SkierMan

2011 F150. I was messing around last night in the back seat with the key in the ACC position listening to the radio. The radio shut off, I looked at the nav screen and there was a count down progress bar saying to start the truck or it would go into battery save mode. I started the truck and all was well, shut it off, and the radio was not on anymore. Started the truck, no radio. Also, no A/C, no climate seats, no keyless entry, no power running boards. I started pulling fuses in the kick panel and under the hood, all were ok that I checked. I went into the dash display and tried to reset the running boards but it won't reset.

I checked the manual and on page 381 there is a section about battery management system. It says basically, that if the battery reaches a certain state of charge, the BMS will shutoff non essential functions, which are listed as audio, climate control fan, heated and cooled seats, etc. which are my symptoms. I disconnected the negative battery cable for 30 mins, reconnected, no luck.

I connected my ctek charger and let it charge overnight with the cables plugged in.

This morning, the CTEK said fully charged, started the truck, still no AC or Radio. I continued reading and it says after battery replacement, or sometimes after external charging, the battery requires 8 hours of sleep (key off and doors closed) to relearn the state of charge of the battery and prior to the 8 hours, the BMS may disable eletrical features to protect the battery earlier than normal.

I went to a dealer, they never heard of such a thing. Showed them in the manual and they still had no clue what I was talking about. Called another dealer, and they weren't helpful. I read on another forum that the dealer has the ability to reset the BSM to a different state of charge before it cuts off the accessories.

It's 100 plus outside, no AC sucks. I drive about 30 miles home in stop and go traffic. Is there a easy way to reset the BMS?

stormsearch

You are on the right track. As you can see, this is a new function and not many people are aware of the battery management system. I just reviewed the workshop manaul and there is no procedure listed for the BMS reset using the scan tool. However, in our testing we perform the following:

Perfroming a BMS reset will reset the battery SOC to a default of 85%- regardless of its true state of charge and reset the SOC drain timers. This should get you out of load shed. The following is the procedure using the Diagnostic Engineering tool.

BMS reset procedure with Ford "Diagnostic Engineering Tool":
Go to Gen Diagnostics and select Module ID to 726 (BCM)
Select Service 0X10 and extendedDiagnosticSession, and press "Send Message" button
Select Service 0X31
Check "User Defined" box, and type in "201A"
Press "Send Message" button

For all future reference, do not connect the negative charge lead to the negative battery post. Connect it to another ground attachment point on the truck. That way, the re-charge will be measured by the BMS hall sensor (very near the negative battery post) and will correctly re-adjust the battery SOC.

If the dealer plays dumb, here is the section in the workshop manual:

When charging the vehicle battery by connecting the charger to the negative battery terminal is necessary, such as when using a combination battery charger and battery tester/analyzer, like the GR 1 190 V3.0 Intelligent Diagnostic Charger, the BCM will not immediately update the battery state of charge. In this instance, after charging, you must carry out the Battery Monitoring System (BMS) Reset using the scan tool. This reset is needed for proper engine off load shedding and to prevent invoking of engine off load shedding earlier than normal.
NOTE: If the reset is not carried out, when the battery is charged by connecting the charger to the negative battery terminal, it takes approximately 8 hours for the BCM to learn the new battery state of charge. During this 8 hour period, the vehicle must be undisturbed, with no doors opened or keyless entry button presses. If the vehicle is used before the BCM is allowed to learn the new battery state of charge, engine off load shedding can still occur and a message may be displayed.
When charging the vehicle battery by connecting the charger to engine or chassis ground, the negative charger clamp must be connected to an unpainted chassis surface or a solid engine component such as a generator mount or engine lifting eye. In this instance, after charging, the BMS Reset is not required. Through this method of charging the BCM will update the battery state of charge during the charging process.

2000xl_toronto

nice answer stormsearch!

Mine has turned my radio off so far but I haven't seen the countdown timer or anything that hardcore yet

Ford850

If this happens and you start the truck but LEAVE IT RUNNING to recharge the battery, then it won't get locked up? I'm guessing by starting it and immediately shutting it off, you only further drained the battery. What if you replicate the drain cycle by partially draining the battery somehow, and then recharge it by running the truck or with a charger connected to the frame as suggested above? I wonder if that would allow the sensors to recycle and pick up the full charging state and unlock the BMS.

doug77house

Wow. I never heard of such a thing. Maybe these things are getting too smart. Sounds like a pain in the *****, if this just comes from having the radio on.

jlc41

Holy mackrel batman, WTH are we getting into. Everybody better read and reread their manuals. LOL

Car_Expert_2020

Hello,

Seems like Load Shed is getting you there. I will advise that you don't leave anything pluged to the powerpoint if you not running the vehicle. Don't try to reset the BMS. this will not help you long run. but the best way is to start your car and the battery will be charged.

You should have full functionality if the car is running.

alexi

Hello All

I am aware that this topic is over 3 years old. But I've got a general question regarding the quote below:

I've got a CTEK charger and while chraging process is it connected directly to the battery over eyelet connector. Will the BMS recognize the charging process when charger (plus and minus clamps) is connected directly to the battery? Or does the minus connection must be connected to the unpainted chasis surface (or similar)?

Thanks in advance for your reply.
Regards
Alex

Feathermerchant

Like it says, when charging you must connect the minus to an unpainted surface. Y?ou can simulate this if you can run the negative charge wire through the loop that is around the negative battery cable.
As far as resetting, I think if you charge the battery and let the truck sit at least 8 hours for it to learn the battery state of charge:

NOTE: If the reset is not carried out, when the battery is charged by connecting the charger to the negative battery terminal, it takes approximately 8 hours for the BCM to learn the new battery state of charge. During this 8 hour period, the vehicle must be undisturbed, with no doors opened or keyless entry button presses. If the vehicle is used before the BCM is allowed to learn the new battery state of charge, engine off load shedding can still occur and a message may be displayed.

Sgeorge5

I disconnected the current sensor on the negative battery terminal. I no longer have problems with the load shed issue. Everything works as expected. I will judge the battery condition like in the old days, wait for a slow start, replace the battery.