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Dealer called me back and didn't find anything wrong with the car.

The tech noted the following:
  • Diagnostic - He didn't find any issues reported during diagnostics
  • Availability - I was told I could pick it up or leave it over the weekend, but they'd like to perform additional testing to it on Monday (and call engineering).
  • Charging - He mentioned that he wanted to leave it charging over the weekend (the entire time), citing that the battery is climate controlled while plugged in, but that he did not believe the battery is climate controlled while operating on only battery. Is that accurate?
    • The car should be fully charged within an hour or two because of the limited capacity, so I wasn't understanding why they wanted to charge it for 3 days straight.
    • I mentioned that GM explicitly states to "Park your vehicle outside immediately after charging and do not leave your vehicle charging indoors overnight.", however, the tech only replied that the recall I mentioned is incomplete.
  • Repair - I noted that cell 51 appeared to exceed GMs specifications for battery degradation, and asked how long a battery repair would take. He noted that the repair would only take an afternoon, but part procurement might take longer (estimated a day or two). He also did not have any details regarding the battery replacement with old vs new battery packs.
I'm a little frustrated that they were not able to diagnose the details that my simple OBD2 scanner reported. The tech was essentially suggesting that this could be related to accessory usage or my driving habits. To confirm this, he wants to charge it for basically 3 days (which breaches GMs own guidelines), and he wants to monitor the consumption with his own driving experience on Monday, and follow up with a call to engineering.

My service advisor also mentioned that the normal EV tech is injured, and that he probably won't be returning. So I suspect that I have a technician who has very limited EV experience, because my area does not have a ton of EVs (Harrisburg, PA).

I was polite and respectful to them on the phone, but it sounds like they're just delaying the inevitable here.
I expected a frustrating experience, sorry you are not getting competent attention. How did they explain the voltage differential with cell 51, and what is their threshold for replacement? Did they give you a printout of the diagnostics?

I'm guessing nobody competent is there, so they are hoping they can pretend they are doing things to justify their existence, and that you'll just take the car and go away.
 

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My service advisor also mentioned that the normal EV tech is injured, and that he probably won't be returning. So I suspect that I have a technician who has very limited EV experience, because my area does not have a ton of EVs (Harrisburg, PA).
That could be a problem...
It's not uncommon for the trained EV tech to be the only person who knows what he is doing...
(Not totally. I have a local dealership that isn't bad now. Although they were like that for a couple of years...)

Is there another dealership with an EV tech you could take it to??
 

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Discussion Starter · #64 ·
I expected a frustrating experience, sorry you are not getting competent attention. How did they explain the voltage differential with cell 51, and what is their threshold for replacement? Did they give you a printout of the diagnostics?

I'm guessing nobody competent is there, so they are hoping they can pretend they are doing things to justify their existence, and that you'll just take the car and go away.
I only had a phone call at this point, but I think I can stop there after work to get a printout. The tech did not seem to have any reply for my cell 51 comment, other than he would document it in the notes. He did not state anything regarding threshold replacement either.
 

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Discussion Starter · #65 ·
That could be a problem...
It's not uncommon for the trained EV tech to be the only person who knows what he is doing...
(Not totally. I have a local dealership that isn't bad now. Although they were like that for a couple of years...)

Is there another dealership with an EV tech you could take it to??
I think I have some other EV certified dealers. I may check into this option, but will need to confirm my car can make the trip :unsure: lol
 

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It seems like this situation (I.e., one bad cell resulting in reduced range) has happened to enough people on this forum that Chevy should really code in some onboard diagnostics to screen for such discrepancies and provide some sort of warning or flag for the driver (and techs, apparently) analogous to a check engine light. There is entirely too much time wasted by owners having to diagnose their own problem and convince the dealer the problem exists. And it is only going to get worse as we move past the innovator and early adopter portions of the ownership curve.
 

