"System Off to Save Battery" appears while driving after 3.4 upgrade

Thanks for the info, I don’t think they’re original, they say “rural king” on them if I’m thinking of the same brand they’re a fairly cheap battery (quality) I’m going to AAP and AutoZone have them bud for lowest battery price if I need new ones. Lol. I’ll keep the post updated

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I would say bargain basement to be nice…

Probably purchased at tractor supply LOL… the truck came from florida. So anything is possible

Auto Batteries - Batteries & Accessories - Automotive & ATV - All Departments (ruralking.com)

Who Makes Rural King Batteries? and Battery Warranty - HotVehs.com

Maybe you can apply for warranty depending on the battery model.

BECM has nothing to do with it. That module is there to provide power to the Air Bags for circumstances when the vehicle is not on or moving.

Do you have information on the BECM module?

That’s from the Ford service manual. It explains what the BECM is for. I have one sitting here also if you want a pic of it. If you look it up in wire diagrams you can see where it has 2 power inputs and than 2 outputs that feed the RCM and Supplemental Restraint System power. So basically if someone is sitting inside a parked car turned off and it gets hit that module will provide power to deploy airbags and what not to protect the occupant.

I’m having this same error in my 2015 F150 which I upgraded from Sync 2 to Sync 3 and then to v3.4.21194 also. Before I start throwing batteries and alternators at it, I’m curious if the update might b the culprit. I have a 2015 Mustang where I did the same hw/sw update with same version, and no issue with this message. Help!

All the ideas regarding this specific issue are on this thread, now it’s up to you to try any of them to see if they make any difference.

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How old is your battery? OEM AGM batteries in the newer vehicles today average 3.5 to 4.5 years depending on location in the US. EU and others are probably close to this also. Some brands do better than others. Keep in mind also that the newer software versions for Sync have improved and fixed things not working before, especially in Sync 3 retrofitted vehicles, although I am sure that was not Ford’s intention. Messages like this now actually work.

The best thing to do is to test the battery and charging system on the 2015 F150 to see if it needs service. With a vehicle of this age, it would be recommended to do so anyways. Some places do it for free, some charge a little. If you find you need a battery during the test, it’s better than finding that out 2 hours from home on a cold night.

I disconnected all the bolts and nuts at the terminal, cleaned all connections and then tightened everything back down. Been driving all day, no issues, no DTCs etc. must’ve been bad connection somewhere. So the message was accurate when it came up. All is good, still running 21194. So I guess check all your wiring and terminals double check they’re good. I had batteries and terminals of numerous times so I could’ve left something loose. Had 3 places test batteries and charging system all came back good except the first one before I fixed all connections

Excellent, thanks for the feedback.

The battery is a Walmart EverStart Maxx Lead Acid 800 CCA from 8/18. **One thing I notice is that the HVAC controls backlighting I noticed will sometimes be on after I exit the truck. Only that section of dash lights. All cables and terminals look clean and havne’t been touched in the few months I’ve owned the truck and done a little Forscan coding plus the apim/screen swap.

That is not listed as an AGM battery. Walmart website says it is not compatible for the vehicle. It does have a 3 year warranty.

That said, if the BMS (Battery Monitoring System) was not adjusted for the SLA vs. AGM type battery, the SLA will never charge past 90%, probably lower, and not at optimum rate. Over time this will damage the SLA battery and decrease the lifespan of the internal materials. The F-Series trucks use AGM batteries which are referred to in some circles as deep cycle batteries. Normal SLA batteries are no longer used as they do not have the discharge capacity over time to support the advanced electronics and features in these vehicles with higher discharge rates.

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Definitely helpful. Thanks for weighing in.