Anatomy of a 12V Fault-Service with OTA Ford Power-Up 2.1.0

louibluey · Jan 11, 2022

Monitoring the BMS (device on the negative terminal of the 12V LVB), I happened to get a first record before a 12V Fault - service Fordpass message. By luck, I got an OTA event at the same time (Ford Power-Up 2.1.0).

Probably best if I explain events first, fortunately with Ring camera in the garage, I was able to reconstruct my activities:
1:13 pm unplugged L2, moved car into driveway (needed to get a ladder out for clearing solar panels, generally a complete waste of time in Jan., but good exercise)
1:49 pm MME back in garage, plugged into L2
5:10 - 512 pm, Fordpass has been complaining that I have updates turned off, so I relented, checked WIFI, enabled OTA updates.
7:05 pm, opened MME to get my eyeglasses which were left in car
7:11 pm, got FordPass alert, Jan 10, 2022, 07:11 PM, There's an issue ... 12V battery ... service soon
8:24 pm, reset LIN monitor to end old record and begin a new file (the old file was getting large, about 54 hours garage, plugged in L2)

Graphs are 12V LVB voltage over LVB % soc, horizontal axis time in decimal hours. The break between the two graphs is about 8:24 pm, Jan 10. The alert was about hour 13 to the left of the break (1st graph).

So this is only one sample, but still interesting. On the first graph, around 7 hours is the first unplug, the beginning of that that third vertical line (DC/DC converter on) probably the 1:49 L2 plug in. The spike around 11 hours is turning on OTA, 13 hours where I got my eyeglasses out of the car, which lights load caused MME to seriously start charging LVB.

The subtle but interesting part is after OTA started, note a number of small dips in voltage, just before I retrieved my glasses. The discharge slope is slightly steeper after 5:10 pm, presumably the OTA activity. No idea on the exact timing of OTA download vs. install, perhaps that 3am event was the actual update?

soc dropped to 34% (just for an instant) which apparently triggered the service warning.

The second graph shows LVB doing fine all night once, charged. Chargepoint graphs at the end, first one to 11 pm, second to 9am this morning showing that 3 am LVB maintenance (I think low 20's Jan 10 afternoon, -6F by early morning Jan 11, unheated garage).

AFAIK, my MME was already up to date by manual FDRS updates, not sure why it insisted on checking off the OTA event, but who was I to argue?

Ford Mustang Mach-E Anatomy of a 12V Fault-Service with OTA Ford Power-Up 2.1.0 both

Ford Mustang Mach-E Anatomy of a 12V Fault-Service with OTA Ford Power-Up 2.1.0 Jan 10 MME 2pm to 11pm

Ford Mustang Mach-E Anatomy of a 12V Fault-Service with OTA Ford Power-Up 2.1.0 Jan 10 MME 2pm to Jan 11 9am

Ford Mustang Mach-E Anatomy of a 12V Fault-Service with OTA Ford Power-Up 2.1.0 Screen Shot 2022-01-11 at 2.34.52 PM

Ford Mustang Mach-E Anatomy of a 12V Fault-Service with OTA Ford Power-Up 2.1.0 Screen Shot 2022-01-11 at 2.35.06 PM

Murse-In-Airy · Jan 11, 2022

You’re way over my head here @louibluey But I think you’re saying too many things drew the 12V battery down and you got a 12V fault. But not THE 12 V fault that requires being towed to the dealer. So did the HVB kick in and charge the 12V? Or did you have to go put a charger on it?

TAPe · Jan 11, 2022

I had the 12v battery fault - service soon happen Saturday afternoon when I parked the car in my garage after running a few errands. While running around I noticed a download icon so I checked the Sync and the 2.3 had just loaded. This was approximately 30 minutes before the 12v fault warning. The soc% was approximately 90% at the time. All of this may be purely coincidental. The car is scheduled to be checked out next Monday morning. I have no indication by any warning light that the 12 volt battery is low. Since it’s so cold, I keep the car plugged in whenever it is in our garage which is every evening.

louibluey · Jan 11, 2022

Murse-In-Airy said:
You’re way over my head here @louibluey But I think you’re saying too many things drew the 12V battery down and you got a 12V fault. But not THE 12 V fault that requires being towed to the dealer. So did the HVB kick in and charge the 12V? Or did you have to go put a charger on it?

