TSB 21-2091 - 12-Volt Battery Becomes Discharged While The Vehicle Is Plugged In During the High Voltage Charging Process

[generaltso]

No, the only OTA update we have gotten does NOT address this issue.

I assumed that was the case since the update only affected the gateway module. Hence my confusion.

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[GrumblesTheDog]

When do you think you can say you're out of the woods, regarding whether or not you'll fall victim to the 12V drain? My MME was built before 2/3, but on the later side (1/9). It has been fine despite fairly regular L2 charging over several hundred miles, though based on a handful of posts here it seems it can appear later on down the line when the conditions are right. It doesn't keep me up at night, but I do wonder. I have to make a road trip soon too, so maybe I'll make sure to have a portable jump pack (and/or 12V worth of AA batteries stuffed in the front bumper) just in case this strikes in the middle of nowhere.

 

[JSW]

When do you think you can say you're out of the woods, regarding whether or not you'll fall victim to the 12V drain? My MME was built before 2/3, but on the later side (1/9). It has been fine despite fairly regular L2 charging over several hundred miles, though based on a handful of posts here it seems it can appear later on down the line when the conditions are right. It doesn't keep me up at night, but I do wonder. I have to make a road trip soon too, so maybe I'll make sure to have a portable jump pack (and/or 12V worth of AA batteries stuffed in the front bumper) just in case this strikes in the middle of nowhere.

Days after I posted that I thought I was safe, bam! I found myself tearing apart my frunk. That said, I was leaving the MMe plugged into the charging station due to the cold MI temps and Ford’s advice. Turns out this was actually the problem - the MMe will charge the 12v battery on its own UNLESS you leave it plugged in.

Even if you’re part of the unlucky early build club, as long as you unplug your MMe after it is charged, you should be fine.

 

[shadowsjc]

Sticker on door sill will tell you the manufacture month and year. To find the exact day it has to be run through OASIS. Send me your VIN and I can get a build date for you.

Thanks - I checked the door sticker and it looks like Jan 2021. Guess I need to be careful and not charge to 100% until this gets sorted out.

 

[BMT1071]

Thanks - I checked the door sticker and it looks like Jan 2021. Guess I need to be careful and not charge to 100% until this gets sorted out.

Or you could make an appointment at your dealer to have the updates performed...

 

[AFVolt]

Or you could make an appointment at your dealer to have the updates performed...

I have some time off next week and scheduled the PAAK update. I specifically mentioned this update and was told the only one in their system is for the PAAK.

My MME has the early build date. How do I know this TSB doesn’t apply, since it includes the word “Some”?

How do I get the dealership to apply this? From what I understand none of the OTA updates I have gotten addressed this issue.

I have seen a few posts lately with people having no issue for thousands of miles, then all of a sudden having 12v issues.

Not addressing you directly BMT1071, you’re just the last one in this thread. ?

I’ve been relatively problem free for 6000 miles, but would hate to wake up one day to go to work with an unresponsive vehicle because I can’t get my dealership to apply an update that could have prevent the problem.

 

[Mach-Lee]

How do I get the dealership to apply this? From what I understand none of the OTA updates I have gotten addressed this issue.

I have seen a few posts lately with people having no issue for thousands of miles, then all of a sudden having 12v issues.

Not addressing you directly BMT1071, you’re just the last one in this thread. ?

I’ve been relatively problem free for 6000 miles, but would hate to wake up one day to go to work with an unresponsive vehicle because I can’t get my dealership to apply an update that could have prevent the problem.

You can only get warranty work done on problems your car currently has. So if your car doesn't have a 12V issue, the dealer cannot bill Ford for the warranty work. Those are just the rules.

If you want to offer to pay for the updates yourself proactively, knock yourself out. Probably an hour or two of labor, so a couple hundred bucks.

 

[benk016]

OK, I may have this issue. There have been a few times I've been in my car messing with OBD data, in the garage, plugged in not charging, and running in the ON position so the AC runs. But not ready because of being plugged in.

If I am in the car longer than 30 minutes I start getting all the error messages and alerts to service soon. Last night it happened and I checked and the 12v battery was at 8v.

The TSB stats when high voltage charging. Does that just mean anytime the car is plugged in? It definitely seems like in that state, the car is running things off the 12v battery and not doing any monitoring of the voltage.

 

[breeves002]

You can only get warranty work done on problems your car currently has. So if your car doesn't have a 12V issue, the dealer cannot bill Ford for the warranty work. Those are just the rules.

Technically this is true, BUT most dealers will apply updates if you have a related code without the symptom. If there is an SSM/TSB related to an update considering a specific code, they'll update based on that code. They just lie about it in the write up saying they witnessed the issue even though they most likely didn't and just pulled the code.

 

[Waps61]

OK, I may have this issue. There have been a few times I've been in my car messing with OBD data, in the garage, plugged in not charging, and running in the ON position so the AC runs. But not ready because of being plugged in.

If I am in the car longer than 30 minutes I start getting all the error messages and alerts to service soon. Last night it happened and I checked and the 12v battery was at 8v.

The TSB stats when high voltage charging. Does that just mean anytime the car is plugged in? It definitely seems like in that state, the car is running things off the 12v battery and not doing any monitoring of the voltage.

8Volts? Normally a 12V battery SOC below 11,5 V is considered deceased beyond revival. Are you sure you measured correctly?

 

[breeves002]

8Volts? Normally a 12V battery SOC below 11,5 V is considered deceased beyond revival. Are you sure you measured correctly?

11.5V is low, but not "deceased beyond revival". 12v batteries can easily hit 10.5v and still be revivable without serious damage.

 

[benk016]

the 8v is what the TCU was reporting it was running at. Unplugged and "started" the car and it jumped up to 13v

 

[Waps61]

11.5V is low, but not "deceased beyond revival". 12v batteries can easily hit 10.5v and still be revivable without serious damage.

I'm unaware of what type of 12V battery the MME has, but lead-acid batteries are dead when discharged below 10%=11.51V). AGM or Gell might possibly survive such a discharge when directly charged and topped of.

 

[ChasingCoral]

I'm unaware of what type of 12V battery the MME has, but lead-acid batteries are dead when discharged below 10%=11.51V). AGM or Gell might possibly survive such a discharge when directly charged and topped of.

The MME has an AGM 12v battery.

 

[benk016]

I'm unaware of what type of 12V battery the MME has, but lead-acid batteries are dead when discharged below 10%=11.51V). AGM or Gell might possibly survive such a discharge when directly charged and topped of.

Its possible that the low voltage was causing the modules to report weird numbers, and also why so many modules start throwing errors.

Its just odd that the high voltage is engaged, because the AC compressor is running, but, its not supplying any voltage to the 12v system in that state.

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