Another one bites the dust..

[h71]

Cruise set at 55, going up a small incline, 39 miles on the gom, yellow "!" lit up, followed by reduced power, then complete loss of power. Gom freaked out, reverted to full battery status and miles went to 3.. It's not the 12v. Disconnected 12v and letting it sit overnight, I'll try again tomorrow to charge it, but I already know...

 

[Randy960]

Sounds like a couple weak cells. You can clear the stored codes with the VCX Nano or an OBD scan tool with bidirectional control. That sort of sustained load cruising uphill is when they show up. With a Bluetooth OBD tool and Torque you can watch the individual cell voltages and see which ones are sagging under acceleration and the highest voltage while charging. My cells 80 and 81 are the worst. 16 and 49 aren't great either. My issues started at the end of summer, and I'm still commuting 30 miles a day, even in winter. In warmer weather I was still driving it further away and fast charging it, I just treated 20% as 0.

 

[h71]

Thanks, I'll check it out tomorrow. I have the torque app and setup, hopefully it can be brought back to life.

 

[RebamontanBeth]

Cruise set at 55, going up a small incline, 39 miles on the gom, yellow "!" lit up, followed by reduced power, then complete loss of power. Gom freaked out, reverted to full battery status and miles went to 3.. It's not the 12v. Disconnected 12v and letting it sit overnight, I'll try again tomorrow to charge it, but I already know...

I am going through the same thing with my mom’s spark. Were you able to find a solution?

 

[h71]

I am going through the same thing with my mom’s spark. Were you able to find a solution?

I haven't had a chance, Sparky went down last night. When it warms up a bit more outside I'll head out and connect the 12v battery and see if that reset anything. From what I have read from both Randy and other member posts the car likely has a bad cell or two that have fallen out of voltage with the rest of the pack cells and the pack has shut itself down as a result.

 

[Randy960]

This thread is from when I first had this issue, and I optimistically thought the 12v was the root cause.

Thread 'Died while driving due to 12v battery' https://www.mychevysparkev.com/threads/died-while-driving-due-to-12v-battery.9544/

This is when I upgraded my scan tool.

Post in thread 'My 2016 mod thread' https://www.mychevysparkev.com/threads/my-2016-mod-thread.9545/post-29872

 

[h71]

This thread is from when I first had this issue, and I optimistically thought the 12v was the root cause.

Thread 'Died while driving due to 12v battery' https://www.mychevysparkev.com/threads/died-while-driving-due-to-12v-battery.9544/

This is when I upgraded my scan tool.

Post in thread 'My 2016 mod thread' https://www.mychevysparkev.com/threads/my-2016-mod-thread.9545/post-29872

Thanks! I had a dealer do the official battery pack test last year before the battery warranty expired, which was 10 months back, they came back with 23% capacity loss, after using it for driving this winter it looks to be the end. With the pack crapping out with 2 bars over half and 39 miles on the gom, even if it can be un-bricked, that means this car is only capable 20 miles of range, it's 17 miles to work, add in heat or ac and the fact that charging there is impossible and this is the end for Sparky, it's too expensive to maintain tags and insurance for it to only be able to go around the neighborhood.

 

[Infinion]

Thanks! I had a dealer do the official battery pack test last year before the battery warranty expired, which was 10 months back, they came back with 23% capacity loss, after using it for driving this winter it looks to be the end. With the pack crapping out with 2 bars over half and 39 miles on the gom, even if it can be un-bricked, that means this car is only capable 20 miles of range, it's 17 miles to work, add in heat or ac and the fact that charging there is impossible and this is the end for Sparky, it's too expensive to maintain tags and insurance for it to only be able to go around the neighborhood.

The BMS is very unfriendly to drivers when it manages weak cells. It forces you to have dealer interactions which have tended towards buyback (usually under warranty) or whole battery replacements for an extremely unsustainable price point. Replacing 1 out of the 6 modules isn't a supported procedure for the dealer (3rd party only) and GMs part catalog has no module level searchable part numbers because that's not how they envisioned these cars would be supported...

