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Discussion Starter #1 (Edited)
I have notified Onstar / Volt Advisor / Chevrolet Support regarding the following 2013 Hold button issue. They are working with engineering on it and will get back to me.

When ever I switch from normal to hold mode to force the engine on (normally up steep hills) and switch back to normal mode, the energy usage screen on the center console does not reset to battery power once the engine turns off.

So for example, I have driven 20 miles on battery and have 18 miles remaining. I have a steep 1 mile grade to go up so I change to hold mode - the engine turns on (I can hear it and the blue gas pump replaces the accelerate / de--accellerate efficiency ball and the battey gauge on the left grays out. I drive 1.1 miles up the hill. The energy usage display (pie chart) now shows 20 miles battery / 1.1 miles gas. The gas use is 0.07 gallons. I then switch from hold mode to normal and the blue gas pump disappears and the accelerate / de-accellerate efficiency ball reappears and the battery reappears with around 18 miles. I drive another 10 miles and all 10 miles are pegged as gas miles even though I'm 100% on battery. At the end of the trip, the efficency guage will show 20 miles on battery and 10.1 on gas when it should read, 30 miles on battery and 1.1 miles on gas. By the way, the gas used still says 0.07 gallons and battery range has 8 miles left.

This is purely a stat problem and not an operational problem, the hold mode does work as intended. Just the program needs to be fixed to show the stats correctly. Anyone else want to try the hold mode on your 2013 and report back.
 

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I noticed this in Mountain Mode when you switch to MM after switching from CD to CS mode. Then after a good 20 minutes, switch to normal mode where the battery is running the car, the gas-mode stays in place. A lot of folks have have seen that and say that if you stop the car, turn it off, turn it on - it will go back to CD-mode (EV-mode). Basically, they somehow relate "miles following running the engine" as always with CS-mode (gas engine) so it messes up the perceived CD-mode miles.
 

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Does the same thing on mountain mode as the battery could have been recharged from the ICE, not held as the new hold mode does. sounds like the didn't update the tally feature as hold doesn't add energy to the battery
 

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I have seen this behavior in MM as well. I agree it's a minor bug. But I think GM should make the effort to fix it.

Considering that 2011, 2012 and 2013 Volts all have this issue with MM... I am not confident that GM is going to take the time and effort required to fix it.

Or... Perhaps they don't consider it a bug.
 

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In terms of software, my programming history says this is an "if then else statement" issue and it could easily be fixed. Maybe in the next release if enough people complain about it.
 

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In terms of software, my programming history says this is an "if then else statement" issue and it could easily be fixed. Maybe in the next release if enough people complain about it.
You programming experience pre-dates multi-processor, object oriented programming. ;-)
 

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When ever I switch from normal to hold mode to force the engine on (normally up steep hills) and switch back to normal mode, the energy usage screen on the center console does not reset to battery power once the engine turns off.

So for example, I have driven 20 miles on battery and have 18 miles remaining. I have a steep 1 mile grade to go up so I change to hold mode - the engine turns on (I can hear it and the blue gas pump replaces the accelerate / de--accellerate efficiency ball and the battey gauge on the left grays out. I drive 1.1 miles up the hill. The energy usage display (pie chart) now shows 20 miles battery / 1.1 miles gas. The gas use is 0.07 gallons.
Are you just testing Hold mode here? Otherwise, why bother to engage it for a 1 mile hill???
 

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Are you just testing Hold mode here? Otherwise, why bother to engage it for a 1 mile hill???
Agreed, this makes zero sense to me! I don't think the generator completes its warmup cycle and starts generating much electricity within that short of a period of time; wouldn't using EV up the hill be far more efficient?

Maybe I'm not understanding the scenario correctly.

-Drew
 

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I have used hold mode on my Volt to demonstrate how loud the engine is and how the Volt operates in gas mode (show that power and response is no different). After I switch back to normal or sport the miles are recorded as EV miles. So I don't seem to have the glitch you appear to have.
 

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I haven't had any issue with hold mode. I've been using it for the middle of my commute and it tallies the stats correctly.

The only issue I've seen so far is that my service parking brake warning has come on a few times. Going to take it to the dealer if it continues.
 

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I've had the same issue in MM. When we took our road trip a few weeks back, I had MM engaged the entire time. When we would stop in a town to eat, I would go back to Normal mode as soon as I exited the freeway. The car would shut the engine off and run off battery, but the display would continue to show miles as gas miles and not electric miles. However, after eating and having the car shut off for 30-40 minutes when it was restarted, it would add miles to the electric miles total again.
 

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Having done a lot of MM gaming, I can tell you that whether or not you immediately re-enter CD mode when exiting MM depends on a couple things (including how you entered MM and how much SOC you lose while climbing).

First if you enter MM from CS mode after already depleting your battery then you will never go back to CD mode (even if you stay in MM long enough to fully rebuild the extra buffer). I don't think this is a bug because in this case any new buffer is created using gas and should count as gas miles.

Second if you enter MM from CD mode with only a few miles left of electric range then again you will not return to CD mode upon exiting MM. This applies even if you switch to MM and immediately switch back. The lowest estimated EV range I've been able to go down and switch to MM and then successfully switch back to CD mode has been 4 miles. That only worked when switching just after EER dropped from 5 miles to 4. I've also waited a bit longer and switched to MM with 4 miles of EER but failed to switch back to CD. So the SOC threshold is somewhere around there. Maybe a hysteresis effect?

