Official Instructions to Replace the 12V Battery (LVB)

breeves002

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I had come across some threads today about LVB issues. Having owned a Focus Electric in the past I know how bad 12v batteries can be in EVs. Hoping the Mach-E doesn't have issues.

I decided to do some research and found information Ford recommends for replacing the 12v battery - and I must say it is way too complicated. I have no idea what they were thinking or why it is this complicated of a process.

Disclaimer: Do not take my word for any of this. I am the messenger and fixing cars with HV systems can be dangerous if you don't know what you're doing or have the proper tools.

To replace 12v Battery

Remove all of the trim pieces under the hood and the luggage tub completely. I don't know if this is truly necessary, you may be able to wiggle it out but it does look like it is partially underneath it.
Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 0

Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 0.01

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Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 0.04

Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 0.05

Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 0.06

Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 0.07


Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 0.09

Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 0.10

Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 0.11


Next step is to de-energize the HV system.
Note: I have no idea why ford wants you to do this but its in there. They have a procedure to do this including using FDRS to confirm the HVB is de-energized or a "manual" way to do it with a ton of warnings. Manual way is also done with FDRS...just no FDRS confirmation it is at 0 voltage.

It appears there is a "lock out tag out" type device under the hood they call the CPA or Connector Position Assurance. Procedure is simple. Push the tab and pull the connector out, then put something in the hole to keep it from clipping back down. Now in theory the system is de-energized.
Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 10

Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 11

Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 12


Once the HV is de-energized they call for removing the negative battery cable from the chassis and taping it. After doing that you are supposed to remove the negative from the battery (remove current sense connector) and then positive from the battery. You also have to remove the strut tower brace to get the LVB out...though without the luggage tub you could probably slide it out.

Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 0.1

Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 0.2

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Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 1

Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 2

Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) 3


This seems extreme. Are dealers going to actually do this whole procedure? Is it too dangerous to replace your own LVB? AutoZone certainly will not do it for you... I also really hope luggage compartment removal isn't necessary as it seems like a massive pain.

Last note - I feel like the HV system de-energization is more of an extra safety thing although it shouldn't actually be needed. DO NOT take my word for that though because you can kill yourself or damage your car if you don't do things the way Ford has said to do it!
 

Garbone

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I could see this being replaced with a marine box and deep cycle golf cart battery in the frunk if I had to replace it outside of warranty. Seems a bit absurd as far as the plastic clips and widgets go.
 

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Wow - this is a lot of surgery to replace the battery that is visible when the three panels are removed. Pretty much requires Ford dealership to do this
 
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breeves002

breeves002

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That wins my vote for dumbest design ever - by a wide margin.
Dubmest ever? Not sure about that, but it is up there in the dumb design category.

Also dumb design...not including an owners manual. It nice and on the touchscreen, but what about those times the touchscreen doesn't work. C'mon Ford.
 


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Last note - I feel like the HV system de-energization is more of an extra safety thing although it shouldn't actually be needed. DO NOT take my word for that though because you can kill yourself or damage your car if you don't do things the way Ford has said to do it!
They do that because the car wakes up periodically to charge the 12-volt. The idea is that battery replacement "should" be relatively rare as it's an AGM battery and the HVB should be maintaining the LVB.

The recent posts about the LVB dying is because the system is not working as designed. Time will tell if the design proves itself.
 
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breeves002

breeves002

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louibluey

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No, I don't have a link these are screenshots I took out of a database that requires a login.
I kinda figured that from one your later posts. Thank you for posting the instructions!
 

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No, I don't have a link these are screenshots I took out of a database that requires a login.
I'm curious as to how you would discharge the battery? I don't think rolling the lift-cart into a pond would work...?
 

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Dubmest ever? Not sure about that, but it is up there in the dumb design category.

Also dumb design...not including an owners manual. It nice and on the touchscreen, but what about those times the touchscreen doesn't work. C'mon Ford.
I'm all about not sending a paper manual never used it and I'm on a paper they're saving. Sorry but in today's era there's not a time when you don't have your phone on you so you can go in the Ford pass and look up the manual and or literally just Google search it like I always do for anything if I got to check fuses.

This is up there in poor design. If they could of pushed it back maybe so just the top section of trim would have to be removed that'd be a huge advantage over the current design.
 

louibluey

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I changed out my 12V LVB today. The removed LVB is fine, I am studying learning about AGM batteries and curious about measurement of LVB aging.

