Low voltage battery issue?

[carlk1]

Hi there I have a 2021 f150 lariat Supercrew 4wd 3.5ecoboost I purchased used from a Ford dealer that was a Blue advantage vehicle with 108900 miles . So the truck is fully loaded and has the max tow package and all the bells and whistles pretty much. I haven’t had any issues with it except for a hvac issue where the dual climate control seems to be unresponsive to temperature control. But my problem today occurred after the truck sat for approximately 36 hrs un started but the motion sensors were activated and the truck was unlocked by code and the auto- power fold of the mirrors was active . I went to start the truck today and got the kind off sound of the starter and computers waking up but it didn’t start but then after not pressing the start button again the truck started. the issue is I now have 4 alerts after this event?
1- hill hold system alert not working
2- traction control not working
3-collision avoidance system not working
4- abs / parking brake issue alert???
I currently have the truck on a battery tender and it’s fully charged however the alerts are still active.
If I disconnect the battery overnight will it erase these alerts as I haven’t had any issues with these alerts since I purchased the truck last August 15 2024. ????

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[RcFlyer330]

I would start by pulling all codes using a obd2 scanner and record them. If you charged the battery correctly (negitive lead connected to a body ground NOT directly to the battery) let it sit overnight or reset the bms. Then clear all codes go for a drive and see if any come back.

Also check the battery date if it more then 3 years old you may just want to replace it. From my experance batterys only tend to last 3 to 5 years.

 

[JohnTrigger]

Good advice above. Do all of that.

You very likely have a bad battery. Assuming original, it’s old enough and plus there were battery issues on the trucks in 2021-2022 that especially sat around for months waiting on the Covid supply chain issues.

Many on here have replaced their H6 AGM (you may have an H7 on your higher end vehicle) with (just about any name brand other than Motorcraft) H8 battery (H8 will fit except in powerboost models).

 

[carlk1]

Thanx rcflyer so I do have the negative on the battery itself since the wire stays on there all the time it’s actually on a battery tender?? Also I’m out of town on vacation so I don’t have access to my obd or forscan so that . however I do have an extended warranty and I’m currently trying to get one of the local dealers here in the oak island NC area to take a look at the truck I was just hoping that the battery disconnect could solve things ? I appreciate your your reply and input also I’m coming from a 04 Lariat into this seemingly spaceship of a truck hence my posting I suppose.

 

[JohnTrigger]

Put the negative of charger on the far end of the black negative wire that comes off of the battery where that wire connects to the truck chassis. That way you are outside the BMS sensor and it will sense that you’ve charged the battery.

 

[JohnTrigger]

That sucks while on vacation. SORRY!

And yes disconnecting the negative for say 45 min will enable all the modules to fully cold boot and (assuming simply charging battery solved what I suspect is a battery issue), the dash codes should go away but DTC codes should still be retained in memory that you can read when you get home with Forscan.

You can maybe limp the battery along (again I’m assuming your battery is on its last legs) by doing a BMS reset even on the old battery. It is one of the documented steps the Ford techs will use when trying to update software per many TSBs, if a battery won’t accept a charge enough for them to do the update. I wouldn’t just Willy Nilly do this but in your case…

Skip to about 2:15 in this video to see how to BMS reset.



I know if I were you I would simply go to AutoZone or NAPA and replace the battery and hopefully get back to having fun on the trip. If you do, also reset the BMS. The dealer will likely quickly check the battery and tell you it’s good but it still might not be and then you’ll fight with them to replace it. Not worth the hassle.

All of this assumes you have a bad battery, which is likely, but other things could have caused this….

 

[carlk1]

Good advice above. Do all of that.

You very likely have a bad battery. Assuming original, it’s old enough and plus there were battery issues on the trucks in 2021-2022 that especially sat around for months waiting on the Covid supply chain issues.

Many on here have replaced their H6 AGM (you may have an H7 on your higher end vehicle) with (just about any name brand other than Motorcraft) H8 battery (H8 will fit except in powerboost models).

t

Good advice above. Do all of that.

You very likely have a bad battery. Assuming original, it’s old enough and plus there were battery issues on the trucks in 2021-2022 that especially sat around for months waiting on the Covid supply chain issues.

Many on here have replaced their H6 AGM (you may have an H7 on your higher end vehicle) with (just about any name brand other than Motorcraft) H8 battery (H8 will fit except in powerboost models).

Thank you I’ve read that here and will definitely check that out.

Okay will do John with moving the black wire out to the location you mentioned.

That sucks while on vacation. SORRY!

And yes disconnecting the negative for say 45 min will enable all the modules to fully cold boot and (assuming simply charging battery solved what I suspect is a battery issue), the dash codes should go away but DTC codes should still be retained in memory that you can read when you get home with Forscan.

You can maybe limp the battery along (again I’m assuming your battery is on its last legs) by doing a BMS reset even on the old battery. It is one of the documented steps the Ford techs will use when trying to update software per many TSBs, if a battery won’t accept a charge enough for them to do the update.


I know if I were you I would simply go to AutoZone or NAPA and replace the battery and hopefully get back to having fun on the trip. If you do, also reset the BMS. The dealer will likely quickly check the battery and tell you it’s good but it still might not be and then you’ll fight with them to replace it. Not worth the hassle.

