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OK, who knows...

1. Which sensor decides that it's 25 degrees or below and starts the engine?

2. Where's it located?

3. Is it just coincidence that as the display drops down and shows 25 degrees, the engine starts.

Tired of having the motor start just to park the thing with a warm engine. Yeah, I know why it starts, I just don't think it needs to for my 15 mile drive and the temp just below 25.
 

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The engine won't come on unless the water temp is also below a certain temp as well, so it's 2 things....

MrEnergyCzar
I dont believe the coolant temperature has anything to do with the first engine start of a cycle, its for the subsequent ones that it is used to gauge when to run a second, third etc. You can pre-condition in a garage and warm everything up but as soon as the temp hits the magic number it switches on, sometimes less than a min after leaving the garage after pre-conditioning.

I guess if you can fool the engine into not starting the first time then you wont have to worry about the coolant. Now where the sensor is located, no idea.
 

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See page 4 here: http://www.sandyblogs.com/techlink/Jan 2011 Techlink F.pdf

"At ambient temperatures of approximately 25° F (–4° C) or below, the ICE will operate to assist in warming the coolant used to warm the vehicle’s cabin. After the coolant temperature reaches approximately 150° F (65° C), the ICE will turn off and remain off (as long as the battery state of charge is sufficient) until the engine coolant temperature drops to approximately 104° F (40° C), at which time the ICE will restart. This function will continue as long as the ambient temperature is approximately 25° F (–4° C) or less while driving. After the ambient temperature rises above approximately 25° F (–4° C), the vehicle will resume normal electric operation (as long as the battery state of charge is sufficient). This is normal operation and no repairs should be made to correct this condition."

So, yes, engine coolant temp does matter. But if the car has been sitting off for awhile, the coolant temp won't be above 104F*, so the engine will kick on every time if the ambient temp is <26F.

*I've seen several people on this forum who use a DashDAQ to monitor actual engine coolant temperatures, and some have reported that the temperature threshold for the engine coming on is actually higher than 104F -- more like 114F or so.
 

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So, yes, engine coolant temp does matter. But if the car has been sitting off for awhile, the coolant temp won't be above 104F*, so the engine will kick on every time if the ambient temp is <26F.

*I've seen several people on this forum who use a DashDAQ to monitor actual engine coolant temperatures, and some have reported that the temperature threshold for the engine coming on is actually higher than 104F -- more like 114F or so.
AFAIK the 114F came from my testing with a ScanGuage. See this thread. As well in that thread I pointed out that when I do precond/remote_start that my ICE WT (water/coolant temp) rises. saghost can't recreate tho. I've never tried it more than twice to see how I could get it (would need to recycle/start/stop) to get around the 2 times precond limit tho.

COMFORT-setting-limiting-quot-Engine-Running-due-to-low-temperature-quot-ERDTLT
http://gm-volt.com/forum/showthread.php?11181-COMFORT-setting-limiting-quot-Engine-Running-due-to-low-temperature-quot-ERDTLT
 

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The sensor is located on the bottom passenger side of the radiator frame. It's a small sensor that changes resistance according to temperature. I believe that there should be an option to keep the car in electric mode below 25 degrees
 

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Hi all - I hear that the VERY COLD setting on the new cold weather config option will be 5-10 degrees lower than the existing COLD setting. This will offer much greater improved performance for the winter in EV mode for short trips and when preconditioning the vehicle when plugged in so the engine doesn't run. Final temp setting yet to be known.

Bad news - no software upgrade known at this time. I would suggest we write some letters to demand they add. I know that we can hack a work around but I would prefer not to do this. Pertinent addresses below.

Daniel F. Akerson , Chief Executive Officer
General Motors Corporation
105 Justice Street*
Detroit, MI, USA*
48265-0001

Micky Bly, Executive Director, Global Electrical Systems, Infotainment & Electrification
30001 Van Dyke Avenue
Warren, MI
48090-9020

Kevin Williams, President and Managing Director
GM of Canada Ltd.
1908 Colonel Sam Drive
Oshawa, Ontario
L1H 8P7
 

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You guys seem not to realize how much work GM did on this one to keep the battery life long. At cold temps, all batteries have various issues (see any chemistry text). This is in there for a very good reason, not just the help out the pretty anemic cabin heater. Just run the doggone engine, keeps it oiled and ready for when you need it. I for one, would like to be able to force it on when it's really cold, as I need the range that the electric heater destroys heating the coolant loop.

