BMS bad?

[crregan83]

For the second time in a week my 2019 Expedition Max would not start. Seemed to have full power but not enough to start. Voltage was around 11.4. The issue is that the Battery Monitoring System BMS is seemingly not functioning. My understanding is that the BMS will go into battery saver mode before it drops below 12V. I used FORScan Lite to try and reset the module but I get the following errors. I also tried the reset using the high beams and brakes and that seemed to work (battery light flashed 3-4 times then went off).

I successfully jumped the car both times and it started right up. The first time was last week and the temps were around 10-15 degrees F and the vehicle had been driven less then 12 hours prior. I drove it to work and got the battery tested (analog) on the way at NAPA thinking it maybe was bad. I bought the vehicle used in January 2023 but not sure if the dealer replaced the battery or it ifs older then 2 years. NAPA said the battery was in good shape so I figure it was just the cold.

The second time was this morning and it was around 35-40 degrees but the vehicle had not been driven in about 36 hours. I drove it to work (30 min trip) and then after it sat for a bit I checked the voltage again and it was up to 11.8V and started just fine.

Does the BMS not operate if the voltage is already below 12v?

Do I need to have the battery with a digital tester like AutoZone?

Is there a way to test the BMS with a multimeter? Should I just replace it?

Any thoughts would be appreciated.

 

[Fizzy]

All this messing around, and it's just because your battery is toast. Resting 11.4v is a dead battery. It's very likely the original factory battery from 2019. NAPA might say it's fine, and in an older predominately analog vehicle, that may be the case. But these trucks are laptops on wheels.

There's nothing wrong with your BMS.

 

[crregan83]

All this messing around, and it's just because your battery is toast. 11.4v is a dead battery. It's very likely the original factory battery from 2019. NAPA might say it's fine, and in an older predominately analogue vehicle, that may be the case. But these trucks are laptops on wheels.

There's nothing wrong with your BMS.

View attachment 83522

That’s what I originally thought the first time but the test came out fine.

On the BMS errors in the scanner, would the low voltage possibly cause it to malfunction?

 

[Fizzy]

That’s what I originally thought the first time but the test came out fine.

On the BMS errors in the scanner, would the low voltage possibly cause it to malfunction?

Very likely. When you take your old battery out, you'll see a Date Mfg sticker on the side. I'll bet yours says 2018 or 2019. 6+ years is far longer than batteries last in these trucks.

Get a new H7 AGM. Make sure it's AGM, and not a FLA (flooded lead acid). There was a long discussion thread recently on replacement battery brands and warranties. It's here.

Also, the BMS reset procedure (high beams etc) is for when you replace the battery. Make sure you do it when you put your new battery in to tell the truck it has a new battery and so it doesn't treat the new battery like the old one.

 

[LokiWolf]

Fizzy nailed it. You need a new battery. You need to isolate the battery to test it fully and most shops don't do that. Even then, load is what matters, and they typically don't have load testers or use them properly.

Only thing I would add, is the BMS reset is only for if you replaced it and want to have the BCM immediately reset and start learning again. You really don't need to do it, if the vehicle is going to sit a few hours after replacement, because it resets anyway. Honestly I have never done the reset procedure when replacing any of my batteries. Only done it as part of module updates, because it was part of the procedure.

 

[DieselMonk]

Not sure why that is with the battery drain, but it seems the 2018, 2019 and the 2020 ford full size trucks and SUVs have that problem. For example folks camping opening and closing the door, or working out of a truck, or lots of short trips will kill the battery.
First you notice the start stop won’t work, then all of the sudden your fuel mileage goes to hell, then weird shit is happening, etc… has to do with a bad battery.
I went from a 2018 F150 to a 2024 Expedition. The original batteries were a size H8 in the F150 down to size H6 in the Expedition. The new Expedition doesn’t kill my battery as fast than the old F150 did.
If you do change the battery size you need either the dealer or Forscan to program the BMS.
The reset procedure does not code the battery size.
Also buy a quality AGM battery and do not replace with a flooded regular battery.

