Weird Charging Issue -- Possibly after module replacement: Fix post #72

[AntJohn73]

I am figuring that this is exactly what my truck needs.

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[Mpi]

My dealer has confirmed a full balancing is needed. The service rep told me the original instructions from Ford were to balance the new module to match the battery. Now Ford tells them a more involved balancing is needed where each module, new and old, will be balanced and the voltage set to some common level before reinstallation. I'm not sure how accurate all that is, but it's what I'm told.

So such a condition as we've been discussing does exist, and it won't necessarily throw a wrench light or brick the truck. If you are aware enough of your vehicle this should be a good thing.

Another update: in the process of balancing they found that one of the replacement modules was bad.

So it seems that in fact even a bad module might not throw a yellow wrench! It still seems like a good thing that the truck remains driveable, but you'd think there should at least be an indicator light for a bad module.

 

[GoodSam]

in the process of balancing they found that one of the replacement modules was bad.

How many replacement modules did you have done for the Safety Recall 25S18 back in October, 2025? And, just to confirm, one of those new modules put in went bad? Yipes!

 

[Mpi]

How many replacement modules did you have done for the Safety Recall 25S18 back in October, 2025? And, just to confirm, one of those new modules put in went bad? Yipes!

I need to clarify with the dealer whether the bad module is the new one. Looking at my charge history, I suspected is was bad out of the box because it 'falsely' charged to 100% the first time the dealer charged it.

 

[Mpi]

I'm not sure how @AntJohn73 has fared, but for me the saga continues.

I got a call end of day yesterday that my truck was ready. A battery module was replaced, the BECM module was replaced, and the truck successfully charged to 100%. Great! (@GoodSam I clarified the replaced module was not in fact the one that went in under recall 25S18).

As I left this morning to pick it up I remotely started the climate, observing 100% SOC indeed. I arrived 15 minutes later to find it at 69% SOC. I told the rep it was weird and familiar behavior. The service manager came out to talk to me, and we agreed to plug it in to charge for half an hour while I dropped off my daughter. Of course, when I got back it was fully charged to 100%.

Replacing the BECM was due the Ford engineering's theory that it had caused the module failure. Back to the Ford engineers now to figure this out. The good thing is that the dealer is very supportive and has me in a nice loaner, albeit an ICE truck.

 

[LiteNing]

I might as well post my update too:

Dropped off the truck last week Thursday. I wrote down my symptoms in the reservation (basically same as Mpi and AntJohn73) and also explained the same verbally to the service writer.

To help them diagnose the issue as the HV battery, I also mentioned that supercharging slows down at 72% instead of the expected 80% (8% early)... just like the top 8% of the battery is unusable. That may have been a mistake.

Friday the diagnosis came back that I needed a new charge port. Sensor is reading 400F. I asked if they ran any HVB diagnostics... nope. They claim the workshop manual says they need to do the charge port first.

So for anyone in the future with this problem: Maybe don't mention the supercharging symptom if you have it.

The charge port is covered under the 100k/8yr warranty, but the service writer said it's hard to replace without damaging another part that isn't covered. Good thing I got an extended warranty...

They're supposed to have the charge port done today. I'm cautiously optimistic that today they will actually start the HVB diagnostic.

 

[GoodSam]

Back to the Ford engineers now to figure this out.

What is the build date, & miles at problem, showing on your trucks (driver's door sticker)? @LiteNing @Mpi

 

[Mpi]

What is the build date, & miles at problem, showing on your trucks (driver's door sticker)? @LiteNing @Mpi

About 22,300 miles. I will check the build date when I have it back.

 

[AntJohn73]

@Mpi This is my update. It turns out that there is a second bad module. The module is on order. They allowed me to take possession of the truck until the module arrives. That turns out to be a good thing because we are expecting a decent amount of snow this weekend. I has a Ford Edge as a loaner (yuck). I will be bringing it back in February. Hopefully everything will be resolved. One thing I will say is the dealership has been very respectful and nice to me. I just hope this is the last part of the saga. It sucks because the truck is excellent and has such a smooth ride.

 

[LiteNing]

What is the build date, & miles at problem, showing on your trucks (driver's door sticker)?

Door sticker says date is 12/22 (had to find a picture from a few months ago). Current milage is ~47500, but I would estimate I saw the first symptoms around 46k, maybe as early as 45k.

The previous module replacement was at 40k miles.

 

[LiteNing]

I might as well post my update too:

Another week another update. They finished the charge port! Service writer called me on Friday with the happy news! Did they diagnose the HV battery, like I asked last time we spoke on the phone? Uh, no, but the charge port is fixed! Did they at least test the very specific symptoms that I wrote down when making the service appointment and then reiterated verbally to the service writer on the phone? Well no, but the charge port is fixed!

Sigh...

So I explained the problem again.

I can see in FordPass that they charged it to 100%. Hopefully 3rd time's a charm. At least the ownership experience isn't boring!

 

[AntJohn73]

I wanted to post what I am hoping is my final update. The dealership replaced module #2 and I have taken possession of the truck. It successfully charged to 100% and the charge curve appears to be normal. On a level 2 charger, the charge current does not start to ramp down until it is over 90%. My variance between modules is now at 2% as opposed to over 20% when the issue was occurring. My scan tool indicates that the battery is in a state of re-balancing which I think is normal after this type of work? Any tips on how to achieve a balance sooner?

 

[chriserx]

I wanted to post what I am hoping is my final update. The dealership replaced module #2 and I have taken possession of the truck. It successfully charged to 100% and the charge curve appears to be normal. On a level 2 charger, the charge current does not start to ramp down until it is over 90%. My variance between modules is now at 2% as opposed to over 20% when the issue was occurring. My scan tool indicates that the battery is in a state of re-balancing which I think is normal after this type of work? Any tips on how to achieve a balance sooner?

Drive and charge, typically what's meant by time.

 

[Mpi]

I wanted to post what I am hoping is my final update. The dealership replaced module #2 and I have taken possession of the truck. It successfully charged to 100% and the charge curve appears to be normal. On a level 2 charger, the charge current does not start to ramp down until it is over 90%. My variance between modules is now at 2% as opposed to over 20% when the issue was occurring. My scan tool indicates that the battery is in a state of re-balancing which I think is normal after this type of work? Any tips on how to achieve a balance sooner?

Great to hear. L2 charge to 100% and let it sit overnight, should go a long way towards balancing out the remaining 2%

 

[AntJohn73]

Thanks. I will keep an eye on it.

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