SSM 53801: 2022-2025 Maverick Hybrid 12V Battery Drain Issue Update Fix Released!

[SafetyGuy]

They sent me out with a new Bronco! That was a surprise for me, but the service manager said they always use new vehicles as loaners! Wow!

Score one for the good guy!

I always like a good news story!

Enjoy the new ride for the next week, and then your maverick when you get it back.

Andy

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[Darryl]

I'd like to hear @Darryl 's comment on this parasitic draw search.

The fuse box under the hood, that actually disconnects from the 12V system when you open it up to get to the fuses (and appears to feed the one inside in foot well) - is there a special tool that allows keeping that one live while it's open to access the fuses?

It that common on other models, or mainly/only a hybrid thing?
Never seen such a system.

Just curious.
Thanks.

To our knowledge, there’s no way to keep the circuit live. This is most frustrating for us techs since the instructions for finding a draw STILL tell us to remove fuses one at a time. This system is used the All mavericks as well as several other cars. And it just as frustrating on each of them . Hopefully the reprogramming of the ACCM will fix the parasitic draw

 

[HeyBales]

To our knowledge, there’s no way to keep the circuit live. This is most frustrating for us techs since the instructions for finding a draw STILL tell us to remove fuses one at a time. This system is used the All mavericks as well as several other cars. And it just as frustrating on each of them . Hopefully the reprogramming of the ACCM will fix the parasitic draw

Yikes.
I guess there are some "mini" style clamp meters.

But still, now a chart of all the wires in a huge bundle.
Hopefully a location where the protector can be removed to spread them all out.
And good enough eyes/light to see the colors and hope they aren't repeated.
What a nightmare.
Perhaps everything in that fuse box (power distribution?), has amp readings that appear in the OBD2 readings somewhere. I'm guessing it's not that simple though.

 

[skinnyboy]

To our knowledge, there’s no way to keep the circuit live. This is most frustrating for us techs since the instructions for finding a draw STILL tell us to remove fuses one at a time. This system is used the All mavericks as well as several other cars. And it just as frustrating on each of them . Hopefully the reprogramming of the ACCM will fix the parasitic draw

Wow, dummy me never made the connection about that aspect of the design when looking at the fuse box. How can Ford expect you to troubleshoot circuits like that?

Cheers.

 

[Darryl]

Wow, dummy me never made the connection about that aspect of the design when looking at the fuse box. How can Ford expect you to troubleshoot circuits like that?

Cheers.

I guess they think we’re magicians.

 

[pennmaverick]

For those outside of warranty period, call the Ford Corporate number and open a case. They will reimburse you or the dealership to perform the software update. It was a pain in the neck, but worthwhile if indeed this fixes the 12v draw. My dealership did not have any problem applying the update.

Edit: They were not transparent with the reimbursement process. Turns out that you share in the cost of the software update, but no one told me that until after the dealership processed the software update. Then the dealership wouldn't release my vehicle because Ford corporate was having some kind of system issue and the dealership couldn't obtain the approval even though they already did the work. So the Maverick was stuck at the dealership another day and the customer is forced to call and be the go-between between the dealership and corporate. Ford continues to impress. :-(

Edit Edit: In the end, Ford corporate paid for it. No explanation about why the above didn't seem to apply. I needed to follow up with a second rep just to get the process completed.

 

[CD_SM]

Has anyone who has had the problem tried always turning off the HVAC completely every time before they turn off the truck? That was discussed as a possible reason for some of us not having the problem, or for having seasonal problems, earlier in the thread. (Sorry if it's been answered already, I haven't read all 12 pages of replies.)

 

[johnDeere]

Has anyone who has had the problem tried always turning off the HVAC completely every time before they turn off the truck? That was discussed as a possible reason for some of us not having the problem, or for having seasonal problems, earlier in the thread. (Sorry if it's been answered already, I haven't read all 12 pages of replies.)

When my truck started to deep sleep, and I read that it may be the AC system, I started all the combinations of things turning on and off to see if it changed the deep sleep when I turned off the truck.
It looks like to me from viewing a volt, amp meter connect to the battery, is that there is something that does not get shut off in a timely manner, when the truck is turned off.
(I have seen power drain of 3-4 amp for 4 hours after the truck was turned off.)
I am not seeing the drain happening on and off during the day, just when I turn off the truck.

 

[CD_SM]

Wow, dummy me never made the connection about that aspect of the design when looking at the fuse box. How can Ford expect you to troubleshoot circuits like that?

Cheers.

Two thoughts:
1. I am willing to bet lunch (but not dinner!) that this is one of the reasons why Ford hadn't found and fixed this earlier. Just as hard for them.
2. Ford's engineers almost certainly did this for a reason. My guesses are either for safety if there are a lot of amps (Q: does anything from the HVB come through that block?), or (more likely) to protect sensitive electronics that could be zapped by arcing when putting or pulling a fuse the normal way. IOW another example of the law of unintended consequences.

 

[johnDeere]

Two thoughts:
1. I am willing to bet lunch (but not dinner!) that this is one of the reasons why Ford hadn't found and fixed this earlier. Just as hard for them.
2. Ford's engineers almost certainly did this for a reason. My guesses are either for safety if there are a lot of amps (Q: does anything from the HVB come through that block?), or (more likely) to protect sensitive electronics that could be zapped by arcing when putting or pulling a fuse the normal way. IOW another example of the law of unintended consequences.

There is no HVB voltage coming to that fuse block.
The fuse block under the hood does not have lots of high amp items, the only high amp is for the electric heater.
Who knows why they did it this way, maybe since nothing is written on the cover or the block, its easier to unplug it and take it inside to see it under the kitchen light?