It charged itself, just plugged into L2.

The top voltage graph is what you would see with one of those 12V accessory port (lighter) plug in monitors, but they stop working some time after MME is off. This monitor runs 24/7, but the BMS module on the battery reports fast when awake (25 times / second) and slow when sleeping, wakes up every 15 minutes and reports (why some dots are so widely spaced (MME REM sleep)).

On that top graph, anything say about 11.9V to 13.1V is battery terminal voltage, the higher readings 13.4V to 15.6V are all showing that the DC/DC converter running. When it's cold, MME seems to just put the DC/DC converter "full on" at 15.6V.

When MME is resting (all lights off), the battery is more lightly loaded, and the voltage goes up a couple to few tenths of a volt. Probably, when I unlocked it and opened the door (7 pm to get my glasses), the lights that came on dropped the voltage, so MME thought the soc had dropped low enough to start some serious LVB charging, which it did for over an hour to bring the soc back to 90% (which is great). Unclear why MME set off the service warning, especially because 2 hours later, everything was fine, good as new. So, I'm going to call this 12V service warning bogus.

louibluey · Jan 11, 2022

TAPe said:
I had the 12v battery fault - service soon happen Saturday afternoon when I parked the car in my garage after running a few errands. While running around I noticed a download icon so I checked the Sync and the 2.3 had just loaded. This was approximately 30 minutes before the 12v fault warning. The soc% was approximately 90% at the time. All of this may be purely coincidental. The car is scheduled to be checked out next Monday morning. I have no indication by any warning light that the 12 volt battery is low. Since it’s so cold, I keep the car plugged in whenever it is in our garage which is every evening.

I think what is happening with most of these warnings (TBD) is just normal discharge / charging. For some reason, what the algorithm allows for low voltage and/or soc before doing an extended 1+ hour LVB charging, is also setting off the warning. It might be as simple as unlocking, where the loads and lights that come on drop the LVB measured voltage by .2 to .4 volts, which triggers the service warning.

So, in your report, possibly your warning was earlier, maybe when you began the drive home, and by the time you were in the garage, soc was already charged back to 90%?

That said, clearly some LVB problems are different where there is a dead LVB, or possibly (?) some of the while driving problems are LVB related, different situations entirely (I think).

Murse-In-Airy · Jan 11, 2022

Gotcha. So this is the kind of 12V battery warning people are freaking out about while the car is getting ceramic coated or tinted. Nothing to worry about. Just an alarmist warning. I agree, why not have the car just shut its mouth and do its job, charge the 12V from the HVB like it’s supposed to. Stupid car.

AMJ · Jan 11, 2022

I have had four 12v battery fault notices. First one was mid November, (shortly after I picked up my new car for the first time,) when I had dropped it off to have PPF done. Second time was about 3 weeks later while the car was being ceramic coated. Third time was just after Christmas while car was just sitting in garage, and plugged in. Fourth time was this past Sunday afternoon, 1-9-22, again while car was just sitting in garage plugged in. Took it to the dealer today. Battery tested fine, and nothing wrong with it. They are doing updates to the car and that should hopefully end these erroneous notifications. I do find it odd that notices others have gotten match the same day, or almost the days as mine. Just weird.

louibluey · Jan 11, 2022

AMJ said:
I have had four 12v battery fault notices. First one was mid November, (shortly after I picked up my new car for the first time,) when I had dropped it off to have PPF done. Second time was about 3 weeks later while the car was being ceramic coated. Third time was just after Christmas while car was just sitting in garage, and plugged in. Fourth time was this past Sunday afternoon, 1-9-22, again while car was just sitting in garage plugged in. Took it to the dealer today. Battery tested fine, and nothing wrong with it. They are doing updates to the car and that should hopefully end these erroneous notifications. I do find it odd that notices others have gotten match the same day, or almost the days as mine. Just weird.

