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The Mystery of Ford’s Battery Management System Revealed

Yes, I am an owner of a car repair shop. But even after 15 years I’m still learning about technology in today’s vehicles as it’s changing all the time!  This week my  journey takes us into the Battery Management System on my own 2016 Ford Escape.    

Being observant about changes in your vehicle is as important as noticing changes in your own health. And just as important is not ignoring those signs. A few days ago my car started shutting down the radio and dash almost immediately after turning off the vehicle. In the past it would stay on for a very long time so I could continue to listen to the radio or finish up a phone call unless I opened my car door. And then I noticed a message on my Ford Escape SYNC screen, “System Off to Save Battery… turn ignition off or start engine”.  Thoughts flooded my mind – Does this mean my battery is failing? Is my battery charging properly? Does it just need serviced? I’m not having starting issues, so what does this mean?

I’ve got access to Ford techs, but not everyone has that, right? Since I enjoy learning, I did a deep dive into the world of Internet as you might. It was simple to find various opinions on YouTube but factual data from Ford on this topic was in short supply. Why? Today’s vehicles require the proper knowledge and electronic tools to perform most services. Manufacturers would like you to use their dealers, but that is not usually required. A shop with up-to-date tech training and the proper electronic tools can also perform these services.

What I did learn was that this SYNC message relates to the BSM – Battery Management System, sometimes also referred to as Battery Monitoring System/Sensor. The rest of the information made my head spin and confirmed that the Internet can lead to debates and false information.

I’m familiar with the Control Module term. A quick conversation with our lead tech, and I learned we perform those battery resets routinely in our shop with a scan tool or the Ford IDS program computer. I’ll make an appointment to have my battery and connections tested – yes, even “The Boss” makes appointments!

I can remember how simple it used to be to change a car battery. [My age is showing.] It used to be right up front in the engine compartment and easily accessible. Now you’re lucky to find it, hidden under plastic covers and behind or below other components!  There are YouTube videos to tell you how to find the battery in your vehicle, so there’s a clue that times have changed. I’ve seen our techs disassemble the front of a vehicle to replace a headlamp bulb - I don’t know why I’m surprised by any of this.

So that you can get a quick visual of this evolution, I’ve selected a car that’s been around a while – the Ford Mustang – and created a timeline. Can you tell when the battery disappeared in these images?

As you can see, the engine compartment from 1967 – 1984 is very similar. In 1996 you see a huge jump in technology, which then takes another giant leap in the next decade. I personally sympathize with those of you who remember how vehicle ownership used to be. Today’s vehicles are much more complicated, expensive to purchase, and a significant investment to maintain. From a repair shop standpoint, it’s also expensive and time consuming to ensure our techs have the latest training, tools and computer resources to continue taking care of your newer vehicles.

I wanted to share with you some of what I gleaned from my online research that is fact rather than controversy, so if you like technical subjects read on! [If not, you can jump to the Summary, but you did read the Title of this blog and kept going...]

“BMS = Battery Monitoring System, the suite of sensors, electronic modules and computer program that determine battery condition and provide data to other systems which manage the charging rate and load-shedding (battery saver) features...”

“Battery Replacement - If the vehicle battery is replaced, it is very important to perform the battery monitoring system reset using the scan tool. If the battery monitoring system reset is not carried out, it holds the old battery parameters and time in service counter in memory. Additionally, it tells the system the battery is in an aged state and may limit the Electrical Energy Management system functions.”

“… The BMS data is held in non-volatile memory (it is retained even when the battery is disconnected) and cannot be reset by any means other than use of an appropriate tool plugged into the diagnostics port on the car to send the correct 'BMS reset' command-code to the Body Control Module (BCM).”

In summary, even among Ford online forums you will find conflicting answers about whether a BMS reset is needed, how it is properly done, “cheats” or work-arounds, partial resets, and the unknown - what happens if you don’t perform a reset at all. Personally, I don’t like to take risks when it comes to potentially expensive repairs and my vehicle that I rely on daily. My recommendation would be to have your Ford’s services performed at a trustworthy, up-to-date shop where trained professionals can, if needed, do the battery replacement and proper reset. That way you’re not voiding any warranty or risking damage to the other charging components. If we can be of assistance to you, call our Service Team at I-86 Truck & Auto Repair or request an appointment online.

My conclusion? The battery in my Ford Escape is a pain to remove and replace to begin with, involving removing covers, wire harnesses displacement, removal of air filter and air box, standing on my head to reach into the back of the engine compartment… or removing the windshield wiper arms, tiny clips to lose, taking off the cowling and its drain pan and still out of reach. Now that I have a further understanding of vehicle technology from this journey, it suddenly does not seem so “expensive” and “inconvenient” to have a repair shop do this for me. If given the opportunity I would certainly give manufacturer engineers some “feedback” on behalf of vehicle owners everywhere! And you’ll want to be extra kind to the auto techs you know because they work harder than ever.


Ronda Whitford, Owner

I-86 Truck & Auto Repair

1739 Lindquist Drive

Falconer NY 14733