[superduper]

I was driving last night, suddenly got a notice that power to drivetrain was lost as the truck stopped moving. Then, the battery charge went from ~50% to almost 0%. Flashed all sorts of warnings like "Service High Voltage System" and "Conditions not proper to shift" (into gear).

Has anyone experienced anything similar? I sure hope this isn't the start of a series of Chevy Volt-esque issues for the Hummer EV line.

 

[INgolfer]

Yikes! Glad it disnt cause you to crash! Based on some of the problems we are seeing here with so few Hummers on the road I definitely wouldn’t want to be one of the people buying a Hummer from a flipper and losing my warranty

 

[Nebula1701]

Sounds like the Truck lost communication to the BECM modules or something happened to the 12V.

Did the truck perform normally after a restart or did it have to be towed?

Checking your post history, you complained about a battery fault before... Did that actually happen? You have so few posts here.

 

[Tom E-Tron]

Sounds like the Truck lost communication to the BECM modules or something happened to the 12V.

Did the truck perform normally after a restart or did it have to be towed?

Checking your post history, you complained about a battery fault before... Did that actually happen? You have so few posts here.

Ya, that is odd. Considering the post history my FUD alarm bells are ringing, I sure would like to see pictures of those error messages.

 

[TRider86]

As far as I know per TAC. Only 1 Hummer has needed a battery pack replacement due to internal communication error. Maybe yours? I have the first loss of isolation they have seen currently. FSE is supposed to be in Monday for us to rip into it. (GM wont let us touch it without an Engineer there apparently). Could be possibly second battery pack replacement.

if you truly have a battery issue, you’d possibly be only the 2nd or 3rd in the country. No need to throw out the idea that its the second coming of Bolt issues quite yet

 

[Amgman1]

As far as I know per TAC. Only 1 Hummer has needed a battery pack replacement due to internal communication error. Maybe yours? I have the first loss of isolation they have seen currently. FSE is supposed to be in Monday for us to rip into it. (GM wont let us touch it without an Engineer there apparently). Could be possibly second battery pack replacement.

if you truly have a battery issue, you’d possibly be only the 2nd or 3rd in the country. No need to throw out the idea that its the second coming of Bolt issues quite yet

My truck is in the shop right now for similar issue. High-voltage lithium battery warnings. Truck made it home but apparently the fans to cool the batteries weren’t turning on. That’s what they’ve told me so far. Waiting on an engineer to show up

 

[Tom E-Tron]

My truck is in the shop right now for similar issue. High-voltage lithium battery warnings. Truck made it home but apparently the fans to cool the batteries weren’t turning on. That’s what they’ve told me so far. Waiting on an engineer to show up

I have only heard my fans run while fast charging, other times no sound that I have noticed

 

[TRider86]

My truck is in the shop right now for similar issue. High-voltage lithium battery warnings. Truck made it home but apparently the fans to cool the batteries weren’t turning on. That’s what they’ve told me so far. Waiting on an engineer to show up

I’d be very interested to see what they figure out!

 

[ofaridi32]

I've had 12 Volt battery issues 3 times now. The Hummer has been in the shop for about 31 days this last time (2 weeks were because the tow company damaged the hood and hooks that needed to be repaired). They've sent a GM tech out twice; this time did a "global reset" and apparently solved the problem that was "draining" the battery (I know this has happened to others). But when it came back from the body shop. apparently a "connector" was loose (the female portion vs the male portion) on some module.... and the dealership did not have the "part" to remove the loose part and replace the female connector- so now GM is sending the part to them and a field tech again... going on 40 days without my car now...... this is getting ridiculous... close to "lemon lawing" this thing in California .. or at least looking into it. They swear this is the last time and everything will be ok... so probably giving them one more chance. But in 3 months; its been in the shop 3 times; each time for over a week and this time for 30+ days!

 

[Nebula1701]

Seriously when you buy a early release vehicle you should be expecting early adopter issues. There are very few Hummers out there and the techs at the dealerships are still learning about these vehicles, not to mention parts will be limited for some time.

 

[ofaridi32]

Seriously when you buy a early release vehicle you should be expecting early adopter issues. There are very few Hummers out there and the techs at the dealerships are still learning about these vehicles, not to mention parts will be limited for some time.

I agree and understand... but at some point it may be excessive... I was one of the first guys to get a Taycan when it came out.... had some charging issues... was in the shop a few days multiple times.. but didn't seem as much as this... and the GM guys seem to be a lot more clueless about how to diagnose/fix... they haven't given me a clear answer to what the problem has been each time... and I can only ask so many times/ways ... weird situation. Also have had multiple Tesla's... multiple minor issues..... but hey... when the Hummer is working... I love it... so I'm willing to give them a little more lee-way.... but 40 days straight in the shop when I only took delivery 3 months ago... its starting to wear on me..... and this is the 3rd time ... it seems to be ok only 7 days at a time... then something pops up. Then I take it to the dealer... they let it sit there for days until GM gets all the diagnostic info and then few days later tells them what to do. or if I'm lucky they send a GM tech out... which takes another week or so... and I drive a Terrain loaner in the meantime.....