 

[LokiWolf]

Not sure why that is with the battery drain, but it seems the 2018, 2019 and the 2020 ford full size trucks and SUVs have that problem. For example folks camping opening and closing the door, or working out of a truck, or lots of short trips will kill the battery.
First you notice the start stop won’t work, then all of the sudden your fuel mileage goes to hell, then weird shit is happening, etc… has to do with a bad battery.
I went from a 2018 F150 to a 2024 Expedition. The original batteries were a size H8 in the F150 down to size H6 in the Expedition. The new Expedition doesn’t kill my battery as fast than the old F150 did.
If you do change the battery size you need either the dealer or Forscan to program the BMS.
The reset procedure does not code the battery size.
Also buy a quality AGM battery and do not replace with a flooded regular battery.

There is ZERO coding in the computer for the size of the battery. Only settings are AGM vs Standard and SOC goal. That is so it knows charge rate, and the minimum SOC to try to maintain.

Throw a bigger battery, but no so big you cannot maintain the insulation wrap around the battery. It is important for temperature isolation.

 

[DieselMonk]

There is ZERO coding in the computer for the size of the battery. Only settings are AGM vs Standard and SOC goal. That is so it knows charge rate, and the minimum SOC to try to maintain.

Throw a bigger battery, but no so big you cannot maintain the insulation wrap around the battery. It is important for temperature isolation.

There was on my 2018 F150 using Forscan. I could code different battery sizes in no problem. I haven’t looked at my Expedition yet, but it should be similar. Maybe once it gets warmer out without freezing my butt off I’ll take a look and see what can be done on my new ride. I had coded quite a few things on my old truck, from downhill assist over to daytime running lights, the double honk when closing the door from outside with the engine running, etc.
Yeah, you can’t fit an H6 battery insulation cover on an H8. The size difference would be to extreme. However, it happens that I have a brand new H8 that would like to be installed! Maybe in the spring…

 

[Calidad]

Umm battery is dead. Even before it gets that low you should see issues. Weird shifting, sun roof won’t open, running boards don’t work etc.

Get a new battery.

 

[LokiWolf]

There was on my 2018 F150 using Forscan. I could code different battery sizes in no problem. I haven’t looked at my Expedition yet, but it should be similar. Maybe once it gets warmer out without freezing my butt off I’ll take a look and see what can be done on my new ride. I had coded quite a few things on my old truck, from downhill assist over to daytime running lights, the double honk when closing the door from outside with the engine running, etc.
Yeah, you can’t fit an H6 battery insulation cover on an H8. The size difference would be to extreme. However, it happens that I have a brand new H8 that would like to be installed! Maybe in the spring…

One more time…nothing you have to research. It doesn’t exist. Ford removed the coding. Never existed on the 4th Gen Expeditions, and does not exist on the 14th Gen F150’s(21+) either. It just isn’t needed and really didn’t do anything functional.

Just swap a new, and larger AGM in and go on down the road. No reason to reset the BMS unless you have issues. The next time it sits during the day or over night it will relearn.

 

[DieselMonk]

One more time…nothing you have to research. It doesn’t exist. Ford removed the coding. Never existed on the 4th Gen Expeditions, and does not exist on the 14th Gen F150’s(21+) either. It just isn’t needed and really didn’t do anything functional.

Just swap a new, and larger AGM in and go on down the road. No reason to reset the BMS unless you have issues. The next time it sits during the day or over night it will relearn.

Aah! Ford changed that with that back in 21… Didn’t know that yet. My old 18 that I sold had it and the 19 have it and now my 24 is the newest and I never looked. My battery went bad after 5 years in the 18 F150 causing all kinds of weird issues. So I replaced it and all the issues went away just like magic.

I still like to know why the latest model years battery size got downsized? Makes no sense a Ranger having an H7 vs the Expedition having an H6? I do know that the battery is now always full on short trips and is able to recoup much faster than my old F150 with a 160A alternator did. Must be a more aggressive charging programming?

 

[LokiWolf]

Aah! Ford changed that with that back in 21… Didn’t know that yet. My old 18 that I sold had it and the 19 have it and now my 24 is the newest and I never looked. My battery went bad after 5 years in the 18 F150 causing all kinds of weird issues. So I replaced it and all the issues went away just like magic.

I still like to know why the latest model years battery size got downsized? Makes no sense a Ranger having an H7 vs the Expedition having an H6? I do know that the battery is now always full on short trips and is able to recoup much faster than my old F150 with a 160A alternator did. Must be a more aggressive charging programming?

Actually, the 4th Gen Expeditions have less modules. More of the coding is in the BCM than the F150. With every new generation of the Expedition it deviates more and more from the 150. People assume that the current Expeditions are like the old ones and basically a 150 with a back. Really not the case any more. The 25's are going to be REALLY different.

