[cwerdna]

Press the blue OnStar button to ask for a report of the DTCs.

 

[mobythevan]

Ok, here is another:

2020 Bolt LT that I bought new
Diagnostic software installed Aug 29th, mileage 48708
Code U362A detected September 23rd at mileage 50894
Service scheduled Sept 26th so I will keep everyone updated.

NOTES:
I commute 140 miles per day, charge every week night
Car threw code first thing in morning after an overnight charge to 80%

I don't read the forum much so I scheduled service and the guy said no problem to keep driving it with reduced propulsion. So I took it out to test what reduced meant and noticed no AC. Then looked at forum and realized battery is likely not cooling. So I came home and then observed it would not charge back up to 80% as others stated. Then it was making sounds kind of like boiling coolant in traction battery under the car. I caught some video with the sounds. That was yesterday, parked it at safe distance from everything. This morning checked on it and still making the sounds. I had the car started today while calling onstar, and no the sounds are gone. But they were loud enough to hear in the car while talking to onstar. Hard to tell if it was gurgling or like plastic heated and making noises. If I drive the car to the dealer on Tuesday it is 35 mile trip.

Also, Dealer is no help for rental or loaner as others have stated. And onstar said tow bill would be on me even though I described the sounds it was/is making. Typical.

I got the car back this morning with a new battery. Everything seems good. Can charge to 100%. Was about 2 weeks. And the dealer set up a 2023 Bolt rental for me while they did the work. I did call the EV concierge. So far happy ending.

 

[Just Me]

UPDATE: Just got the car back. I saw the fault report when I picked up the car. It was a code "U3636 Section 9". They flashed new software.
View attachment 60496

The service advisor said this did NOT reset the 6000mi countdown to 100% charge.

Does anyone know what this software "fix" does? What is actually causing the fault? Anyway to find out? Noting how quickly the fault appears after the previous diagnostic update, how did they not find this in testing?

So many questions, never any answers from GM.

 

[DesertBolt]

Does anyone know what this software "fix" does? What is actually causing the fault? Anyway to find out? Noting how quickly the fault appears after the previous diagnostic update, how did they not find this in testing?

So many questions, never any answers from GM.

I believe that this software is not a "fix" but a very precise monitoring package. I don't work for GM, but I do have over 10 years experience working on heavy duty vehicles that have been converted to have either hybrid or pure electric drivetrains.

I presume this software monitors the cells very closely for any unusual activity regarding voltage and temperature. It's probably looking for changes in voltage and temperature that are outside an expected rate. Cells warm up as they accept/give up energy. If one starts to run away in either voltage or temp while charging, it can shut everything down to prevent a fi... I mean a thermal event. And flag a check engine light, or the pack for replacement.

The first software that limited charging probably had volt/temp limits that were too tight. This latest one probably has limits that allow for a bit more variance between cells.

 

[GJETSON]

The first software that limited charging probably had volt/temp limits that were too tight. This latest one probably has limits that allow for a bit more variance between cells.

I agree with your assessment. The temperature reading is going to be pretty useless against thermal runaway, however...with only 6 of the 10 modules having a single thermistor at one end of a 24-30 cell module, by the time it sees a significant temperature rise, the cell will likely be venting.

 

[Just Me]

I believe that this software is not a "fix" but a very precise monitoring package. I don't work for GM, but I do have over 10 years experience working on heavy duty vehicles that have been converted to have either hybrid or pure electric drivetrains.

I presume this software monitors the cells very closely for any unusual activity regarding voltage and temperature. It's probably looking for changes in voltage and temperature that are outside an expected rate. Cells warm up as they accept/give up energy. If one starts to run away in either voltage or temp while charging, it can shut everything down to prevent a fi... I mean a thermal event. And flag a check engine light, or the pack for replacement.

The first software that limited charging probably had volt/temp limits that were too tight. This latest one probably has limits that allow for a bit more variance between cells.

Yes. I had a 20 year career dealing with very large complex software systems. I understand the first update this summer is a diagnostic package designed to identify if the battery has a defect. Given how long it took GM to come up with this solution, I would have expected them to have tested it extensively. Once it was deployed, it seemed to be be failing (or is it succeeding?) within a few hundred miles. Now they have very quickly released a patch to the diagnostic software. So what is it that this patch fixes? It could be an adjustment to the sensitivity of the diagnostic, as you say. But then how do they know they haven't gone too far the other way with only a couple months testing? Or it could just be a random bug that has nothing to do with the sensitivity. In either case, why didn't they see the problem while testing the original update? My engineering Spidey Sense is tingling. After the way GM has behaved over the last couple of years, I find it very hard to trust that they know what they're doing.

