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Discussion Starter · #1 ·
Hi all,

I'm having a problem with my Volt and wondered if anybody had any advice. My 2014 Volt (30,000 miles) is losing 2 kWh immediately upon, or shortly after, start-up. Prior to start-up, the Volt's dash reads "Fully Charged", the battery gauge is full (estimated 39-45 mile range), the green charging light is off (flashing), and the Energy Used tab on the center screen is zeroed out. After start-up the green battery gauge loses two bars and reads '28 miles'. The energy used screen also shows 2.0 kWh used. This either happens immediately, or shortly after putting the car in 'D'. The car now gets 26-29 miles on electric before switching to gas after using 8 kWh. Prior to this issue, I was able to get anywhere between 39 and 47 miles per charge using 10.6 kWh.

I took the car in last Thursday, and the dealership still does not have a diagnosis. My service advisor confirmed that the technician was able to re-produce the problem, so it's not an issue with my charger or electric outlets. The dealership told me today that they have now reached out to GM Volt Service team to tell them what to do, but they have not yet heard back. Apparently this is an anomaly the dealership has never encountered before which has me concerned. Has anyone else had this problem or something similar?
 

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Haven't heard that one before, but good the dealer has repro'd it and is working on it. I wonder if the 12V battery is going bad and sucking down power to re-charge it upon car start (?)
 

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Discussion Starter · #3 ·
That's a good idea. The dealership told me they did a bunch of software upgrades which didn't solve the problem, but it did not mention the battery. I am going to pick up a loaner tomorrow, and I will make sure to ask if they tested the 12V battery. Other than this issue, the car has not given me any warning or error messages.
 

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A similar posting reporting a 10 mile range loss when driving only 2 miles was made by a forum participant from SE Michigan about four weeks ago:

http://gm-volt.com/forum/showthread.php?296570-10-mile-range-loss-when-driving-only-2-miles

The OP was concerned that his 2013 Volt with around 48k miles was behaving oddly. Sometime a full charge would be completed and only 8 or 9 green bars would be lit and the ev range estimate would be proportionally reduced. The car would then behave normally but with a reduced range. Sometimes a full charge would be completed and all 10 bars would be green and the full charge range estimate was as expected for a full charge, but after driving a few miles, the car would experience a very rapid use of ~2 kWh and the ev range estimate would drop ~10 miles. As the poster described it, "It acts like there's a 2 kwh "hole" in the battery that won't hold a charge."

It was as if the car would either "fully charge" to only 8 or 9 bars and get normal ev mileage from that amount, or would charge to 10 bars, and then quickly discharge 2-3 kWh shortly after first driving off for the day, and get normal ev mileage after that... as if some sort of battery degradation was either excluding a section of cells from charge, or charging them and then quickly shorting them out...

Unfortunately there was no further posting reporting what, if anything, the service people had determined. I just wanted to let you know someone else appears to have experienced a similar problem. If the problem was corrected, perhaps your service department can locate information in the GM data base. I also recall a thread from some time ago reporting the "less than 100% when fully charged" (or, only 8 or 9 green bars showing) condition, which I think was able to be corrected by that owner’s service department.
 

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Discussion Starter · #6 ·
Thanks for the links! I asked my service advisor if the techs tested the 12V, and he said they were way ahead of that. He called again this morning to tell me that GM Engineering has had to reach out to another engineer. He was not sure who that person was, but it does sound like they are on the case.

Reading the tale of two volts, I am starting to wonder if my daily commute has had an impact. I've recently started a daily 60-mile round trip commute. To my surprise, my Volt was performing better than ever by averaging 45-48 miles per trip before switching to Gas. I attributed this to rush-hour traffic and driving in 'L' instead of 'D'. The only other thing that changed is that I have to charge the car using the max 12 Amp option instead of the reduced 8 Amp to ensure it is ready the next morning.
 

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Discussion Starter · #7 ·
My service advisor called me this afternoon, and told me the technicians are working with engineering to diagnose the problem. The techs have tested every cell in the battery, and surprisingly the battery is in perfect condition. He told me if any cell was bad then the whole battery would be replaced, but every cell tested normal (3.9). My issue has now been escalated to GM's 'Platform Engineering' department since apparently this has never been encountered before.
 

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My service advisor called me this afternoon, and told me the technicians are working with engineering to diagnose the problem. The techs have tested every cell in the battery, and surprisingly the battery is in perfect condition. He told me if any cell was bad then the whole battery would be replaced, but every cell tested normal (3.9). My issue has now been escalated to GM's 'Platform Engineering' department since apparently this has never been encountered before.
In some perverse way going down in the history books as the first is neat! 8^p
 

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Discussion Starter · #10 · (Edited)
I am very upset with my dealership. My service advisor called me yesterday, and said the technicians solved my problem. After two weeks of diagnostics, their solution was to simply drain the battery pack entirely and charge it back it up. My advisor told me it was related to "battery memory", and the car was now holding a charge. The technicians did not replace any component in the car, and the advisor could not tell me what caused the problem.

Skeptical, I picked the car up yesterday. It was fully charged, but the battery gauge still had two bars missing at the top. The estimated mileage was 32, and the kWh used was 0.0. I pointed this out to the service manager, but he told me it looked normal. Bull. He ran through his spiel about how they worked with GM, and every diagnostic was normal so they couldn't replace anything. I drove the car home, and got 35 miles for 9.3 kWh before switching over to the ICE.

I plugged the car in overnight, and this morning the battery gauge was again full with an estimated 40 miles. I drove the car to work, and I watched the kWh Used gauge quickly go through the first 2 kWhs within a couple of miles. I also noticed the 'Driving Efficiency' gauge plummeted to 4-5%. At around the 3 kWh mark, the car's battery consumption slowed down and the efficiency gauge began to climb. Overall, I got 32 miles using 9.2 kWh this morning and the ICE did not come on. The efficiency gauge also climbed back up to 87%. This is an improvement, but a far cry from the performance I was getting just a couple of weeks ago where it only took 7 kWh to go 32 miles. I do not believe this issue is related to the weather or driving habits.

This looks like battery degradation, but the service department said the battery was fine. I'm thinking they just told me that to get the car out of the shop. I'm really at a loss for what to do next other than take it to another dealership. I do have a case number with GM that supposedly details everything they did.

Anybody have any advice?
 

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Discussion Starter · #11 ·
So I took my car to another dealership that serviced a lot of Volts, and they believe they found the problem. After extensive diagnostics, they discovered one of the three battery sections went bad. They ordered a replacement section, and I should (hopefully) have the car back next week.

This dealership also claimed to have never seen this problem before. The service manager even told me one GM TAC engineer said the car was fine, and to give it back. I think this is what happened at the first dealership I took it to. Fortunately, the techs at the other dealership pushed back and got another engineer that helped them find the problem.

I hope this helps anyone else who encounters this problem.
 

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The original Voltec warranty talks about 70% capacity retained after 100,000 miles or 8 years. How to assess capacity is the issue. I remember talking to my dealer about this, pre purchase, in 2014. They didn't really have a clue, but it came down to the diagnostic equipment computer pass or fail. If we have about 10KW usable new (gen 1), and still have 8KW available after 8 yrs, that should be within expected margin, and no remedy is warranted against capacity loss.

So good for GM to be addressing this. But I don't think it can be expected in all cases. And Bolt is even worse for documented warranty.
 
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