Electrical system drain and repair ordeal

[Kkbrit]

I wanted to share my experience when I got the “electrical system drain” message. I’m not technical so I’ll do my best.
I took it to my dealer and they said the battery management sensor was bad and ordered a new one. While waiting the week for it to come in I had a slight burning smell in the cabin but thought it was from another car.
The part came in and the sensor was replaced. There was a continued battery draw at the 12 volt system. Testing showed the DC/DC converter was not shutting down and was overheating causing the battery drain. New converter ordered and 3 days to get it shipped. Dealer was able to provide a loaner.
DC/DC converter was replaced and battery draw was still happening. Further testing showed the 200 amp fuse was open and a new one ordered, 2 days to ship.
200 amp fuse replaced and no battery drain noted. Now the 12 volt battery was losing CCA due to drain and showing erratic voltage readings so a new one was installed. Battery SOC 83%.
Total of 8 days in the dealer and I did open a case with the BEV team to report it. The scariest thing was realizing I must have been smelling the DC converter overheating while I was driving. The dealer did a great job of taking care of it all.

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[Mach-Lee]

The battery was probably just bad and all that other stuff was unnecessary because they couldn't diagnose it right the first time. You maybe had a shorted cell. I think it's possible they blew the 200A fuse while replacing the DC/DC if they forgot to disconnect the battery first.

DC/DC converter is under the hood, I don't think you'd smell that (it's liquid cooled). If your 12V battery was failing you might have possibly detected a sulfur rotten egg like smell.

 

[bshaw]

I think it's possible they blew the 200A fuse while replacing the DC/DC if they forgot to disconnect the battery first.

This is scary, if true. I thought step #1 in the EV tech manual was "Disconnect the HVB before doing anything else". Someone could get really hurt by coming into contact with a live HVB.

 

[DMO]

This is scary, if true. I thought step #1 in the EV tech manual was "Disconnect the HVB before doing anything else". Someone could get really hurt by coming into contact with a live HVB.

I am getting the 12V Battery drain message, does anyone know how to solve this issue. The dealer is telling me over 600 to diagnose the issue.

 

[bshaw]

I am getting the 12V Battery drain message, does anyone know how to solve this issue. The dealer is telling me over 600 to diagnose the issue.

Do you have anything connected in the car, or did you grant any apps or chargers access to your FordPass username/password?

If yes to above, disconnect all of those first.

 

[DMO]

Nothing at all......Does this make sense? " While diagnosing your vehicle the tech found codes in the system relating to the ignition status and the headlamp switch module which would cause the electrical system drainage. There is a SSM (special service message) related to the code about the headlamp module advising us that the headlamps can turn on by themselves when vehicle is off. The tech is looking further into it just to make sure the special service message would fix the headlamp code. We are also looking into the ignition code, the only thing is to look deeper into that code we would have to remove the center console. To remove the center console and perform further testing would be an additional 2 hours and would come up to $619.65. The $619.95 is only for diagnosing the electrical system drainage you are experiencing and properly correct the issue."

 

[bshaw]

Nothing at all......Does this make sense? " While diagnosing your vehicle the tech found codes in the system relating to the ignition status and the headlamp switch module which would cause the electrical system drainage. There is a SSM (special service message) related to the code about the headlamp module advising us that the headlamps can turn on by themselves when vehicle is off. The tech is looking further into it just to make sure the special service message would fix the headlamp code. We are also looking into the ignition code, the only thing is to look deeper into that code we would have to remove the center console. To remove the center console and perform further testing would be an additional 2 hours and would come up to $619.65. The $619.95 is only for diagnosing the electrical system drainage you are experiencing and properly correct the issue."

There was a strange bug in the headlamp switch that would cause the headlights to flip from Auto to ON. I believe the only fix was to replace the switch itself.
Did you ever find the headlights were on after parking the car?

I don't know anything about the ignition status code. Maybe others on here could chime in if they know about that one.

 

[DMO]

There was a strange bug in the headlamp switch that would cause the headlights to flip from Auto to ON. I believe the only fix was to replace the switch itself.
Did you ever find the headlights were on after parking the car?

I don't know anything about the ignition status code. Maybe others on here could chime in if they know about that one.

When I first got the car the headlights stayed on, I had to walk back to the car and turn them off and then back to auto. I have not noticed that recently. I guess I will shut the auto lights off for a while and see if the message comes back. Stinks to have a 65K car with manual headlights, but I don't really trust the dealer to find a solution by taking my car apart.

 

[bshaw]

You could also try just replacing the 12V battery, which you'll have to eventually do anyways, and its a lot cheaper than $619.95 for "diagnosis".

 

[DMO]

You could also try just replacing the 12V battery, which you'll have to eventually do anyways, and its a lot cheaper than $619.95 for "diagnosis".

I might give that a try, do these batteries have a history of early demise? I have had the vehicle since September of 2021, would have expected at least 5 years.

 

[bshaw]

I might give that a try, do these batteries have a history of early demise? I have had the vehicle since September of 2021, would have expected at least 5 years.

It definitely should be lasting more than 2.5yrs. A couple people have reported replacing their 12V within 3-yrs, but I don't recall seeing very many of those posts.

Mine is just about exactly 3-yrs this month, and haven't noticed any issues. I do have less than 1/2 your mileage though.
Based on ICE cars I've driven, between 3 and 5 yrs seems to be when a 12V stops holding a charge very well.

 

[DMO]

Can you test the 12V battery capacity in place, or do you need to remove. It looks like a 300$ part, hate to replace it if it is still good.

 

[bshaw]

I would think you could test it in place, but you need a specialized device to do it. Would have to take off those frunk panels to get in there too.

I just looked on Autozone, and they don't seem to have aftermarket options for a Mach-E 12V replacement. Strange.

 

[Msnwcpa]

The battery was probably just bad and all that other stuff was unnecessary because they couldn't diagnose it right the first time. You maybe had a shorted cell. I think it's possible they blew the 200A fuse while replacing the DC/DC if they forgot to disconnect the battery first.

DC/DC converter is under the hood, I don't think you'd smell that (it's liquid cooled). If your 12V battery was failing you might have possibly detected a sulfur rotten egg like smell.

I just got the “Electrical system drain” message with my 2023.5 Mach E this afternoon. It’s a nice day in Southeastern PA. I plugged the car in and called the dealer, they seem to be clueless, they said they do not see any errors. I have errors showing up in my FordPass App.

 

[Machroots]

I just got the “Electrical system drain” message with my 2023.5 Mach E this afternoon. It’s a nice day in Southeastern PA. I plugged the car in and called the dealer, they seem to be clueless, they said they do not see any errors. I have errors showing up in my FordPass App.

Funny I just got this same message last Wednesday on my 2023 GT(7400miles). My dealer said they saw something on one of the battery modules that they want to look into but they can’t get to the car until possibly this Wednesday. I also just got this message again while my car was parked in my garage.

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