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...Charging - He mentioned that he wanted to leave it charging over the weekend (the entire time), citing that the battery is climate controlled while plugged in, but that he did not believe the battery is climate controlled while operating on only battery. Is that accurate?...
Yes and no. The battery management system will maintain the battery temperature even if not plugged in, as long as the State of Charge is above 40%. However, the set points / triggers to start heating or cooling are less aggressive compared to being plugged in (ie - the BMS will maintain a narrower temperature range when plugged in).

...he wants to charge it for basically 3 days (which breaches GMs own guidelines), and he wants to monitor the consumption with his own driving experience on Monday, and follow up with a call to engineering.
That's not necessarily a bad thing. What's the target charge level?

There's been some speculation (without evidence) that the BMS does some sort of cell balancing only when charged to 100%. Other than that, we do have some reports from owners that the GOM and SOC can be miscalibrated, and that charging to full and discharging near empty one or a few times sometimes recalibrates those gauges.

Normally, when a Bolt owner sees something weird with their GOM and SOC, one of the suggestions would be to charge to 100% and discharge to near empty. But we shouldn't do right now that because of the fire risk. If your dealer tech does that under direction from GM's engineering center, better they take the risk than you.
 

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citing that the battery is climate controlled while plugged in, but that he did not believe the battery is climate controlled while operating on only battery. Is that accurate?
not completely accurate.

the car will condition if running on the battery. but the setpoints are different.

the car's setpoint is the lowest while plugged in and the car is on (cools to 27C, thinking it triggers at 30C).

the next setting is triggered at a higher temp when plugged in and not operating (don't know the value as car is off, appears to cool to 27C).

Then there's the not plugged in but the car is on (33C and cools to 32C).

Then there's the setpoint where the car is not plugged in but off (apparently works only if the battery is over 40% SOC, no idea how hot the battery needs to be to trigger cooling). So this apparently takes a pretty warm battery temperature. So it would almost appear that it doesn't happen. But many have reported a conditioning percentage change on the energy screen.
 

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Discussion Starter · #70 ·
I picked my car up. Wasn't comfortable leaving it plugged in. They didn't give me any paperwork, but the manager saw it fully charged to 85 miles on the GOM. He took a picture and told me he'd pass the info to the tech. I'll know more Monday, but the manager seems to agree something is wrong at least.

Here is my SoC var:

Font Auto part Number Circle Logo
 

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That tech seems like they are trying but is obviously very underinformed. The bad cell group is probably sagging below 3.0v under load up a hill. You could check that on Torque. It is toast. And seems like a very dangerous situation each time you charge it. The best case failure at this point would be that the car quits and strands you at the side of the highway somewhere. Which is still pretty bad. The worst would be a fire. If you bought it new, that selling dealer owes you a loaner car. Period. Call GM and open a case, And park the car.
 

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Discussion Starter · #74 ·
Quick update, they never called on Monday. I decided to call my service advisor late morning on Tuesday, and left a voicemail asking for their resolution. The service manager called back in the afternoon and asked if I could drop the car off. He said he was working with GM over the phone, and they mentioned (and agreed) that they could see something is wrong with the car. I dropped it off over lunch on Tuesday, and they shuttled me back. The service manager noted that they might have the car awhile. He said a module / battery pack replacement wouldn't take long after they receive the part (if that is the issue of course). Really kicking myself now for letting the C5 inspection lapse :rolleyes:
 

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He said a module / battery pack replacement wouldn't take long after they receive the part (if that is the issue of course). Really kicking myself now for letting the C5 inspection lapse :rolleyes:
Will be fascinated to see how this goes. GM said they will not be replacing any battery sections until they are sure they have defect free cells. I will be very interested to see if they break their own decree in your case. I wonder if it is even up to them, since this is the "plan" they have summitted to the NHTSA.
 

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Will be fascinated to see how this goes. GM said they will not be replacing any battery sections until they are sure they have defect free cells. I will be very interested to see if they break their own decree in your case. I wonder if it is even up to them, since this is the "plan" they have summitted to the NHTSA.
Since the repairs are not recall related, GM is free to replace the battery (or battery modules) as they normally would. The recall simply remains open.
 
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