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We are not sure yet what the failure mode was on the modules. If it was just poor soldering as was suggested that is easy to fix. Parts are hard to come by currently and all it takes is one missing component for the module and it can't be built.
I would expect it is a latent manufacturing issue. The challenge to make more new BECMs would be chip availability, most likely... Though I did see somebody theorize some BECM vs. 12V battery system (bad 12V battery, low voltage, or 12V battery charger issues interacting with an overly sensitive BECM) as a possible cause of BECM failures which would be interesting.

-Charlie
 

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I would expect it is a latent manufacturing issue. The challenge to make more new BECMs would be chip availability, most likely... Though I did see somebody theorize some BECM vs. 12V battery system (bad 12V battery, low voltage, or 12V battery charger issues interacting with an overly sensitive BECM) as a possible cause of BECM failures which would be interesting.

-Charlie
My BECM failure moments happened on extreme cold days, and I did have slightly low 12V battery voltage, which made me assume the problem was just the 12V getting old. From what I've read, cold brings out the BECM issues because of the solder contracting, but it'd be interesting if it had to do with 12V battery interactions (ex. BECM having to function outside of its parameters in some way to compensate for 12V battery condition).
 

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My BECM failure moments happened on extreme cold days, and I did have slightly low 12V battery voltage, which made me assume the problem was just the 12V getting old. From what I've read, cold brings out the BECM issues because of the solder contracting, but it'd be interesting if it had to do with 12V battery interactions (ex. BECM having to function outside of its parameters in some way to compensate for 12V battery condition).
I just got mine repaired after a 50-day wait. Yay!

I measured a direct correlation between 12v rail voltage and BECM anomalies.
Mine also manifested first in cold weather with the original battery. It wasn't bad, just not super fresh.

I also found a workaround to drive reliably with a flaky BECM:
(at least it didn't fail on ME. YMMV :)

  • Keep headlights ON while driving (this keeps 13.7v on 12v rail and doesn't let the 12v battery float).
  • Disconnect -12v lead for overnight or longer storage (to not further cook the electronics while waiting for replacement).
  • Do not charge past ~75% SOC, unless travelling immediately after charge. (BECM seemed more flaky at 100% SOC, perhaps using more current to balance full cells?)
  • Connect quality battery maintainer to 12v battery while car is not in use. I crafted a little notched-wood block thingy that I could rest the hatchback on so that the cord wouldn't deform the seal.

In this way, with Headlights-ON, I was able to drive without fail. Sometimes I'd park and come back and I'd see 1 mile on the Guessometer and it would start counting up to the actual miles and I'd be good to go.

Before I discovered the healights-ON workaround, I found that Reduced Propulsion Mode charges the 12v battery with almost 15v so I could run in RPM for a few minutes, then, turn the car OFF, and then on again, and the Guessometer will count up the traction battery miles.
I also used my GooLoo 4000 boost pack, which does 15v, to boost the 12v battery enough so that the BECM was happy.

FWIW, immediately after the warranty diagnosis, I installed a brand-new and fully-charged 12v battery.
At first, I thought I fixed it, but a few hours later, it happened again.

Hoping this info helps someone not have to get towed.

Some say the problem is cracked traces or solder joints. I'm not so sure.
In my experience with electronics, always-on electronics fail sooner than not-always-on counterparts. AFAIK, The BECM is always-on, or at least has sections that are.
It is well-known that semiconductor atoms can slowly migrate across transistor junctions over time, and eventually cause the junction to fail.
I have seen printer network-interfaces-cards fail well before the printer, because the NIC needs to remain always-ON and cannot sleep like the printer can. Replace the NIC, and the printer is happy again.
Those are just my observations and conjecture. :)
 

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I hope everyone contacts the NHTSA about this problem. Should be a recall. My 2017 appears to have the same issue with the BECM but it has gotten worse. Had to disconnect 12V battery cable because there is an 8 amp parasitic drain on 12V battery with vehicle off, all doors closed and fob not anywhere near the car. Concerned that vehicle will catch fire with that large a drain, possible dangerous short.
 

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Greetings!

My 2017 Volt is dead too due to BECM problem. It's about 42k miles on it.

Does someone know if the Voltec warranty covers vehicles outside US and Canada?

As for 12V battery influence, maybe changing it to LiFePo4 battery will do the thing? Weight reduction as a bonus.
 

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Greetings!

My 2017 Volt is dead too due to BECM problem. It's about 42k miles on it.

Does someone know if the Voltec warranty covers vehicles outside US and Canada?

As for 12V battery influence, maybe changing it to LiFePo4 battery will do the thing? Weight reduction as a bonus.
If you're trying to keep under warranty, I'd stick to something close to OEM 12V so that you're not opening a door for a warranty denial.
 

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I checked into the Dead BECM club on here on page 8 (#153) at the end of January. I finally got the call that my replacement BECM had arrived at the dealership on 4/25. I got my car back on 4/29...so, roughly three months total without the Volt...though I did talk them into letting me keep it in my own garage while waiting for the part.

A couple of days ago, I had just gotten back from dropping my other DD, a '17 Malibu Hybrid, at the same dealer to have the 19-NA-206 Shift-To-Park repair issue addressed. Pulling into my garage, the Volt flashed Shift-To-Park as well! So, all in the family, heh? Go, GM!
 
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Stands to reason if a faulty micro switch is used in more than one car, they can both experience a problem. Other's have repaired their own for a few dollars and some time.
 

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Stands to reason if a faulty micro switch is used in more than one car, they can both experience a problem. Other's have repaired their own for a few dollars and some time.
The base mechanism is the same in a bunch of GM vehicles - just different trim/knobs snapped on the top.

-Charlie
 
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