This is about the last hack I would do on this car. Ruin the battery with it and see how you do at warranty time.
There's an explicit statement about this in the coffee table book they sent us - I'm quite willing to believe it. Not too hot, not too cold, not too much or too little charge...that's why the main battery can live as long as they do. You know GM had to have some pretty compelling reasons not to use the whole charge window, right? Same motivation here.
 

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Agree with DCFusor. No problem trying to get GM to offer the mod but doing it on your own wouldn't seem to pass the cost/benefit test (easy for me to say I think the last time the temp got under 32F was the last ice age). I understand why people don't want the engine coming on but even for the 2013 MY there is still a lower temperature at which the engine is forced on, and you have to think that the temperature was set for a reason.
 

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Why do you guys want to lug around about 400# of engine block for no reason? GM put that under the hood for a couple reasons. I've got a great way to hack it- hack the engine out, and let it sit on your garage floor.

Let the engine run. It won't hurt your car. Trust me, I drove over 330 miles last week, to Chicago and back, and the engine ran just fine, the car was great, and my wallet was happy. Only 8.5 gal. of gas used.
 

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No way I want to risk my battery.. and only want a few degrees of shift. Unlike some of the other hackers here I will absolutely not hack the main connector.. I'll play at the sensor it self. If I had the "cold or very cold" options it would be moot. But if they can have it an an option then I can effectively shift the temp a bit to get the same effect. Especially a pain to have 3 engine starts when doing 6 miles of short trips.. and arrive home with 25miles of RV range.. (even using Comfort).

And hey hacking can be fun ;-)
 

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+250 Bzzzt (more or less the actual engine weight here). If people want a hack - heck, take the spark plug wires off, and leave them at home. Then see how you feel that one time you really need it - you'll be cured. Heck if you have them with you and it's raining/sleeting and you have to get drenched to keep going...that should cure you of hauling an expensive and high tech engine around, and ruining it with condensation collection, and lack of oil up on things. You did pay for it, you know, and you'll pay again if you wreck it through non-use (along with your battery in the cold, gheesh).

Obviously, few here have ever worked in a small engine shop with very predictable spring rush for lawnmowers and fall chainsaws, from engines allowed to sit for 6 months. I have. While there ARE ways to store engines long term - you're not doing it even for your lawnmowers and this is a lot more expensive and important to your life. IC engines are still a "use it or lose it" kind of thing, even this one.
 

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Sorry to dig up an old thread, but my question is along the lines discussed in this one. I would like to know the best ways (without a hack) to get the ICE to run as little as possible on my 12km round trip commute. The volt lives on a voltec 240 charger in my heated garage at night; drives for 6km in total about 10 minutes in the AM and I plug in the 120V while its at work. (albeit parked outside in the cold -15C on avg). I precondition at least once before i head home for the day, usually with a full charge and a warm car. Yet still the ICE runs a fair amount.

What can i do (climate setting wise/pre conditioning wise.. so on) to absolutely limit the amount my volt runs the ICE? I have a MY2013 with the Very Cold setting set.
 

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Old thread. I know DCFusor is still active and maybe he or someone else can answer my question. Today I drove my 3.5 mile commute to work in -17F temps. My ICE came on at least twice and the display said that I burned 0.07 gallons of gas. That's 50mpg and my battery is still fully charged (or very near fully charged).

My question is why is the ICE running? Which is it? Cabin comfort or engine maintenance? If it is strictly cabin comfort, I could certainly do without it for my 10 minutes on the road even at -17F (my MY2013 Volt is stored overnight in my garage at 60F). If it is for engine maintenance, then I'm fine with it running. However, all the documentation that I have read indicates that it is running for cabin heat only. Engine maintenance is never mentioned.

Is my battery really going to heat up from the engine or cool down from the weather significantly in my 10 minute drive? Is ERDTCT really effective in such a short duration? I would very much like to be able to tell the Volt that I'm only going 3.5 miles and to keep the engine off -- unless the engine is running for it's own health. And if the engine is running for its own health, why doesn't GM mention that anywhere?
 

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also with my 2013, since the outside temp. has been below 35F in the mornings for the last few days, I compared just letting it do the ERDTLT, vs. manually putting it in "Hold" mode early.

The gas mileage is better, if I put it in "Hold" mode soon after starting out and let it run for a few miles that way, than if I just run in Regular mode and let it decide when to do an ERDTLT.

now I don't know about initial ERDTLT vs subsequent ones, etc., if running Hold for a while delays additional ERDTLT's or not, and by how many minutes if so......
 

