Low 12V battery voltage caused some peculiar software gore

[ctuan13]

So although I've otherwise had zero issues with my Lightning, I've had a persistent 12V battery draining issue that results in the truck going into deep sleep after at most three days sitting idle.

With the cold weather I experienced some peculiar issues yesterday. After driving and parking at my destination for four hours, when I got back to the truck it was clearly in "deep sleep". No approach lighting, screens dark upon opening the door and chime only emitting from dash speaker on startup.

But the weirdest issues took a minute or two of driving before I actually noticed. The icon for the settings menu was displaying a white Mach-E even after forcing a reboot on the Sync system (pictured below) and the GOM was wildly inaccurate with the number rising and falling by several miles every 10-15 seconds (didn't manage to get a picture or video of this) and the percentage seemed to be falling alarmingly fast (ie somewhere around 15% in 5 minutes of highway driving.

So I pulled over and disconnected the 12V battery for a minute, reconnected and this solved the issues, but still annoying to have repeated 12V battery issues, though this is the first time I've experienced this sort of major glitch, usually the only symptom is a persistent "deep sleep" that persists through several key cycles.

Maybe something to do with the 3.8.4 update?

Any of you guys experienced this?

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[Lightning Rod]

Is your 12 volt battery up to proper charge? That is weird that unplugging the 12v battery "fixed" the problem. I would make sure the battery is at adequate voltage and also see if you have something that is draining your 12v battery. I would just take it to your dealer and have him look at it under the warranty.

 

[ctuan13]

Is your 12 volt battery up to proper charge? That is weird that unplugging the 12v battery "fixed" the problem. I would make sure the battery is at adequate voltage and also see if you have something that is draining your 12v battery. I would just take it to your dealer and have him look at it under the warranty.

Well at that point it wasn't up to perfect charge (I was monitoring the 12v battery parameters using an OBDII dongle) but it charges up normally during a drive and sometimes when I can ill throw a charger on it when I plan to park it for more than a day or so.

But it's odd because definitely, I can see using the wireless OBDII dongle that often after shutting off the truck, there continues to be a draw on the battery. It starts at 25A, then drops to 20A, then 16A, then 11A and finally after 15 minutes it'll drop to 6A, but it never seems to cease entirely or at least not while I'm monitoring it. But obviously while charging the main battery pack, the DC-DC converter is charging the 12V and also while the truck is on.

What's interesting is that even though initially thought it was just some sort of failed component static parasitic draw. If I disconnect and reconnect the 12V battery, the parasitic draw dissapears...at least until I open a door or start and shut off the truck.

But yeah I guess I'll have to bring it to a dealer at some point. Just odd because despite other incidents of 12V battery issues, I've never experienced a software glitch quite like that!

 

[Lightning Rod]

Well at that point it wasn't up to perfect charge (I was monitoring the 12v battery parameters using an OBDII dongle) but it charges up normally during a drive and sometimes when I can ill throw a charger on it when I plan to park it for more than a day or so.

But it's odd because definitely, I can see using the wireless OBDII dongle that often after shutting off the truck, there continues to be a draw on the battery. It starts at 25A, then drops to 20A, then 16A, then 11A and finally after 15 minutes it'll drop to 6A, but it never seems to cease entirely or at least not while I'm monitoring it. But obviously while charging the main battery pack, the DC-DC converter is charging the 12V and also while the truck is on.

What's interesting is that even though initially thought it was just some sort of failed component static parasitic draw. If I disconnect and reconnect the 12V battery, the parasitic draw dissapears...at least until I open a door or start and shut off the truck.

But yeah I guess I'll have to bring it to a dealer at some point. Just odd because despite other incidents of 12V battery issues, I've never experienced a software glitch quite like that!

Yes. That constant draw is coming from somewhere. I would definitely let the dealer service people look at it. I'm thinking it's something simple going on and hopefully a simple fix. I wouldn't rule out the 12v battery needs replacing.

 

[G-Zeus]

Interesting. I have been getting lots of those electrical system drain messages. I’ve been logging them to determine if there is any pattern or connection with charging times or temperature. Not really sure, but I’m going to bring all that into the dealer.

Something is not right, it’s like there is some stuck process that needs to be killed - which you are probably doing when you disconnect the battery.

did you ever try to set a departure time? I tried that and my heated steering wheel stopped working. After doing some FDRS updates, and many hard reboots of the car where the power shuts down hard before it grinds through an update, the steering wheel heat worked again. I tried to check if the departure time but had been fixed, and nope, no more heat on the steering wheel and it doesn’t work after removing the departure time.

I’m wondering if there is a way to use Forscan to reset modules, one at a time, to figure out if any of them are causing it. But I don’t want to mess up anything either! So I’m first going to try the battery disconnect to see if that does anything.

so annoying with some of these issues! I have to reset my sync system on just about every drive when the GPS goes all inaccurate and my car starts drifting all over the map - which not only messes up my home charger location and settings… but also screws with my cruise control when it thinks I’ve hit a 10 mph zone while I’m on the highway, and hits the brakes!

 

[Maquis]

When applying updates with FDRS, it’s mandatory to put a charger on the 12V battery. Every update instruction from Ford has this as step 1.

 

[G-Zeus]

I’m wondering if there is a way to use Forscan to reset modules, one at a time, to figure out if any of them are causing it. But I don’t want to mess up anything either! So I’m first going to try the battery disconnect to see if that does anything.

Answer = YES

I was programming the adaptive head lighting mode, and during this procedure my heated steering wheel started working again. So I went into the SCCM module and this is where you can enable/disable the heated steering wheel AND also set the temperature for it! I like a hot wheel, so I maxed it out at 39 degrees C. And if it ever stops working, I can just go in and do a reset on the SCCM and it should work again.

 

[G-Zeus]

When applying updates with FDRS, it’s mandatory to put a charger on the 12V battery. Every update instruction from Ford has this as step 1.

Indeed. Some of those updates sound like they put quote the load stress on the vehicle! When I did the very first update and the truck power blinked out, and then whatever noise it started making while it was doing the update -- I thought I broke my truck! Then it came back and all was good... nobody warned me about that crazy noise! lol

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