I don't know if you have much experience pulling power out of with weak lithium cells, but it's often overlooked that in addition to the capacity loss, the ability to extract power quickly drops as well, which Randy pointed out drivers find out usually up hills and at or below 20-25%.

There are certain rules we've come up with to deal with the BMS's watchdog, which is what is killing off Sparks. That is the HPCM2 which the BMS reports this very specific event, and the HPCM2 maintains a hard to clear "do not resuscitate" error code. Did cells go through some irreversible damage? No. Is it dangerous to use again? No. Is it meant to be a nuisance? Absolutely.

A guide to avoid bricking your car due to weak cell freakout:

After losing your 3rd bar, as a driver, maintain a power limit on your cells. If you have 77% capacity remaining on 18.2kWh new packs, 1C (1x capacity) is about 14kW on the dash. This ensures maximum energy efficiency so slow chemistries can keep up and deliver power at their highest cell voltage, and at low states of charge (25% and lower). Throttling power ensures the individual cells are working above the watchdog's 2.5V freakout zone.
Outside of this range, it's safe to use more power, but be wary of how long you do it for because the chemistry will become tired and the voltage will sag, and usable energy will reduce for that discharge cycle.

Does that make sense? High efficiency is below 1-2C. Higher for the Spark EVs high discharge pouch type cells it should be 3-4C but weaker cells have lost the ability to discharge without dipping into low voltages that scare the sensitive watchdog computers. The degraded capacity can be fully extracted if drivers respect their limits.

You don't need to avoid driving under 20% but you should keep advanced scan tools on you and you should take care to work with these electrochemical cells. I'm sure the Bolt experiences this too, but they have 50-60kWh of capacity, so low power discharges are rather trivial.

 

[h71]

Thanks for the info, I don't have any diagnostic equipment past the torque pro app, which I still don't understand how to use, or how or where to get the bolt pid file. These app style scanners make absolutely no sense to me as I can't just dive into modules like a pro scan tool.

I have seen the mentions of resetting or clearing the hpmc2 unit but have no idea how to access it, what programs/permissions are required or anything else.

 

[Randy960]

This thread has a decent description of how to load the PIDs.

https://www.mychevysparkev.com/thre...fo-on-getting-torque-to-work.9284/#post-28533

 

[CSW]

So is this just something that happens to all Sparks at some point in time? If so, that sucks

 

[Randy960]

So is this just something that happens to all Sparks at some point in time? If so, that sucks

There's about a dozen reports of battery failures that fit this description, at least that I've come across on this forum. There's something like 7500 Spark EVs, and I really wish we had like a registry or something to see how many are still on the road. I can't tell from our small sample size if this is how they all eventually fail, or if only a percentage of them fail and this is how it seems to happen.

 

[h71]

Wasn't able to mess around with the car today as I got lost in finding out about vcx nano and what would be needed to get one and set it up for the car, looking into picking up a used unit from marketplace. I found my old phone still had the torque pro app still installed with the bolt pids from when the car was purchased a few years back, will check out the cell voltages tomorrow and follow up!

 

[h71]

Scanned with torque pro, I can't see any seriously low cells except for this group in the 40's (48-3.44v, 49-3.22), nothing like the 2.8v lows seen in other posts, however it's worth guessing that they may have gone below that when the error was first reported and have balanced out a bit from the other cells in the two days since the car was towed back..... Obd2 codes are:

-P0AFA OBD-II: Hybrid Battery System Voltage Low​

-P1E00- Command to engage check engine light, or the yellow "!"

-P0A7F OBD-II: Hybrid Battery Pack Deterioration​

 

[RebamontanBeth]

I haven't had a chance, Sparky went down last night. When it warms up a bit more outside I'll head out and connect the 12v battery and see if that reset anything. From what I have read from both Randy and other member posts the car likely has a bad cell or two that have fallen out of voltage with the rest of the pack cells and the pack has shut itself down as a result.

