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Possibilities.
1. The 12 V battery is failing
2. 12 V charging system is messed up
3. Something is draining the 12 V system
I am guessing # 1.
Your thoughts and analysis are welcome.:(
I agree with your first "guess". I know someone who bought a 2014 Ford Fusion Hybrid that was sitting on the dealer's lot for almost a year. After two moths of driving it, the 12VDC battery (which is mounted in a special space inside the fender on the driver's side of the trunk - a better idea than up front) went bad and he couldn't start the vehicle even though it allowed the fob to unlock the doors. As in all hybrids and BEVs, it is used to start up the vehicle, and needs a HVDC to 12VDC converter to charge it so he had to "jump start" the battery to get the vehicle operational. Since it was still new, he drove it to the dealer, who swapped the battery for free under factory warranty. The dealer confirmed that the battery was bad and the converter was working correctly.

If the EV was parked for a long time, that 12 VDC battery can fail. As Volt owners already know, keeping the EV plugged in while unused will keep both that 12 VDC battery and the HV tracion battery well charged. But for a plain non-plug hybrid, it needs to be started up once a month or sooner.
 

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Discussion Starter #45
Actually the problem was that when it was being driven, the charging system thought it was in service mode and the battery was not being charged. A software issue in the transmission module.
If you go back up in the thread this is described in gruesome detail. One clue was each of the three failures was at least 7 days after charging the HVB.
:nerd:
I agree with your first "guess". I know someone who bought a 2014 Ford Fusion Hybrid that was sitting on the dealer's lot for almost a year. After two moths of driving it, the 12VDC battery (which is mounted in a special space inside the fender on the driver's side of the trunk - a better idea than up front) went bad and he couldn't start the vehicle even though it allowed the fob to unlock the doors. As in all hybrids and BEVs, it is used to start up the vehicle, and needs a HVDC to 12VDC converter to charge it so he had to "jump start" the battery to get the vehicle operational. Since it was still new, he drove it to the dealer, who swapped the battery for free under factory warranty. The dealer confirmed that the battery was bad and the converter was working correctly.

If the EV was parked for a long time, that 12 VDC battery can fail. As Volt owners already know, keeping the EV plugged in while unused will keep both that 12 VDC battery and the HV tracion battery well charged. But for a plain non-plug hybrid, it needs to be started up once a month or sooner.
 

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Discussion Starter #46
About two weeks later and guess what? I drove out of Berkeley to take a hike. I returned from the hike at sunset and the Bolt said not ready, battery saver mode, showed the red batter symbol instead of the green ready. OK, I have been there before. See above. I thought it was solved with the last trip to Fremont Chevrolet. I called Chevy Road Assistance and they were unable to locate any help (I was only 3 miles outside the Berkeley city limits). It was getting cold and totally dark so I had my wife drive out with jumper cables and her 2006 Acura. I jumped that sucker, it only took about a minute, until it cleared the error signals and would "start". Drove 5 miles home, tested the 12 V battery after it had settled and it read 12.6 V. This is getting mysterious. If it was discharged, how could it recharge that fast? Among the error messages was "Service Charging System". Duh! So I guess all the software changes the made that are referenced above didn't solve the problem. So its back on the EVSE which does seem to charge the 12 V system and I will have to arrange another fun forty mile trip to Fremont Chevrolet. Walnut Creek Chevrolet is closer but last time I called them they said the earliest appointment was two weeks.

Love this car, but after failing to start four separate occasions I wouldn't call it reliable transportation.
 

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Love this car, but after failing to start four separate occasions I wouldn't call it reliable transportation.
This is what I am worried about. Mine is two weeks old demonstrating the same issue except when coming back the next morning to meet the tow truck, it was completely dead. Then the next morning after being towed to the dealer, the dealer found it miraculously fully powered and operating normally. It was throwing codes and OnStar emailed me the following statement the next morning: "A critical issue with the engine and transmission system in your 2017 Chevrolet Bolt EV has been detected. Please service your vehicle immediately."

The dealer has had my Bolt for 3 full days now and not a word even after emailing my service adviser asking for updates. Which is very interesting to me because I have known my service adviser for years and he has always been on top of things.

There are others suffering the same exact issues as well. For me personally this is a very serious issue. I am not going to pay this kind of money for a brand new vehicle that I have no confidence will work each and every time I go to use it.

I trust GM will find the issue and get it resolved. Better man than me. I am not sure how many times I would put up with it being towed and they will tow it each and every time I cant drive off in it, which I hope is never again!
 

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Discussion Starter #49
You read my mind. That looks very cool. At one level, it seems to me Chevrolet should figure out what is wrong and fix it. At another level, my confindence in that approach is rapidly sinking.
If this goes on, I might buy one of those devices.
:nerd:
These problems where the 12V system seems to be suspect are really crying out for some sort of voltmeter that can log data. Something like this, perhaps...
 