My guess is the warnings are individual MME generated, but nothing is certain. Let's post either here, or to a new thread when we get a 12V warning. That would be pretty funny if they all happen on the same day!

EricTheRed44 · Jan 12, 2022

Just to add my 12v fault to the list. I happened on Sunday 1/9/22. The car was not plugged in overnight, it was freezing when I moved the car back into the garage "12v fault service soon" on the screen. Plugged in. I haven't been back into the car since. I will check this weekend.

jeffdawgfan · Jan 23, 2022

I got this warning for first time yesterday right after washing the car at home. Moved car back into garage and plugged in to charge for a trip we are making tomorrow. Got the warning over my phone. I have never had the warning before. Of note, I did take car to dealer to get all dealer applied updates last Monday....coincidence??? This morning there was no warning after charging.

louibluey · Jan 23, 2022

jeffdawgfan said:
I got this warning for first time yesterday right after washing the car at home. Moved car back into garage and plugged in to charge for a trip we are making tomorrow. Got the warning over my phone. I have never had the warning before. Of note, I did take car to dealer to get all dealer applied updates last Monday....coincidence??? This morning there was no warning after charging.

MME / Fordpass seems to make the 12V service warning when it charges LVB from around 40% soc, so probably when you moved the car and plugged in, either one of those events started the DC/DC converter, and generated the warning when it started charging LVB.

AMJ · Jan 23, 2022

AMJ said:
I have had four 12v battery fault notices. First one was mid November, (shortly after I picked up my new car for the first time,) when I had dropped it off to have PPF done. Second time was about 3 weeks later while the car was being ceramic coated. Third time was just after Christmas while car was just sitting in garage, and plugged in. Fourth time was this past Sunday afternoon, 1-9-22, again while car was just sitting in garage plugged in. Took it to the dealer today. Battery tested fine, and nothing wrong with it. They are doing updates to the car and that should hopefully end these erroneous notifications. I do find it odd that notices others have gotten match the same day, or almost the days as mine. Just weird.

Since I first posted this I have gotten two more 12V Battery fault notices. One on Sunday, January 16th, and again on Friday, January 21st. I have no idea why. Car had not been driven either of those days, and was sitting in garage plugged in. I did post in one of the Facebook groups about my notices and received this reply which I found very interesting and informative. I think this may be the scenario in a lot of these 12v Battery fault notices. This is the reply:
I have to be very careful here ... because this is not a "one answer is correct for all situations" thing.
I *also* had the 12v error pop up on my car back in December -- just a few days before I was heading out from Michigan to Florida and back. So I was a little worried about starting a drive of a couple thousand miles where I might be stranded.
But fortunately I have managed to establish some contacts at Ford Motor Company (engineers). They pulled the logs from my car. What they found ... was that the 12v battery had managed to get low enough that it needed a charge. The logs ALSO showed that the car did exactly what it is programmed to do ... it started charging the 12v battery. What they DO NOT know ... is *why* it bothered to send me a battery low alert. This is something the car would have been expected to do if the battery got too low and wouldn't have been able to charge. But it DID charge ... and the car was fine. I did the trip and had absolutely no issues. The battery checks out fine.
My guess is that there is a software logic bug resulting in the car sending the alert even though nothing is wrong. Since Ford knows about the issue ... my guess is that there will be a software update that fixes it.
It doesn't appear to be an *actual* problem with the car.
The reason I said I have to be careful ... is because it's possible someone has a 12v battery that is actually having a problem ... and I'd expect they would also get this error. For this reason I don't recommend you just ignore it and dismiss it as a software bug.
I bought a USB charger that plugs into the 12v cigarette lighter outlet (in the storage bin below the armrest) ... but the model I bought has a voltmeter on it. When the car is "on" it will typically read 15v (because the high voltage battery is connected). But when the car is "off" it will read the true voltage. You can get one of these (there are literally dozens and dozens of them offered on Amazon) and read the voltage in the cigarette lighter when the car is "off". That should give you a better idea of the battery state.