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gschuck: The engine is running to maintain the proper coolant temperature. The coolant is used to both warm the cabin, and maintain the battery temperature. For such a short drive, you could get away without the engine, but that is the way it's programmed. Keep the climate on COMFORT and the temp and fan all the way down and you will limit the number of engine cycles. COMFORT will use more battery power to maintain the coolant temperature. It will still come on once, but probably not more.

Also with a 2013, you can change the setting so the engine comes on at 15F rather than 35F. It's somewhere in the Configuration Menu.
 

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I have a 6 mile commute to work and have been testing this the past week. Outside temps have been around a low of -3f lately. I park in a garage maintained at about 40-50f. No matter what I do and what setting I have for climate (Comfort, ECO, Defrost, fan-only, etc) or how many pre-conditions I have done on 220, as soon as the display shows the temp at 14f, which is usually within about 60 seconds of pulling out of the garage, my engine will kick in to assist. It will randomly kick in about 4 different times on my short trip to work. I usually start out with full 29 miles showing on my charge and end up with around 26 miles left.

You can't tell me that a car that has been sitting at 50f for 12 hours needs an engine to assist it with heating within one minute of being exposed to cold temperatures. GM just took the lazy way out of the coding. They should have put a thermostat in the cooling unit and used that to code the engine-assistance-needed coding, rather than the outside temp.

Over the past 4 days, according to VoltStats.net, I have driven 141 EV miles, 0 gas miles and have used 1.8 gallons of gas. The only time I could see needing the engine to assist is on my drive home after my car has sat outside at -3f for 9 hours.
 

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I came across this thread when looking to see if anyone had actually implemented a working hack for avoiding ERDTT yet. I guess the answer is still "no" at this point(?).

I also found this: http://gm-volt.com/forum/showthread.php?11164-Hold-button-hack/page6 See Tboult's post (#54) for some good info about the outside air temperature sensor and a chart of temps vs. resistance values.

I'm not ambitious enough at this point to attempt it myself, but what's to stop someone from wiring a resistor with a relay switch in parallel with the outside air temperature sensor to reduce the effective resistance of the OAT and fool the car into thinking that it's warmer than it actually is? Idk where you'd route the wires to get them into the cabin, but if you did you could have a simple on/off switch and a few AA batteries to engage/disengage the relay.

Can anyone think of any risks to this approach? I'm not sure what else the OAT sensor might be used for, but I'm thinking that if the change in perceived temperature was relatively small, any unintended side-effects to the car's operation would be minimal.

(In that other thread that I linked to, the discussion was basically the opposite: it was about fooling the Volt into thinking that the outdoor air was colder in order to force ERDTT as a way to get a Hold mode in 2011-2012 MY's. Tboult mentioned using a peltier device to actually cool the OAT sensor. That could be an alternative approach compared to splicing in resistors and relays.)

gschuck: The engine is running to maintain the proper coolant temperature. The coolant is used to both warm the cabin, and maintain the battery temperature.
Not true about battery temp. The engine coolant loop is not physically connected with the battery coolant loop in any way. There is no exchange of heat between the two. The battery coolant loop has it's own electric heating element that manages the battery temp. See any one of the 1000's of posts about this.

Please let this myth die already.
 

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I'm not ambitious enough at this point to attempt it myself, but what's to stop someone from wiring a resistor with a relay switch in parallel with the outside air temperature sensor to reduce the effective resistance of the OAT and fool the car into thinking that it's warmer than it actually is? Idk where you'd route the wires to get them into the cabin, but if you did you could have a simple on/off switch and a few AA batteries to engage/disengage the relay.

Can anyone think of any risks to this approach? I'm not sure what else the OAT sensor might be used for, but I'm thinking that if the change in perceived temperature was relatively small, any unintended side-effects to the car's operation would be minimal.

(In that other thread that I linked to, the discussion was basically the opposite: it was about fooling the Volt into thinking that the outdoor air was colder in order to force ERDTT as a way to get a Hold mode in 2011-2012 MY's. Tboult mentioned using a peltier device to actually cool the OAT sensor. That could be an alternative approach compared to splicing in resistors and relays.)
Well, if you do get ambitious and make a workable hack, I suspect many Volt owners would be very interested. As you likely know, GM is in no rush to address either a ERDTLT "off" switch, nor a faux Hold mode using a different hack of the OAT sensor.
 
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