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Discussion Starter #50 (Edited)
This is what I am worried about. Mine is two weeks old demonstrating the same issue except when coming back the next morning to meet the tow truck, it was completely dead. Then the next morning after being towed to the dealer, the dealer found it miraculously fully powered and operating normally. It was throwing codes and OnStar emailed me the following statement the next morning: "A critical issue with the engine and transmission system in your 2017 Chevrolet Bolt EV has been detected. Please service your vehicle immediately."

The dealer has had my Bolt for 3 full days now and not a word even after emailing my service adviser asking for updates. Which is very interesting to me because I have known my service adviser for years and he has always been on top of things.

There are others suffering the same exact issues as well. For me personally this is a very serious issue. I am not going to pay this kind of money for a brand new vehicle that I have no confidence will work each and every time I go to use it.

I trust GM will find the issue and get it resolved. Better man than me. I am not sure how many times I would put up with it being towed and they will tow it each and every time I cant drive off in it, which I hope is never again!
Sorry to hear you are having trouble, but glad to know I am not the only one. At least with mine, it can be jumped and after a while the 12 V system reaches a value, the error messages clear and I can then "start" it up and drive it. This last time, I didn't try to shift it and never got an error message about the transmission. Of course the last time they "fixed it" the loaded new code into the transmission module. I have the sense that the four or five times it has run the 12 V system down it may have damaged the battery capacity. I had my car for about 6 months before the first failure. By the way, service advisor know next to nothing, and it is maybe one tech that has the information, buy they are hidden from the customer. At least that is how Fremont Chevrolet works.:mad:

Keep us (and me) informed with this problem.
 

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This is what I am worried about. Mine is two weeks old demonstrating the same issue except when coming back the next morning to meet the tow truck, it was completely dead. Then the next morning after being towed to the dealer, the dealer found it miraculously fully powered and operating normally. It was throwing codes and OnStar emailed me the following statement the next morning: "A critical issue with the engine and transmission system in your 2017 Chevrolet Bolt EV has been detected. Please service your vehicle immediately."

The dealer has had my Bolt for 3 full days now and not a word even after emailing my service adviser asking for updates. Which is very interesting to me because I have known my service adviser for years and he has always been on top of things.

There are others suffering the same exact issues as well. For me personally this is a very serious issue. I am not going to pay this kind of money for a brand new vehicle that I have no confidence will work each and every time I go to use it.

I trust GM will find the issue and get it resolved. Better man than me. I am not sure how many times I would put up with it being towed and they will tow it each and every time I cant drive off in it, which I hope is never again!

Good news I hope!! My service adviser called late today just to let me know it will be going into detail tomorrow to clean the seat and buff out the scratches on the hood. I can pick it up tomorrow.

The issue as he relayed it to me was they found a "draw" and replaced the MPCM2 module (I think, he was going fast) which is the main charging system control. I will know more tomorrow when I pick up the car and can read the lengthy report (as he put it).
 

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I think there is a Lemon Law here and if it has been to the dealer 3 times then they have to keep the car. I think you get another one or the price for it ?? Not sure how the end result would be.

I would be telling them top take the car back !
 

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Discussion Starter #53
I think there is a Lemon Law here and if it has been to the dealer 3 times then they have to keep the car. I think you get another one or the price for it ?? Not sure how the end result would be.

I would be telling them top take the car back !
Not sure where he is from, but no Lemon Law in California.
 

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For those of us having these issues here is the service report for mine. Interesting that they did not explain how it was dead and needed towing only to find it working great the next morning.
 

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Discussion Starter #57
For those of us having these issues here is the service report for mine. Interesting that they did not explain how it was dead and needed towing only to find it working great the next morning.
Thanks for the service report. Taking mine in Tuesday (for the third time) to see if they can figure out what is either randomly draining the battery or randomly failing to charge the 12 V system. This is getting really irritating.:nerd:
 

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Parents seem to be having the same problem with their newly acquired Bolt lease. So far we have not had this issue with ours. Subscribing for updates.
 

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I thought that AGM is still a lead acid battery, but with a glass mat as an electrode.
Nope not the electrode, it holds the electrolyte, better than a traditional lead acid. I cant say it better than:

http://batteryuniversity.com/learn/article/absorbent_glass_mat_agm

"
AGM technology became popular in the early 1980s as a sealed lead acid battery for military aircraft, vehicles and UPS to reduce weight and improve reliability. The sulfuric acid is absorbed by a very fine fiberglass mat, making the battery spill-proof. This enables shipment without hazardous material restrictions. The plates can be made flat to resemble a standard flooded lead acid pack in a rectangular case; they can also be wound into a cylindrical cell.

AGM has very low internal resistance, is capable to deliver high currents on demand and offers a relatively long service life, even when deep cycled. AGM is maintenance free, provides good electrical reliability and is lighter than the flooded lead acid type. While regular lead acid batteries need a topping charge every six months to prevent the buildup of sulfation, AGM batteries are less prone to sulfation and can sit in storage for longer before a charge becomes necessary. The battery stands up well to low temperatures and has a low self-discharge.
"
 
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