 

[Just Me]

I agree with your assessment. The temperature reading is going to be pretty useless against thermal runaway, however...with only 6 of the 10 modules having a single thermistor at one end of a 24-30 cell module, by the time it sees a significant temperature rise, the cell will likely be venting.

Ok. How does this apply to my scenario...
That fateful morning I started my little Bolt around 9am with about 40% charge. I drove 19 miles in light traffic on city streets to a volunteering gig. I was there two plus hours. Went back out to my car and when I started it, the warning alarm was blaring. It let me silence the alarm and I drove home. The only other symptom I noted on the drive was the lack of AC. i arrived home with about 30% charge. It will now only charge to 35%.

In the two weeks between the time I had the software update installed (Which, BTW, was two weeks after the bulletin about the second release/ patch. So, not clear which version I actually got.) and the morning it faulted, I had driven about 150 miles and charged the car twice.

 

[GJETSON]

Ok. How does this apply to my scenario...

There have always been 3 specific fault codes for each of the 96 cell groups,
The faulted cell group does not change voltage.
Any cell group voltage signal is less than 1.75 V.
Any cell group voltage signal is greater than 4.58 V.

and one for the pack.

The hybrid/EV battery energy control module detects high resistance on the circuit.

Perhaps they were able to add looking for rate of change...a cell group voltage decrease, or increase, significantly faster than the others during acceleration, or regen?

 

[MichBolt]

...the warning alarm was blaring. It let me silence the alarm and I drove home...

The blaring alarm was originally added in one of the earlier software updates to warn of a thermal ruanaway - ie, a fire. I'm surprised that (1) it let you silence the alarm, and (2) let you keep driving it afterwards. Clearly, they've decreased the threshold for the alarm, but now allow you to ignore it.

 

[Just Me]

Here's mine.
2020 Bolt Premium, purchased new
Date: 10/6/23
Diagnostic Code: Don't know yet
Software patch installed: Sept 27, 14396 m
Miles driven before detection: 140

In July I got the notice for the diagnostic software update. Took it in and the service guy said: Nope, you're actually getting a new battery, 6 week wait. Checked back after 7 weeks: Nope, that was wrong info, you're getting the software update. Got the update. Based on what I've seen here, hopefully I got the latest updated patch?

Two weeks later, today, got the warning light and "propulsion power reduced" message. NO A/C IN TUCSON IS UNACCEPTABLE! By the time I could get anyone at the dealer to answer the phone, it was too late to take it in. Scheduled for 8am Monday to diagnose the problem.

I'll let you know how it goes.

Here's the next chapter in my story. Got up yesterday morning to a flat tire. Argh! Fortunately, we have a compressor, so I was able to get it aired up and drove the 5-ish miles to the dealer. Got it all checked in and and the service rep provided an Uber home.
Middle of the afternoon, he calls and says, yes, the battery has a fault and GM will be getting me a new one. He said that the process for them to order a new battery has changed and mine is the first one for him with this process, so he's not sure about the wait time. For now, he's estimating 4 to 6 weeks.
He set me up with a rental through Enterprise, completely covered by GM. It turned out to be a brand new Volvo CX40 EV that they had just received!
Big sigh of relief!

 

[stormann59]

My 2020 premier ac stopped working took it to the dealership for repair, but they said it was out of warranty got charged for repair. Had software updated to the latest and greatest!

 

[GJETSON]

He set me up with a rental through Enterprise, completely covered by GM. It turned out to be a brand new Volvo CX40 EV that they had just received!
Big sigh of relief!

That is terrific. If we ever need any more work on our Bolt, we will be asking our Leaf owning neighbor to drive us to Richmond for a Model 3. No more ICE rentals...ever.

