I find it convenient to avoid adding minuscule gas mile numbers to my records by sitting in the driveway until the EMM has concluded. This also provides me with a rare opportunity to "rev" the engine by stepping on the accelerator.

One oddity I do notice is that the energy usage display usually stops increasing the "Gas Used" quantity about midway or so through the EMM, and eventually concludes some minutes later with no more gas being used. This puzzled me until I read a comment in this forum fairly recently that seemed to indicate this could be proper behavior. The smaller motor is first clutched to and then serves as a starter motor for the gas engine. The EMM is intended to make sure the engine is properly lubricated, so, I suppose, once the fluids attain their proper running temperatures, "engine lubrication maintenance" could be handled just as well by having the motor turn the engine’s internal parts instead of burning additional gas to accomplish the same goal... Is this indeed what happens?
It was -25C (-13F) on NYE this year.
Perhaps that might further what I mention re: cold sapping the heat of the engine that it's trying to keep up ;)

As for the last part, that's correct. I've logged a few with OBD and it only uses fuel for the initial warmup period (which takes a whole lot more when the engine is -25 than when it's +25) then the rest of the period is the electric motor spinning the engine to keep things moving and warm, and fuel use drops to basically 0. You can actually hear the pitch change when this happens, if you're listening carefully.
The net result of EMM is electricity used, not generated (as one would expect if the engine was running itself the entire time).
 
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