All of this assumes you have a bad battery, which is likely, but other things could have caused this….

okay gotcha ? and I will check that date on the battery itself and likely go ahead and replace the battery it just may be living it’s last gasp. Thanks again for the advice and tip on replacement! My previous truck which I still have was an 04 lariat and it’s like I went from a classic to a spaceship.

hey John thanks so much for the assistance and the video on resetting the bms . Also I was unable to determine the age of my battery but once I get it going I’ll stop by Napa and have them check the battery. My guess is it could be the original battery like you and rcflyer have suggested. Also I’ll let you know how things work out in the end here.

 

[JohnTrigger]

Sometimes on battery you’ll find month/year stickers on the side. Unless it is a non-Motorcraft battery in there now, I’d think that your truck is “new” enough that it would most certainly be the original. The first owner could possibly had it replaced at a dealership I suppose, but less likely.

 

[carlk1]

Hey John you’re right on spot I did find the date just now it is stamped on the top rim of the battery 11/16 20. So I’m just going to replace it with a NAPA battery I have those in my other vehicles and no issues. It is an h6 btw 760 cca the Napa is 800 I did see a Napa version of h8 with 900cca so it says it won’t fit but I’ll make the purchase in person and as long as the cable length works I’m guessing I’ll be fine. I have the neg. Cable off right now so that and hopefully the three alerts won’t reappear. Thanks for all the good advice and I’ll do the bms after I install the new battery. funny thing I always travel with some hand basic hand tools this time I didn’t and had to purchase a cheap set from Walmart but all is good and I’ll just leave them in the truck under the back seat. When I tow I have a complete set in the ttrailer and always at least have the obd2 with me? just sayin and still learning the hard way at 65 yrs old.

 

[RcFlyer330]

Yes, the h8 battery will fit but the blanket that goes around the batery will not. If you want you can purchace one that will fit from Ford it's part number KL3Z-10A687-C

 

[Henfield]

Sounds to me like the battery is likely at the end of its life. Time for a new H7 or H8.

 

[JohnTrigger]

H8 will fit, except on a powerboost. you might have to remove a cable zip tie but it’ll fit in tray and cables will stretch enough to make the connections. It is a much larger battery physically, and with more CCA and spare capacity. As far as the blanket, either slice it open and retape it in place as good as you can for now, or buy the one suggested above, or just throw it away and don’t worry about it.

FYI, I replaced my H6 proactively on my ‘24 with an H8 and bought the blanket referenced above..

 

[carlk1]

Yes, the h8 battery will fit but the blanket that goes around the batery will not. If you want you can purchace one that will fit from Ford it's part number KL3Z-10A687-C

okay rcflyer I’ll see if I can get one before I drop the new battery in tomorrow and thanks for the part number you’re awesome for getting that to me . Thanks again for all your support and inputs! This forum has been a great resource for me for sure! Hopefully the alerts come off and everystuff returns to normal and when I get back home I can look deeper into this incident. Outside of this issue the truck has been great outside of the hvac thing that when I took it to the dealer they weren’t able to reproduce the issue and the mechanic had me come into the garage and try to reproduce it and the dang thing worked perfectly while I was there ? But now I have noticed that it does work fine for the first 45 minutes before becoming a pita at that point the dials to set the temperature become useless in setting things and it will only work to warm things up on high and when it was cold out it baked us unless we went to Lo temp. So I have read on here it could be a variety of reasons for the issue and it’s not dropping off any codes for the technician. Anyway thanks again yourself and johntrigger have pointed me in the right direction!

Update : So I ended up going to Autozone and I replaced the h6 with a H7 the battery has a 5 yr. Full replacement period. But before that after having the old battery neg.cable off for several hours and previous to that having the battery tender on the old battery I reattached the cable and started the truck for the trip to Autozone. The truck did start although I did get a battery low voltage message however all the previous warnings/alerts were gone and did not reappear for the 11 mile trip to Autozone. At Autozone I didn’t even have the old battery tested and since it was almost 5ys old just went ahead and replaced it. So after replacement the truck has been immediately starting after the button push , the door locks are responding to the remote much quicker and I haven’t proven it yet but the HVAC system after the 45min. drive back to the house has functioned properly at this point ? I’ll know more when I drive back home if the HVAC system is cured? So in the end was it a failing battery that has been causing all the issues? Could it be that without the optimum voltage my truck or any of these 14 gen trucks could be prone to the issues I had been experiencing? Time will tell. In the meantime I would like to thank all those who have helped me get back to a so far normal state especially rcflyer330 and Johntrigger for all of the useful info and responses. I’ll still run the obd2 reader and forscan when I get home to see if any evidence of the issue was left behind, and go from there. but for now things are looking good and I can get back to vacation without worrying about anystuff! Thanks again and I will update again after I get back home on Sunday!! For now I can party like I’m on vacation!

 

[carlk1]

Also to answer my own question as to whether or not it was the low voltage issue ,I can pretty much say yes and since the dealers detail job on the truck was so good and the battery looked a lot newer than it was and wanting to think it would fix itself a low voltage old battery can make these spaceships do wanky things.

 

[Henfield]

H8 will fit, except on a powerboost. you might have to remove a cable zip tie but it’ll fit in tray and cables will stretch enough to make the connections. It is a much larger battery physically, and with more CCA and spare capacity. As far as the blanket, either slice it open and retape it in place as good as you can for now, or buy the one suggested above, or just throw it away and don’t worry about it.

FYI, I replaced my H6 proactively on my ‘24 with an H8 and bought the blanket referenced above..

does the battery blanket cover the bottom and the sides or just the sides?

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