Its possible they did it that way as you mentioned, (safety reason), with the truck in ready mode, the DC to DC converter has the potential of supplying over 200 amps of 12 volts.

 

[BlueSpec1]

12V BJB design might be for space savings. I see they're in the Escape & Maverick, gas & hybrid.

High Voltage ~300VDC doesn't go thru the BJB.

414-03 High Voltage Battery, Mounting and Cables Description and Operation 2023 - 2024 Maverick
The high-voltage system consists of the following components:
• High-voltage battery cable
• Inverter System Controller (ISC) also known as the SOBDMC
• Electronically Controlled Continuously Variable Transmission (eCVT)
• Direct Current/Direct Current (DC/DC) converter control module
• ACCM and A/C compressor assembly located on lower LH side of the engine block
• High voltage battery pack

 

[MavTime]

THIS ^^^^^^^^

My 23 hybrid has had deep sleep since the beginning, I have held off on all updates and recalls, but I am still on my original flooded battery. I have about 10k miles, and I have an in-car NOCO 2A charger/maintainer connected that I use to top off periodically. I have the Noco connected past the negative terminal sensor so the BMS should be seeing and registering the charge. I don't bother resetting BMS every time since it should be detecting the change in voltage from the charge. Well after a weekend of charging, it then drove fine Monday, but Tuesday morning was my first totally dead Mav ever.

So I jumped it and then trickle charged for 8-12 hours, then I did the "full" BMS reset in the manual which includes waiting 8 hours (the manual isn't clear that both need to be done for the system to detect true voltage levels). In the morning with the Mav in drive mode my cigarette lighter USB charger voltage readout showed 12.6 volts (not charging) for the first time vs the 14.6 volts (charging) that I generally see when the car is on and in drive mode, I think that was a good sign as the car wasn't trying to charge the battery since it was charged. Now my readings at the battery with a DMM match what the USB charger says. I know my original battery is likely cooked at this point, but over the coming long weekend I am going to let the NOCO charger fully charge AND recondition the battery to solid green and do the "full" BMS reset again and wait 8 hours and see how long I can go with my old battery and my short trip driving before I get deep sleep again.

Could it be that the BMS gets out of sync, either by normally driving/charging, or externally charging over time? I think Ford is focused on small voltage draws that could be a minor layer to the problem, but I think the main problem is the Mav isn't charging the 12v battery enough possibly due to BMS protection or BMS not knowing the true charge of the battery. 2Gen Prius had a similar 12v set up but without this "smart" BMS and their AGM battery would last 8 years even with always-on voltage draws like the key fob receiver. I hope someone who drives short trips can report back after getting this new service bulletin performed and have positive results.

Update after charging on the 2A Noco charger/maintainer for 5-6 days without driving or disconnecting. The Noco was flashing red when I checked it this morning, no interior lights, and USB charger voltage meter said 11.9v before turning on the car, it did turn on. I did notice the Air/Con was OFF but the fan was on upon starting the Mav. So seeing that I did fairly recently got the Noco to get to flashing green (conditioning after fully charged), maybe there is something related to the ACCM even though I just had Fan only on, or my battery is damaged beyond Noco repair. I'll try making sure everything is off before turning car off and try charging and see if it goes green.

 

[HeyBales]

Two thoughts:
1. I am willing to bet lunch (but not dinner!) that this is one of the reasons why Ford hadn't found and fixed this earlier. Just as hard for them.

It certainly explains why this SSM, before it was rewritten with a solution, seemed to cut off all parasitic draw troubleshooting - just reset, test battery, inform of upcoming software solution.
Basically, stop spending time on it.

Which means the few posts that included info where the tech did do parasitic draw troubleshooting - gave the Ford instructions on just removing modules to see if it effected the draw.
Always thought that sounded strange - but they had no other way since I think those are mainly fed from the underhood BJB.

You could do the better troubleshooting on the footwell one, but now down to subsystems and sensors.

I'm still wondering about the 2 posts I recall both being about the TCU module being replaced because it had the problem. Not the ACCM. But time will tell.

 

[23OxOrdered]

2nd battery replaced 05/27/2025 on my 2023 with ACCM Software update i am hopeful new hardware (battery) and software update will contribute to fix!

My Service tech notes on invoice:
===
Customer concern verified. Vehicle goes into Deep Sleep Mode when not driven for 2 days.
Found SSM53801 that is applicable
Performed Battery Diagnostic test: BATTERY FAILED , ACES code: H898P, DTC Code 1BJXJA100LP5
Removed / Replaced battery, Reset BMS, Performed ACCM SOFTWARE UPDATE, Cleared DTC's.
Vehicle no longer in deep sleep or BATTERY SAVER MODE
Customer Concern Resolved (i am so hopeful!!!)
===
-I pulled fuse (trucklette still slept like a baby)
-driving every day or not for 2 day (trucklette still slept like a baby)
-warm or cold weather (trucklette still slept like a baby)

 

[Darryl]

There is no HVB voltage coming to that fuse block.
The fuse block under the hood does not have lots of high amp items, the only high amp is for the electric heater.
Who knows why they did it this way, maybe since nothing is written on the cover or the block, its easier to unplug it and take it inside to see it under the kitchen light?

Its possible they did it that way as you mentioned, (safety reason), with the truck in ready mode, the DC to DC converter has the potential of supplying over 200 amps of 12 volts.

They do this on all vehicles on this platform (Maverick, Escape, bronco sport) . It's just a different design probably saves Them money in production

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