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Discussion Starter · #1 ·
Curious if anyone has had a confused state of charge after your high voltage battery was repaired, and how you had it fixed. I will now need a FOURTH unexpected service visit for my 2017 with 3000 miles. I'll describe the issue that preceded my confused state of charge.

Had the dreaded "shift to park" message I've seen lots of posts about. Fortunately, mine occurred in a parked state, and not while in motion. Volt was towed to dealer. Dealer diagnosed with codes: U2603, U2604, U2605, U2617, U2618. Cells 1-44 were reading 0 volts. First attempt to fix was with a Hybrid Powertrain Control Module 2 (part 23273890), that did not resolve the issue. Second attempt to fix was a Battery Energy Control Module (part 24283058), which meant the battery pack had to be lowered and taken apart. The second part "fixed" the issue. When the vehicle was returned to me, it indicated 8 bars of charge with 13 miles of range, dealer said drive it to recalibrate.

I've driven it some, and after a full recharge of 4.5 hours on a 240V EVSE, my Volt switches to gasoline mode after 3.8 kWh used. Photo below. But the car is still finding additional energy in the battery, so the gasoline is being used sparingly, but I can say the engine comes on periodically through this strange operating mode.

Anyone else see this after their high voltage battery was serviced, and how was it resolved? I've got ANOTHER appointment to get my Volt looked at. If anyone is reading this and hasn't purchased a Volt, my recommendation is to not buy. This is my second Volt, but this second generation is a rattle trap and poorly manufactured. 3 months of ownership, 3000 miles, 17 days out of service, so far.

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I would hope folks would offer up the last 5 digits of their VIN's when these things occur. It will help paint a better picture of the scope of the problem. Usually a small range of VIN's are involved usually indicating a faulty part or manufacturing glitch that GM can quickly ID and fix.

But so far I haven't seen anyone share that info with us.
 

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Discussion Starter · #6 · (Edited)
This sounds like ERDTT. But your photo says the weather isn't cold enough. Maybe there is a bad temperature sensor?
My problem is not ERDTT. As a driver of Gen1 and Gen2, I am familiar with ERDTT. As you can see it's not cold enough. Also, the battery gauge went from full to empty for the 3.8 kWh / 17 miles displayed since full charge. I had to pull off the road to take the picture in my first post. Then the Volt magically found 3 more "bars" of charge, but stayed in gasoline mode. You can see it's in gasoline mode by the blue glow on the right gasoline gauge. And even though there are 3 more bars of charge again, the EV range indicates 0 miles. Here's the main instrument cluster:

Land vehicle Vehicle Car Motor vehicle Multimedia


Here's a photo of the full drive after I drove all the way home. This demonstrates that the gasoline is being used very sparingly in this confused state of charge gasoline mode:

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It definitely seems like there's an issue with the charge sensing circuit. If it's saying there's charge in the battery, but 0 EV miles, there's a logic problem there. Mine said it was 100% with 0 EV miles when it broke; it was a charge sensing issue but the root of my problem was a bad cell. You said they told you that 44 of the cells were reading 0 volts; there's a chance that the battery controller may have damaged those cells when it lost communication with them. Either that, or they didn't really fix your battery controller issue. You may want to find a different dealer if you're not having luck with your current one.
 

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Discussion Starter · #8 ·
It definitely seems like there's an issue with the charge sensing circuit. ..... may want to find a different dealer if you're not having luck with your current one.
Thanks for your response! I did call Chevrolet customer service and their recommendation is to stick with the same dealer right now since it seems related to the Shift to Park repair. I'm going to give the same dealer a chance to make it right again, but they're making me wait a week for their next appointment. Until then, I have to drive the Volt with the broken battery gauge and gasoline modes. If the same dealer fails to fix it on a second look, then I'll switch to another one in area. The dealer basically doesn't believe me, and I provided them even more photographic evidence than I've provided the forum. Fortunately the issue is reproducible, but the dealer doesn't want to spend the time driving the Volt around to see the strange behavior.

More power to Tesla, I can't wait to see the dealer lobby fail! I find it so ironic that they go to the argument that dealers are better for service, when that is my exact opposite experience.
 

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Thanks for your response! I did call Chevrolet customer service and their recommendation is to stick with the same dealer right now since it seems related to the Shift to Park repair. I'm going to give the same dealer a chance to make it right again, but they're making me wait a week for their next appointment. Until then, I have to drive the Volt with the broken battery gauge and gasoline modes. If the same dealer fails to fix it on a second look, then I'll switch to another one in area. The dealer basically doesn't believe me, and I provided them even more photographic evidence than I've provided the forum. Fortunately the issue is reproducible, but the dealer doesn't want to spend the time driving the Volt around to see the strange behavior.

More power to Tesla, I can't wait to see the dealer lobby fail! I find it so ironic that they go to the argument that dealers are better for service, when that is my exact opposite experience.
Dealers are definitely not going to be as reliable as a centralized maintenance location because the mechanics are probably not going to be certified as rigorously. The dealer that sold me mine didn't take care of it while it was on the lot. Tires were ~10psi below recommended, fuel was the original year-old fuel (which fouled the plugs), fuel maintenance mode kicked in when I took it home which means it was hardly driven in the 4 months it was on the lot, and they didn't perform the 3 open recalls on it before selling it.

I've been taking it to a dealer closer to me for my plethora of issues and they've been a lot better, but I still think a centralized maintenance facility would have found and fixed my battery issue in half the time.
 

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Discussion Starter · #10 ·
Just a follow up to this thread on the fix to my issue.

When I dropped it off to the same dealership for repair, the car was ranging between 9-30 miles of EV range before starting to engage the gasoline generator. I provided the dealership with detailed day by day records. The technician contacted TAC (technician support at GM) and they instructed the technician to "reset battery learn again". After this the dealership did extensive test driving and determined the battery was operating normally again.

After I got the car again, I can confirm it fixed the issue. So if you have very strange battery behavior like this, it seems that software resets can solve it.
 

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Just a follow up to this thread on the fix to my issue.

When I dropped it off to the same dealership for repair, the car was ranging between 9-30 miles of EV range before starting to engage the gasoline generator. I provided the dealership with detailed day by day records. The technician contacted TAC (technician support at GM) and they instructed the technician to "reset battery learn again". After this the dealership did extensive test driving and determined the battery was operating normally again.

After I got the car again, I can confirm it fixed the issue. So if you have very strange battery behavior like this, it seems that software resets can solve it.
I wonder if that's something that can be done with OBD-II commands. I highly doubt it, but it would be interesting.

My range has been in the low 40s since getting my new battery segment, but I'm attributing that to the fact that it's about 40-50 degrees colder than when I first got my car towed to the dealer. We shall see in a few months if it goes back up to the high 50s where it used to be...
 

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I've had two HV issues since June, one just last night. Towed to dealer today. I can post the fault codes if anyone is building a database.

My last 5 are: 04348


Thanks,
Adam
 
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