Thanks for the response. After lots of looking through these posts and messages with super helpful Randy, I’m waiting for my Autel scanner to arrive so I can try reset/clear any codes and crossing fingers, be able to charge again. Good luck with yours

 

[Infinion]

Scanned with torque pro, I can't see any seriously low cells except for this group in the 40's (48-3.44v, 49-3.22), nothing like the 2.8v lows seen in other posts, however it's worth guessing that they may have gone below that when the error was first reported and have balanced out a bit from the other cells in the two days since the car was towed back..... Obd2 codes are:

-P0AFA OBD-II: Hybrid Battery System Voltage Low​

-P1E00- Command to engage check engine light, or the yellow "!"

-P0A7F OBD-II: Hybrid Battery Pack Deterioration​

Don't forget the U0128 fault as a possible avenue to explore. I've gotten Powertrain faults accompanied by network faults like U0100 and U0073, although mine were recoverable anomalies. Yours specifically calls out the parking brake, but you could imagine for a moment that the parking brake and battery module share the same 2-wire communication bus through a wire harness. That 2-wire communication bus is like the nervous system of the car. It's not entirely redundant, so a loose connection could potentially mislead. For humans, imagine we get spinal damage from an accident and start having pain in our knees from a pinched nerve. That's referred pain and the solution would be to relieve that pinched nerve rather than fix the knee. Well I'm not saying that is the problem specifically in this case, but it's something to be mindful of if you're getting a parking brake fault. you could always check the wire harness around the parking brake module at the rear of the car for damage or looseness. If the spark is ever involved in an accident, just as an example, some wires could be crushed or insulation cut up, and you could get loss of signal from a short or open signal in the CAN or GMLAN communication lines.

Anyway just wanted to throw this in there when I noticed the network fault.

 

[Ziggy537]

My spark was stolen and I recovered it but not the how hard would it be to replace the ignition??

 

[FalconFour]

I do think this is something that'll happen to every Spark if you let it. The BMS is severely flawed and behaves unlike any other EV or device battery I've ever seen - not in any way that could rationally be considered correct or good. As batteries age, their cells will drift apart in capacity, and that's just a normal characteristic of batteries. But the BMS does absolutely nothing to react to it or provide a proper SOC% value... it'll just brick the battery if normal usage is performed to a normally-aging battery. It only monitors the cells and reacts to it by "bricking" the pack if the lowest-capacity cell goes to too low a voltage (as in: normal behavior when the pack is discharged).

My experience here:

My impressions of how it fails here:


I'm always open to counter-arguments, but because I bricked my battery while watching it fail... watching the voltages, in a perfect-timing alignment of the stars, ... I think I have a bit of a unique perspective. It was "easy" (time-wise) to unbrick it, but complex to piece it all together (software-wise).

My Spark has been happily back on the road (and burning tires, lol) like nothing happened. I'm also holding off on Part 2 (how to determine if your battery can be fixed) and Part 3 (how to fix it) as I'm meeting up with a poor soul I spotted on Facebook, whose car is held hostage at a Chevy dealer that basically refuses to fix it, refuses to let someone come fix it, and is asking to have the diag fees paid (to not fix it and give bad diag). Yeah, never go to Stewart Chevrolet in Colma, CA. But that should happen tomorrow afternoon... hopefully +1 more Spark back on the road

 

[Randy960]

Yeah, I think you about nailed it. I hadn't looked at r/sparkev much before, but it looks like a lot of bricked sparks over there.

I wonder how much of the BMS's... lax attitude about low cell voltage is due to how much the pack voltage sags under full load. I never watched the voltage before I started noticing issues, but watching now as I go full throttle with the battery at 100%, even the good cells dip into the low 3 volt range. I wonder if the BMS would be acceptable if the pack was like 30kwh+

 

[FalconFour]

I don't think it'd matter if the battery was larger. The pack would experience less overall C-rate stress, but the BMS flaw would still be present when the pack starts aging.