Heck Ford did some module and coding changes between the 2019 and 2020 Expeditions, and even more changes between 2021 and 2022.

Our 2020 Limited never had any battery issues, until one cold morning it struggled to start but did. Got replaced that evening with a Diehard Platinum from Advance. No issues again. Did bump up one size then, but not because it was really needed just because the cost differential was negligible.

The Ford OEM batteries over the past 5 years have in my opinion been subpar. The 22+ Expeditions see more battery drain than the 2018-2021 because of the difference in the TCU because of Sync4. It is more active when the vehicle is off like the 21+ 150's.

Personally, at the first sign of issue from any OEM battery I swap it with a quality local aftermarket with a good replacement warranty. Local and good warranty are the important pieces. Could I get better, maybe, but that drive up to the store a few blocks away is very helpful. Swap, hand them the old and drive away.

 

[Fizzy]

@LokiWolf People have had mixed results with the "wait 8 hours and the BMS resets itself" thing. For how simple the reset procedure, and how quick it is to perform (10 seconds), it's probably just better to recommend people do it and actively make sure the BMS has been reset. It's also stated in the owners manual as the procedure to perform when you replace the battery.

 

[crregan83]

Motorcraft from the dealer for $230 for interstate battery from Costco for $180?

 

[LokiWolf]

Motorcraft from the dealer for $230 for interstate battery from Costco for $180?

Motorcraft batteries in my opinion are subpar. I personally also wouldn't buy from Costco. AutoZone, Advance, and buy the AGM Platinum or what ever the top line is called.

 

[LokiWolf]

@LokiWolf People have had mixed results with the "wait 8 hours and the BMS resets itself" thing. For how simple the reset procedure, and how quick it is to perform (10 seconds), it's probably just better to recommend people do it and actively make sure the BMS has been reset. It's also stated in the owners manual as the procedure to perform when you replace the battery.

I get where you are coming from. Never done it like I said unless it was part of another procedure. Swapped the batteries, and moved on. No issues. If you have issues, do it. Otherwise I wouldn't worry about it. That is me.

So many people are doing it as a fix all on the 21+ 150's, and then low and behold a little bit later they have the same problem.

 

[Fizzy]

So many people are doing it as a fix all on the 21+ 150's, and then low and behold a little bit later they have the same problem.

Just like OP - who kept doing it hoping for new results.

Troubleshooting 101. Start at the simplest, most obvious solution, and work down the trouble tree from there.

 

[LokiWolf]

Just like OP - who kept doing it hoping for new results.

Troubleshooting 101. Start at the simplest, most obvious solution, and work down the trouble tree from there.

Yeah, except it will never fix a battery with a resting voltage that low...but yet I am sure somewhere somebody was telling them to do it. Instead of taking all the data in, and telling them to just go get a new battery. Looking in FORSCAN, and all along, the battery was crap. Way more work than was needed.

This problem didn't need FORSCAN, a BMS reset, or anything advanced. Just needed a new battery, cause well it has been crazy cold lately in MD(assuming location is accurate), and the battery is at minimum 2 years old, and most likely the original.

Just random @crregan83 Make sure the BMS plug is plugged in solid too. There have been many that have disconnected it over the years to stop Auto Start/Stop, and that is a terrible idea...but hey, people still do it.

 

[sjwhiteley]

I would just spend the $200 or whatever and get a new battery, and move on with life. I think in almost all modern car forums, when they have had electrical issues on a car a few years old, a battery solves the problem. Treat it as a consumable.

(I've had batteries which test fine, good voltage, good delivery on load, then 24 hours later - unconnected - is almost down to single digit volts).

 

[Ugh_J]

you can’t fit an H6 battery insulation cover on an H8. The size difference would be to extreme. However, it happens that I have a brand new H8 that would like to be installed! Maybe in the spring…

You can get replacement battery insulation blankets that will fit multiple battery sizes. Looking at https://parts.ford.com/shop/en/us/vehicle-battery-80-ah-800-amp-p-bagm94rh7800?pdp=y (the 94R size for my 2020 before the downsize) it looks like the part number for the heat shield is 10a687 and is about $30. That said, I'd probably not use the OEM one and get some of the better stuff online that will fit just about any modern car battery and has the aluminum foil backing.