louibluey · Jan 23, 2022

AMJ said:
Since I first posted this I have gotten two more 12V Battery fault notices. One on Sunday, January 16th, and again on Friday, January 21st. I have no idea why. Car had not been driven either of those days, and was sitting in garage plugged in. I did post in one of the Facebook groups about my notices and received this reply which I found very interesting and informative. I think this may be the scenario in a lot of these 12v Battery fault notices. This is the reply:
I have to be very careful here ... because this is not a "one answer is correct for all situations" thing.
I *also* had the 12v error pop up on my car back in December -- just a few days before I was heading out from Michigan to Florida and back. So I was a little worried about starting a drive of a couple thousand miles where I might be stranded.
But fortunately I have managed to establish some contacts at Ford Motor Company (engineers). They pulled the logs from my car. What they found ... was that the 12v battery had managed to get low enough that it needed a charge. The logs ALSO showed that the car did exactly what it is programmed to do ... it started charging the 12v battery. What they DO NOT know ... is *why* it bothered to send me a battery low alert. This is something the car would have been expected to do if the battery got too low and wouldn't have been able to charge. But it DID charge ... and the car was fine. I did the trip and had absolutely no issues. The battery checks out fine.
My guess is that there is a software logic bug resulting in the car sending the alert even though nothing is wrong. Since Ford knows about the issue ... my guess is that there will be a software update that fixes it.
It doesn't appear to be an *actual* problem with the car.
The reason I said I have to be careful ... is because it's possible someone has a 12v battery that is actually having a problem ... and I'd expect they would also get this error. For this reason I don't recommend you just ignore it and dismiss it as a software bug.
I bought a USB charger that plugs into the 12v cigarette lighter outlet (in the storage bin below the armrest) ... but the model I bought has a voltmeter on it. When the car is "on" it will typically read 15v (because the high voltage battery is connected). But when the car is "off" it will read the true voltage. You can get one of these (there are literally dozens and dozens of them offered on Amazon) and read the voltage in the cigarette lighter when the car is "off". That should give you a better idea of the battery state.

This is what several of us are seeing, MME detects the need to charge LVB and does so. In some conditions, it waits until a 12V battery soc of 35% to 40%. At about the same time MME turns on the DC/DC converter to charge the 12V battery, it seems to trigger a time stamped Fordpass notice (the notice might arrive later) that 12V service is needed.

AMJ · Jan 25, 2022

AMJ said:
I have had four 12v battery fault notices. First one was mid November, (shortly after I picked up my new car for the first time,) when I had dropped it off to have PPF done. Second time was about 3 weeks later while the car was being ceramic coated. Third time was just after Christmas while car was just sitting in garage, and plugged in. Fourth time was this past Sunday afternoon, 1-9-22, again while car was just sitting in garage plugged in. Took it to the dealer today. Battery tested fine, and nothing wrong with it. They are doing updates to the car and that should hopefully end these erroneous notifications. I do find it odd that notices others have gotten match the same day, or almost the days as mine. Just weird.

Had my car at the dealership today. This is the bulletin they got regarding the 12v Battery Fault messages. An OTA is supposed to come out in a couple of months. I sure hope that fixes these erroneous messages. The battery still tests as good. I have never noticed the IPC being on after the car has been turned off. But it's possible as I don't spend anytime in the garage.

Ford Mustang Mach-E Anatomy of a 12V Fault-Service with OTA Ford Power-Up 2.1.0 272742016_10222049434930538_7307636388634646846_n

JimmyMachE · Jan 26, 2022

Shall we all carry out this procedure - turn on hazard lights for 3 flashes, just in case?

Anatomy of a 12V Fault-Service with OTA Ford Power-Up 2.1.0

louibluey

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