The biggest flaw in the BMS appears to be that it doesn't react to individual cell voltages - except to throw a "bricking" fault. The whole rest of the time, it just blithely ignores all individual cell voltages (except, maybe, to throw the "propulsion power reduced" warning - I haven't yet done a "scientific" test on that trigger point). One could say it considers "the average", but really that just means it's only reacting to a total pack voltage to display SOC% and capacity, "low battery" and shutoff, DC charging and driving power limits. Hell, it might even be using full pack voltage to show the "power reduced" warning.

In a properly designed BMS, the total pack voltage is nothing more than a trivia factoid. A piece of information that should be regarded as "oh, that's nice" that sits in its head, completely untouched by any logic. The pack voltage itself shouldn't matter to the BMS. It's a piece of information that's used by (and critical to) the operation of power electronics *outside* the BMS, but the BMS itself should never care about the total pack voltage. Its job is to care about the individual cells - the highest and lowest cells while charging and discharging, respectively. The total pack voltage would be a result of all the individual cells being within their constrained ranges, which would remain consistent solely if you simply track high/low cells.

So basically, the BMS doesn't do its job at all, which is truly quite shocking/appalling.

Yesterday, I successfully got another Spark EV on the road - clawed back from Stewart Chevrolet which stubbornly demanded $715 for two line items of "diagnosis" - one of which was a $125 charge (if I recall) for merely jump-starting the 12v battery so they could connect diagnostic tools. The 12v battery in that Spark was utterly dead* (drops to 5v the moment that support power is removed, even after over an hour at 14.4v), so we went to O'Reilly and got a replacement battery (steep, $255 - but knowing about the nuance of AGM, another poor choice on GM's part... we had to get it). Then headed over to an EVgo quick charger, got a friend to update its software so it could charge the Spark , and then got a quick charge and fully back on the road.



VCX Nano + Passthrough mode**
acdelcotds.com - Service Programming System (SPS2) license (one per VIN, we had to buy another $45 license to run it on this car)
A *clean* Windows laptop to run it on - TechLine Connect is hugely bloated and installs tons of software you don't want on your daily driver personal laptop
Have an EV charger ready (Level 1 or Level 2), powered up, no schedule, ready to plug in immediately.
A solid 14.4v power supply capable of outputting up to 15 amps for up to 1 hour (I used a large custom battery and an iCharger X12 in "DC supply" mode because... I'm a nerd and I make the best of the parts I have, haha)
Use SPS2 to do a "normal" reprogram on the HPCM2 (Hybrid Powertrain Control Module 2)***
IMMEDIATELY when the dash returns showing your battery at low charge (instead of "full" or "---" while reprogramming), do not sit around and look at what the laptop is doing, turn the car OFF and plug in the EV charger (J1772).

I'll try and turn this into a video soon. We did the above in a parking lot across the street from the dealer. I used V2L charging off my Model 3 to charge the car.

* - more damning to the dealer, really, because they should know that leaving a 12v battery dead and unmaintained will destroy the battery. So all told, the dealer probably killed/ruined that battery as well, by not having it out of the car and on a battery maintainer shelf, while they wait for service to proceed. I wonder how many lead batteries are killed by service centers a year...
** - VXDIAG has a weird website and odd bundled licensing with different prices. I believe "passthru mode" comes with *every* device regardless of which (GM, Ford, etc) you choose to purchase, but the different OEM brand models have different pricing. I don't understand it - but if you can buy one that offers *no* OEM license, that's just as well. You just need "passthru mode" for this. GM version is $109, https://www.vxdiagshop.com/wholesale/vxdiag-vcx-nano-for-gm-opel.html - but you might take a gamble and see if the Ford version works as well in passthru mode ($81): https://www.vxdiagshop.com/wholesale/vxdiag-vcx-nano-for-ford-mazda-2-in-1.html
*** - while I was doing this reprogram on this car, it appears the HPCM2 had already been reprogrammed, as the target version matched the current version and it didn't do the long reprogramming that happened on my car. That suggests the dealer already "tried" this, but didn't do the procedure correctly - they left it running with the battery in a totally-dead state, or tried to drive it, which immediately "bricked" it again. That's why immediately charging after unlocking is so important.