I think that I understand some of weirdness of the LVB replacement procedure.

Possibly the reason that they want to remove the chassis side of the negative battery cable is related to the battery side. On the battery side if you loosen the 10mm nut and pull directly up, all is okay, many of us use that procedure to cold boot the MME. The problem is that the way they laid out the relatively heavy #2 cable is that if you let go of it, it falls back down making contact with the battery negative terminal. I either use a leather work glove or towel, or best tape the removed negative cable with electrical tape to the strut tower brace above when working 12V power off.

Also, for some as of yet unknown reason, they want you to change out the sensor and cable when you change the LVB. So, I guess that way (removing the ground cable on the chassis side) you take out both at the same time. My sensor and cable are new and shiny, I'm reusing them until there is a good reason to change them out.

So, by removing the other side, the 13mm nut like ground post (the ground jump post) and taping that one, you solve the resting on the terminal problem. But, that washer for the ground terminal has a long locating metal tab that goes down through a chassis opening. So, you have to angle it to get it out. Well, to angle it you either bend the ground cable or remove the strut tower brace!

I also agree that that (at your own risk disclaimer) opening that little plastic HV off switch is nutty at best. Once you remove the 12V LVB, HV is not coming on. So, having had the frunk tub out and apart 10+ times for various reasons, I never opened that stupid little switch until today. Then, of course I forgot and buttoned everything up and had to pull panels again to reset it.

It is not only possible to slide the battery out without removing the strut tower brace, there is gobs of room, not even close. There may be some industrial safety issue where it is "safer" to lift a heavy battery straight up. Otherwise, no issue, leave the strut tower brace alone (at your own risk of course).

It helps to have a long extension tool shaft for the 8mm rear two bolts of the metal flange bracket that holds the battery in the tray.

The whole process not including distractions, is about an hour or less.
Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) Unknown
 
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My dealer is telling me that my LBV in my 2002 GT is weak and needs to be replaced. I only have 3,500 miles on the car, and I have never had a 12V battery on any ICE go out in less than 2 years, it is usually 5+ years and lots of miles. The topper is they claim there is a national shortage of batteries, and it is on backorder. Of course, I had the HVBJB Replacement that took almost 2 months (got it back right before New Years) so really, I only have 18 months on the battery.
 

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I changed out my 12V LVB today. The removed LVB is fine, I am studying learning about AGM batteries and curious about measurement of LVB aging.

I think that I understand some of weirdness of the LVB replacement procedure.

Possibly the reason that they want to remove the chassis side of the negative battery cable is related to the battery side. On the battery side if you loosen the 10mm nut and pull directly up, all is okay, many of us use that procedure to cold boot the MME. The problem is that the way they laid out the relatively heavy #2 cable is that if you let go of it, it falls back down making contact with the battery negative terminal. I either use a leather work glove or towel, or best tape the removed negative cable with electrical tape to the strut tower brace above when working 12V power off.

Also, for some as of yet unknown reason, they want you to change out the sensor and cable when you change the LVB. So, I guess that way (removing the ground cable on the chassis side) you take out both at the same time. My sensor and cable are new and shiny, I'm reusing them until there is a good reason to change them out.

So, by removing the other side, the 13mm nut like ground post (the ground jump post) and taping that one, you solve the resting on the terminal problem. But, that washer for the ground terminal has a long locating metal tab that goes down through a chassis opening. So, you have to angle it to get it out. Well, to angle it you either bend the ground cable or remove the strut tower brace!

I also agree that that (at your own risk disclaimer) opening that little plastic HV off switch is nutty at best. Once you remove the 12V LVB, HV is not coming on. So, having had the frunk tub out and apart 10+ times for various reasons, I never opened that stupid little switch until today. Then, of course I forgot and buttoned everything up and had to pull panels again to reset it.

It is not only possible to slide the battery out without removing the strut tower brace, there is gobs of room, not even close. There may be some industrial safety issue where it is "safer" to lift a heavy battery straight up. Otherwise, no issue, leave the strut tower brace alone (at your own risk of course).

It helps to have a long extension tool shaft for the 8mm rear two bolts of the metal flange bracket that holds the battery in the tray.

The whole process not including distractions, is about an hour or less.
Ford Mustang Mach-E Official Instructions to Replace the 12V Battery (LVB) Unknown
Why did you replace the battery?
 
 




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