Mike G
Well-Known Member
- First Name
- Mike
- Joined
- Mar 27, 2022
- Threads
- 25
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- 6,458
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- 5,298
- Location
- N. AL, USA
- Vehicles
- '23(J1) Mach-E GT-PE, '22 F-150 Lightning, '24 Bronco HLE 2Dr
Just like your cell phone manages and monitors battery charge and performance over it's lifetime, there is a battery monitor that provides info on the state of charge and life expectancy of the 12V battery in your vehicle to the PCM and BCM. When the battery is first installed a 'baseline' needs to be established. So the tech runs the routine to reset the battery monitoring system's learned values to do that. That battery monitor attached to the negative post on your 12V battery isn't supposed to be removed over the course of it's lifetime. And when programming takes place or for some reason it's necessary to provide a boost to the 12V battery the negative terminal of the charger should always be attached to a vehicle ground point, and not the negative terminal of the battery itself, or the charge learned values will be thrown off and an artificial threshold will be established that could lead to the battery monitoring system continually under-charging the 12V battery and reducing the life expectancy.Thanks, Mike. Will try the “Battery Learned Values” override/reset sequence.
From context, I guess it can — for reasons I cannot imagine — somehow deliberately prevent the 12v battery from being charged beyond the 80% required threshold for receiving OTA software updates!?
Can you (or someone) explain the “Battery Learned Values” concept/purpose and rationale? ??
There are posts on this forum and on the F-150 forum(s) that talk about solutions to getting OTAs recently that instead of pulling and reinstalling fuses (like for the TCU), that instead it's 'easier' to just disconnect the battery and let it sit for a few minutes, to hopefully clear whatever issue was at hand. Well this disconnecting and reconnecting of the 12V battery terminals could cause the learned values to be thrown off. So that in turn could throw off the BMS as to what the actual state off charge of the 12V battery is...and if it's not at 80% when the system is set to check for an OTA update then you can see how that might impact whether or not the OTA proceeds.
I have nearly 50 TSBs, SSMs, etc. in my documents that I use for reference and in all of them the procedural steps include instructions to the tech during programming that if the FDRS reports that the battery is below 80% and it isn't recovering with the charger attached (or even if it is) to first reset the BMS values with the routine in FDRS before proceeding. The process I described before with flashing the high beams and pressing the brake pedal is the way you do it without using FDRS.
To see what I mean, read step one under the "Module Software Updating Procedure" of the attached TSB 23-2122.
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