 

[phxsmiley]

I just got word back from the dealership that they will be replacing the battery.
Date: 10/2/23
Diagnostic Code: U3624
Miles driven before detection: 925
How long to get new pack: 7
Car Build Date: 03/21
Took about 7 days before I could take it into the dealsership. They took about 1.5 days to diagnose the pack and test it. New pack arrived in about 7 days, took about 2 more days to install and test.
Meanwhile, EV Concierge is reimbursing me for a rental car at $50/day

 

[AdrianC]

Mine is going back to the shop again. Propulsion power reduced this morning.
No out of the ordinary use. Charged to 80% last night like normal.
Booked in for Monday morning. Will it be a third software update, or a third new battery, or both? lol.
I expect it just needs the new-new-new, less sensitive advanced diagnostics software.
Great car. GM software, not so much.

Edit: Just read the codes: U3636
Second edit: Just dropped it off at dealership. Attitude from service writer. Will take three days for diagnosis.

I think we're done with this. Are GM still buying back? I'll call and find out.

 

[balazer]

To those whose batteries were replaced after installation of the June 2023 Advanced Diagnostic Software (completion of recall N212345944), did you check your VIN in the GM warranty website some time later to see if a new "Bolt Battery Limited Part Warranty" was added? I noticed that for recall battery replacements, it could take 1-2 months for that to show up in the website. I'm trying to figure out if in fact no one is getting their warranties extended for these post-recall replacements.

 

[MichBolt]

...I noticed that for recall battery replacements, it could take 1-2 months for that to show up in the website. I'm trying to figure out if in fact no one is getting their warranties extended for these post-recall replacements.

It took almost a year for my updated warranty to show up.

 

[AdrianC]

Mine is going back to the shop again. Propulsion power reduced this morning.
No out of the ordinary use. Charged to 80% last night like normal.
Booked in for Monday morning. Will it be a third software update, or a third new battery, or both? lol.
I expect it just needs the new-new-new, less sensitive advanced diagnostics software.
Great car. GM software, not so much.

Edit: Just read the codes: U3636
Second edit: Just dropped it off at dealership. Attitude from service writer. Will take three days for diagnosis.

I think we're done with this. Are GM still buying back? I'll call and find out.

Result: Software update. Pick the car up tomorrow. Service writer said there was a bulletin.

I guess we’re all just unpaid beta testers for GM software.

 

[AdrianC]

From the dealer:

U3636, same as last time (original post in this thread). That time the solution was a new battery. This time the solution is just the software update. Still cost GM, but not as much this time!

Oh, we got the 100% charge version of the software.

 

[Just Me]

Here's the next chapter in my story. Got up yesterday morning to a flat tire. Argh! Fortunately, we have a compressor, so I was able to get it aired up and drove the 5-ish miles to the dealer. Got it all checked in and and the service rep provided an Uber home.
Middle of the afternoon, he calls and says, yes, the battery has a fault and GM will be getting me a new one. He said that the process for them to order a new battery has changed and mine is the first one for him with this process, so he's not sure about the wait time. For now, he's estimating 4 to 6 weeks.
He set me up with a rental through Enterprise, completely covered by GM. It turned out to be a brand new Volvo CX40 EV that they had just received!
Big sigh of relief!

Final chapter (I hope). Tuesday morning (8 days after dropping the car off) I get the call that the new battery is in and being installed! He said to pick up the next day because they want to do a full charge overnight. I dropped off the Volvo (which I enjoyed very much, but way overpriced I think), they took me to the dealer, picked up my baby and went on my way. Did my normal running around town yesterday and today and all is going well.
I see here that some folks are getting new batteries that are faulty. I'll check back in a couple of weeks and let you know how it's going after a couple of charges.

 

[BoltyMcFlatFace]

I am noticing that lots of people have only had the new BMS software (Instead of a new battery) for a short time before the U3636 Low Power (Not heat for me to clear my foggy windows). I had the software installed right after I bought the car in June, 1 day after GM stopped providing new batteries to all owners I have driven just over 6200 miles and should have been able to charge to 100%, but I let it get down to 10-15 miles range left and when I woke up it had only charged to 40%. I drove it 40+ miles to the dealer but being a Saturday they couldn't do anything. I tried to plug into their fast DC charger and it would only allow 4kw of charge rate. I left it there and am waiting for the big wigs at GM to decide what is needed. The car has 47k miles and is awesome. 2020 Premier. I don't have the details as I don't have the car. My one question for everyone who sees this that has this issue, how low did you let it get when this issue arose?