My dad has a 2015 Mustang GT .
The battery died last year, so we had it replaced, on Mar. 24, 2021.
This weekend, on 4/2/22, she made a clicking noise and the error "Turn Power off to Save Battery" message came on.
The car is dead, no lights or anything and she won't start it at all.

I've seem some forums & YouTube that notes unplugging the Battery Current Sensor or having the battery jumped.
Assuming the battery is fine, again, it's only a year old, what would cause, or fix this?
There is clearly an issue with Ford that these issues arise from most all For models. Bad sensors??

 

There are a few things to keep in mind.
Corrosion takes place without us even knowing it and sometimes can't physically see it.

Anytime we get a situation of no lights, no anything, the first thing to check is the connections at the battery.
Like we always say,,,,,,,,,,,,,looking at them does NOTHING. They can look perfectly good and still be dirty preventing good contact. !
The cable end has to be removed cleaned, and reinstalled.
Dirty or corroded battery cable connections can hamper charging system function. What can appear as a bad battery can be the result of the corrosion preventing the full output of the alternator from reaching the battery. On some vehicles the charging lamp goes out even if the charging rate is less than what the vehicle is using.

 

Thank you for the info!
So, we should clean the cable first and then try it, rather than jumping it?

 

When you jump it, you are by-passing the battery and connections by connecting the jumper clamps to the outside of the cable end.
Good connection guaranteed

The only way to know is to clean the cable connections , then attempt to start it and see what you get.

Don't forget to clean both battery cables.

 

Will do!
Hopefully have some positive follow-up news after this over the weekend. Thank you!

 

The battery was tested by AAA a she was dead in the garage.
The connections were cleaned & was scanned.
It was deemed good, just not fully charged.

I'm taking it into Ford in June as something is clearly wrong.

I've seen that is the BMS isn't reset the battery thinks the old one is in it still.
Does this sound correct or Internet insanity?
If it could be legit, did anyone know the steps to do this? What I found noted to do a bunch of crazy steps, just shy of standing on your head! 🙄


I'm going to get a Battery Tender just in case once this is resolved.
Another question, it was recommended to get the 1.25 amp Tender.
Would it be prudent to get the 3 or 4 amp so it can charge should the need arise to charge it down the road?

 

The 3=4 amp charger would just charge the battery quicker.

 

Thank you on the Battery Tender. Ordered the 4 amp.

Any insight on the BMS reset? Is there a manual reset once a new battery is installed or something Ford/ mechanic needs to do?
Of course Ford is no help at ascertaining information.

 

There could be several reasons for, SOME, Ford dealerships not wanting to be helpful. Maybe some folks drive the personnel up the wall , but cooperation and good will is what helps sell vehicles. The sales dept knows this, but sometimes the service dept comes up a little bit short.

On some newer vehicles, the computer is so smart and yet needs to be told the battery has been replaced. This requires a capable scan tool and the info from the replacement battery.. It does get a little complicated for those of us that don't work with this stuff every day.

A good shop with the equip should be able to assist you if the dealership refuses.

 

Agreed.
What irks me is when you tell them about a reset and they act dumb.

Once the battery gets charged again, I'll try what I find in the manual (attached)

.
Then I'll see what, if anything, Ford finds.