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2012 Switches to gas mode with Battery Charge remaining

19428 Views 52 Replies 22 Participants Last post by  hellsop
I have a 2012 Chevy volt with 140,000 miles. It has not had any issues until now. The car will switch to gas mode while there is still plenty of charge remaining in the battery (as much as 80%). The temperature is well above freezing. Stopping, shutting of the car off and restarting resolves the issue. I took it to the dealer. however, the computer was not writing any errors codes.

Any ideas what could be causing this?
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Five figures if you do it the easy way. A cell bad enough to stop the car means traction-battery replacement, and since GM isn't doing battery modules anymore, the's the whole thing.
The hard way is doing your own sourcing of battery from salvage and likely your own work because dealerships won't touch it and there's basically no 3rd-party Voltec service techs out there, and even then it's probably going to approach Van Frier sent you.
they will replace just the bad cell or what ever it needs. Whole sets refurbished is about $4500
typically it will switch back to electric after it burns .07 or .10 gallons of gas. similar to a engine run due to 25 deg ambient temp. However, it works pretty hard to increase the state of charge. You can see this in the third graph in the excel file
I have a 2012 Chevy volt with 140,000 miles. It has not had any issues until now. The car will switch to gas mode while there is still plenty of charge remaining in the battery (as much as 80%). The temperature is well above freezing. Stopping, shutting of the car off and restarting resolves the issue. I took it to the dealer. however, the computer was not writing any errors codes.

Any ideas what could be causing this?
My 2012 Chevy Volt with 115,000 miles recently (Feb. 2023) developed the same problem.
make sure to scan all the message but I don't think you would miss the BIG BURN messages.
I seem to have fixed the problem, It is the Temp sensor under the overflow tank by the radiator on the left side. I noticed that my 2012 would switch when outside temp was under 50 degrees and I would hit a bump or ruff spot in the road. I used the long screw driver to reset the reservoir, took the car to Greentech and had codes re moved. I was still getting full charge to ICE but it was better. I lifted the cable under reservoir and pushed it up where sensor was closer to magnet in reservoir tank and unhooked the Battery in trunk of car for a few minutes to let it clear CPU and re-hooked it so it could re-cycle CPU. I had to do this twice and it took a couple of days to reboot everything and all seems fine.. It was 52 degrees this morning and it started on Battery and stayed on Battery for as long as I was driving. I only get about 26 to 27 miles to a charge. I wish I could get twice that all would be well in the world but that's not going to happen. Good luck. Van
I seem to have fixed the problem, It is the Temp sensor under the overflow tank by the radiator on the left side. I noticed that my 2012 would switch when outside temp was under 50 degrees and I would hit a bump or ruff spot in the road. I used the long screw driver to reset the reservoir, took the car to Greentech and had codes re moved. I was still getting full charge to ICE but it was better. I lifted the cable under reservoir and pushed it up where sensor was closer to magnet in reservoir tank and unhooked the Battery in trunk of car for a few minutes to let it clear CPU and re-hooked it so it could re-cycle CPU. I had to do this twice and it took a couple of days to reboot everything and all seems fine.. It was 52 degrees this morning and it started on Battery and stayed on Battery for as long as I was driving. I only get about 26 to 27 miles to a charge. I wish I could get twice that all would be well in the world but that's not going to happen. Good luck. Van
Thanks, Van. Sounds promising. I too currently get only about 23 - 25 miles on a full charge. I live in an area (Fresno, CA) where nights and sometimes days go below 50 degrees, And yup, when I hit a bump, make a turn, or accelerate, the switch flips power from batteries to gas to back again, randomly.

I do not know how to fix the car myself, but I will take your description of what you say worked for you to a Volt repair service center and see what they can do with your advice.

Thanks again.