Third, even if you enter MM from CD mode with a high SOC (more than 14 miles of EER), you still may not go back to CD mode. It depends on how aggressive and how long the climb is. As you're climbing you're depleting the SOC even with the ICE on max output. This is the point of having the extra MM buffer in the first place. But it is very possible to deplete the SOC down to below that "4 mile EER" SOC threshold I mentioned. If you do this, then even though you started MM with a full extra 14 mile buffer you will not re-enter CD mode.

I ran into this third scenario a few times when commuting over the Santa Cruz mountains on colder days. Most of the time I could do the climb engaging MM above 14 miles EER and then exit MM at the summit and re-enter CD mode with about 5-6 miles of EER (so I lost about 9 miles worth of SOC while climbing). On some colder days however, I could get the summit and have depleted the SOC low enough that the Volt would not re-enter CD mode and stayed in CS mode. Presumably I burned up the entire 14 mile buffer on the climb.

FWIW I don't think any of these scenarios are "bugs" or "glitches". In the first scenario any new "electric" miles are from gas generation. In the 2nd scenario, you may technically have lost a few miles that should have counted as EV in your stats. In the 3rd scenario, it's more complicated because what you've actually done is driven simultaneously on gas and electric so the miles should really be divided proportionately assuming the Volt had a way to do this. But since technically you were using gas at that time it counts as 100% gas miles. And since you fully burned up your remaing electric buffer during that time, then technically you have 0 available EV miles from that point on in your trip.

After thinking about it, I think GM made the right decision(s). If anything I would say the real bug is being able to power the car off and then back on and tricking it back into CD mode where you can inflate the EV stats with gas generated miles.
 

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First, I've shared Joule Thief's experiences, so I think he's pretty much right on with everything. My only complaint, and this is a broader complaint, is that the Volt doesn't display the battery charge while in MM. Even if it shows gasoline as the primary source, it would be nice if it accounted for how much of a charge is in the battery. I understand that they might not want to list it as range, per se, but it would be nice to see the actual capacity.

On a side note, even if the default is "range," I really would like an option to switch to a capacity (both kWh and gallons) readout in the display.
 

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I may have jinxed myself. I think mine did do this on the way home yesterday. I came out of hold mode and it kept counting gas miles. I didn't try and troubleshoot it too much, I just switched back to hold mode because I was having a particularly good EV day and didn't want to screw up my stats. I would've hit 47 on a 95 degree day. I'm looking forward to the fall when the temperature is more mild.

I haven't had any issue with hold mode. I've been using it for the middle of my commute and it tallies the stats correctly.

The only issue I've seen so far is that my service parking brake warning has come on a few times. Going to take it to the dealer if it continues.
 

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I did a little more playing around with hold mode today, and it appears that it accounts for any charge accumulated from running the gas engine. The car added a mile to the EV range while in hold mode, then when I came out of hold, it continued to add to the gas miles until the EV range returned to its pre-hold value. Pretty accurate accounting, I guess.
 

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In terms of software, my programming history says this is an "if then else statement" issue and it could easily be fixed. Maybe in the next release if enough people complain about it.
As a software engineer, I cringe when folks say that something should be "easy".
This type of Boolean statement (your "if...then" statement) logic adds to the level of cyclomatic complexity in which a higher level has a propensity to introduce anomalies and defects (i.e. bugs), whether subtle or not, and also makes the quality assurance process more complex.
 

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My 2013 has the Hold Mode Gas Mileage calculation issue. I switch from Hold to Normal and the counter will run for another 2-3 miles normally... it's quite bizarre because the fuel consumption stops completely.
 

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Opening this up again as I think, this is really an issue that bugs me. I have a 65 mile commute, but in the morning, it is usually a breeze, while coming back is stop-and-go. So I use ICE when I get on the freeway (after about 4 miles) and then shut it off when I encounter traffic. But even when I get rid of the hold mode, the counter keep counting gas miles. This is annoying and definitely screws my stats up..

brandonee, have you found a fix? Could this be fixed in a software update?


I did a little more playing around with hold mode today, and it appears that it accounts for any charge accumulated from running the gas engine. The car added a mile to the EV range while in hold mode, then when I came out of hold, it continued to add to the gas miles until the EV range returned to its pre-hold value. Pretty accurate accounting, I guess.
 

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In my 2013, exiting Hold mode as I do at least twice every weekday, the thing about it counting another gas mile or 2, and how much battery range/how many estimate bars are restored, tends to vary. I think it depends on what part of the "series hybrid cycle" it's in (also what strategy it was using) when I push the button to exit Hold mode.

I think it depends on how much of a charge "buffer" it had designated and built up in the battery, at the moment I exited Hold mode, and as I said I think that depends on the strategy it was using (highway driving strategy above 63mph with engine constantly on? or "series hybrid" strategy, cycling the ICE on and off?) and if cycling, what part of the cycle it was in, how much the buffer had been filled.

Also I notice during Hold mode that the battery range estimate changes too; sometimes the top "bar", above the red "hold line", turns green; other times it turns grey again, presumably as the "series hybrid" cycle goes along. I'm guessing that top "bar" represents this "buffer" that Hold mode has reserved in the battery, for filling and depleting repeatedly in the series hybrid cycle.
 
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