 

[Tom E-Tron]

I agree and understand... but at some point it may be excessive... I was one of the first guys to get a Taycan when it came out.... had some charging issues... was in the shop a few days multiple times.. but didn't seem as much as this... and the GM guys seem to be a lot more clueless about how to diagnose/fix... they haven't given me a clear answer to what the problem has been each time... and I can only ask so many times/ways ... weird situation. Also have had multiple Tesla's... multiple minor issues..... but hey... when the Hummer is working... I love it... so I'm willing to give them a little more lee-way.... but 40 days straight in the shop when I only took delivery 3 months ago... its starting to wear on me..... and this is the 3rd time ... it seems to be ok only 7 days at a time... then something pops up. Then I take it to the dealer... they let it sit there for days until GM gets all the diagnostic info and then few days later tells them what to do. or if I'm lucky they send a GM tech out... which takes another week or so... and I drive a Terrain loaner in the meantime.....

No doubt the number of Hummer problems so far are excessive, and GM is learning their way through this, unfortunately when you pull a program ahead in development there is no way to avoid this. GM using the Hummer program and us as a pathfinder to work out the bugs, Silverado launch should be smoother

 

[Dark-Fx]

No doubt the number of Hummer problems so far are excessive, and GM is learning their way through this, unfortunately when you pull a program ahead in development there is no way to avoid this. GM using the Hummer program and us as a pathfinder to work out the bugs, Silverado launch should be smoother

I'm sure it's the reason they are doing the NDA and discount for the earliest lyriqs. Another new platform that was pulled way ahead.

It's probably also why my dealer wasn't letting me bring the truck in until they were actually ready to work on it. Of course I didn't have any issues that truly affected driveability. If my truck had a 12V issue, I would have been hanging a solar trickle charger off of it while still driving it and waiting for them to be ready.

 

[ofaridi32]

Haha right before I’m about to go pick up my truck again the 12V dies… 5th time now. Almost 40 days straight in the shop. Sending a GM “engineer” again to try and figure it out… is there a running list on diffeu reasons for the draining of the battery? Because they can’t figure out why it keeps happening

 

[Dark-Fx]

Haha right before I’m about to go pick up my truck again the 12V dies… 5th time now. Almost 40 days straight in the shop. Sending a GM “engineer” again to try and figure it out… is there a running list on diffeu reasons for the draining of the battery? Because they can’t figure out why it keeps happening

There is probably a module that isn't going to sleep when it's told to and is keeping the bus awake, leading to it draining the 12V battery because the HV battery still gets disconnected and the truck won't charge the 12V while it's disconnected. Diagnosing that sort of an issue would be a pain in the ass without very specialized tools.

 

[Snogoer]

There is probably a module that isn't going to sleep when it's told to and is keeping the bus awake, leading to it draining the 12V battery because the HV battery still gets disconnected and the truck won't charge the 12V while it's disconnected.

I had one 12V issue...died after it was parked for 6 days. Dealer said there was a module that wasn't shutting down and it drained the battery. Isolated the problem, did a couple software updates and no 12V problems since.

 

[Nebula1701]

I had one 12V issue...died after it was parked for 6 days. Dealer said there was a module that wasn't shutting down and it drained the battery. Isolated the problem, did a couple software updates and no 12V problems since.

Guess ofaridi32's dealership needs to talk to yours then.

 

[INgolfer]

I had one 12V issue...died after it was parked for 6 days. Dealer said there was a module that wasn't shutting down and it drained the battery. Isolated the problem, did a couple software updates and no 12V problems since.

This is one thing I am worried about as I travel a lot for work, so I’ll be driving my Hummer to the airport and leaving it there for 4-5 days at a time. I’d hate to get back and have the 12V drained. Hope they figure out what the problems are soon and push out a software update to prevent them from draining

 

[Dark-Fx]

This is one thing I am worried about as I travel a lot for work, so I’ll be driving my Hummer to the airport and leaving it there for 4-5 days at a time. I’d hate to get back and have the 12V drained. Hope they figure out what the problems are soon and push out a software update to prevent them from draining

12V issues were quite prevalent early on with the Polestar 2. A lot of people on the forums carry jumper packs. I've never bothered to for any vehicle yet.

 

[Shaved Ice]

12V issues were quite prevalent early on with the Polestar 2. A lot of people on the forums carry jumper packs. I've never bothered to for any vehicle yet.

I only have one as it was in my Jeep previously. Easier than jumping from one vehicle to another.