Fred


Fred
Fresno
Thanks Fred and Van,

My 2011 Volt (155,000 miles) only gets about 19 miles per charge on cold days, but even more aggravating is that it mostly runs on the generator even when the the battery has miles showing. Van I'm interested to know if your solution is holding strong. If so, do you think the GreenTech service in Hayward (I'm in Oakland) would be able to follow your instructions? I'm not sure what you mean--"I'm still getting full charge to ICE, but it was better."

Thanks for any advice!

--Jack
Sorry I can't give you much advice.
Prior to my communication with Van, I took my 2011 Chevy Volt to a local Chevy/Cadillac service center (Fresno CA) to address the problem of the premature switch to gas. They were not able to do anything about the problem during the two days I left the car with them.
I have not tried to take the car to a service center after the communication with Van.
My Volt currently gets about 24 miles on batteries fully charged.
It would be great if GM people would look into this website and talk to us about what to do, or what to tell service centers to do, about the premature switch to gas problem.
I have noticed a gravity factor: when I ramp up to a freeway and accelerate, the switch to gas seems to happen inevitably; when I descend down a ramp to a freeway and accelerate, the car stays on batteries. Weird.
Fred
If Van was referring to the battery coolant level sensor, replacing that part did not solve this problem for me. I replaced it with an SHVCS defeat plug to completely eliminate the faulty sensor from the situation. Unfortunately, this problem just seems like the result of a degrading high-voltage battery.
Thanks Fred and Tendies!

I'm wondering if anyone has replaced their batteries and found that this fixed the running-on-ICE-when-there-is-charge-on-the-battery problem. I would hate to go to the expense of replacing the batteries and then have the problem still happening.

--Jack
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As an original owner of a 2011 Chevy Volt, I am beginning to think that, as 575 suggests, the diminishment of the original battery pack's reserved power weakens the signal for when gas should kick in. Prematurely, we now find. Does anyone know what the cost of replacing the battery pack in a 2011 Chevy Volt would be? I have seen estimates online that range up to $30k. Maybe a new set of batteries is the only answer to this premature switch-to-gas problem. If so, the solution might cost almost as much as a new car.
As an original owner of a 2011 Chevy Volt, I am beginning to think that, as 575 suggests, the diminishment of the original battery pack's reserved power weakens the signal for when gas should kick in. Prematurely, we now find. Does anyone know what the cost of replacing the battery pack in a 2011 Chevy Volt would be? I have seen estimates online that range up to $30k. Maybe a new set of batteries is the only answer to this premature switch-to-gas problem. If so, the solution might cost almost as much as a new car.
$7500-15k depending on year and whether you get refurb or just battery sections mixed and matched with tested cells in from Greentec. I don't know if we've heard how much GM is charging for replacement batteries but they at least have a program to do that now, and the software to support mixed chemistries.
$7500-15k depending on year and whether you get refurb or just battery sections mixed and matched with tested cells in from Greentec. I don't know if we've heard how much GM is charging for replacement batteries but they at least have a program to do that now, and the software to support mixed chemistries.
The premature switch from electric to gas that I had been experiencing with my 2012 Volt HAS CEASED! Best guess as to why: the weather in my area (Fresno CA) has gotten warmer, the batteries charge more fully in warmer weather (26-27 miles vs. 23-24 miles), with the result that the switch to gas does not happen until batteries have fully depleted.
I don't know if we've heard how much GM is charging for replacement batteries but they at least have a program to do that now, and the software to support mixed chemistries.
The battery upgrade kit discussion: TSB 19-NA-242 GM Gen 1 Battery Pack Refurbish Kit
The premature switch from electric to gas that I had been experiencing with my 2012 Volt HAS CEASED! Best guess as to why: the weather in my area (Fresno CA) has gotten warmer, the batteries charge more fully in warmer weather (26-27 miles vs. 23-24 miles), with the result that the switch to gas does not happen until batteries have fully depleted.
That's probably not a "fuller charge" if it got a full, overnight opportunity to both charge and run a balance cycle, but rather less climate control and battery temperature management, and higher tire pressure.
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