Disconnecting the 12V Battery to "fix" a problem - BMS Learned Values Reset

[carys98]

Thanks. BMS module PN ends in BA, so looks like it's already been revised.

Does the fact that I don't get the three flashes from red battery icon indicate that BMS reset is Not happening? I did hear a split second random sound/noise about 45 seconds after I pressed the brake pedal 3 times, but that was it. Also noticed that the button located on the frunk now does not open or close it but the button to the left of the steering wheel works. Will check again after driving.

If it didn’t flash I don’t think it worked. You have to be in accessory mode so don’t push the brake when you push the start button. You said you have an OBD dongle and app so you should check the 12V SOC before and after the reset. It should change. That can also allow you to see any codes that may have been set that might help isolate the problems you’re having .

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[rogerfranzis]

OK, figured out why BMS wasn't resetting. You have to perform the procedure within 10 seconds of power on. Once BMS reset, active Voltage changed from ~13.2 to ~14.2 so that's a good sign. Will drive again and continue monitoring.

P.S. Do you have to do anything extra to enable lights on running boards? Pro's don't come with side steps but there are pigtail adapters with dummy plugs that can be removed to connect lights. I plugged them in but no LED's came on.

 

[bmwhitetx]

Sounds like you may need Tow Tech. Couple of posts where it was plug and play except for Pros without TowTech.

https://www.f150lightningforum.com/forum/threads/oem-running-boards-for-pro.11033/post-302661

https://www.f150lightningforum.com/forum/threads/f150-lightning-forscan-thread.11406/post-370461

Also I always remind folks to check the ICE forum for a possible solution.

 

[ExCivilian]

Are we supposed to charge the battery to 100% and then do the BMS reset or perform the BMS reset before charging the battery to 100%?

 

[El Duderino]

Are we supposed to charge the battery to 100% and then do the BMS reset or perform the BMS reset before charging the battery to 100%?

Always after

 

[ExCivilian]

hahaha, I'm sorry I'm still having trouble understanding but what always after what?

does that mean the BMS reset is always after the charge or the charge is always after the reset?

 

[RLXXI]

hahaha, I'm sorry I'm still having trouble understanding but what always after what?

does that mean the BMS reset is always after the charge or the charge is always after the reset?

Charge it then reset the BMS.

 

[Mike G]

hahaha, I'm sorry I'm still having trouble understanding but what always after what?

does that mean the BMS reset is always after the charge or the charge is always after the reset?

Charge it then reset the BMS.

Or reset the BMS and go for a nice long drive.

 

[bmwhitetx]

Are we supposed to charge the battery to 100% and then do the BMS reset or perform the BMS reset before charging the battery to 100%?

Honestly, I don't think it matters. Dealers, Auto Zone etc, slap in a new battery and you're on your way without charging the battery first. Dealers might do a BMS reset but they ain't charging it first.

The BMS will calibrate itself eventually. The Workshop Manual states for battery replacement to install battery and reset BMS, nothing about charging it.

It'll be fine.

 

[RLXXI]

Or reset the BMS and go for a nice long drive.

Or just park it and leave it alone for 8 hours after the battery charging or replacement. Or use FDRS or Forcan and reset the BMS.

 

[Mike G]

Or just park it and leave it alone for 8 hours after the battery charging or replacement. Or use FDRS or Forcan and reset the BMS.

Laptop not required to do this.

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