Hybrid battery drain issue / ACCM update (as of 11/8/25) -- Latest info from a tech's perspective

[Edge Haley]

At the dealership I work @ we have had a Maverick in our bays for 5 weeks. It has been here 7 times in 2 years with this same problem. I have seen Fords engineers here twice and they have not yet come up with a solution.

I checked for how many components the typical Ford truck monitors when being turned on and off. The number of components is not available but the below is a general list from of a Ford website. Based on the below descriptions there may be 100 components controlled by the Maverick (or any Ford vehicle) software. It sounds like Ford diagnostics is not telling them which component is not turning off...

I'm still amazed that when I bought the Maverick Hybrid, I plugged my landscape trailer into the Ford trailer hitch and immediately got a message that my left trailer taillight was out.

From Ford website:
The computer performs a self-check on the engine, all electric motor, and related components like the battery and power take-off shaft.
Traction and Stability Systems: It verifies the operation of traction and stability control systems, which use sensors to monitor wheel speed and other factors to ensure control.
Other Systems: The computer also checks other vital systems, such as the brakes, lighting, cruise control, display, temperature controls, and most other electrical components.

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[Ken L]

Thanks for the update. It sounds like you and my dealer tech are on the same page. After the one repair, Tech followed the SSM, replaced battery, I was still getting the 'battery saver' and 'deep sleep' notifications. After another trip, they advised me that FORD were working on the issue, maybe new part (?), and the battery failed again. As long as the truck starts, they haven't replaced the battery yet.
Ironically since they then, I've only received a couple of battery saver messages. During a couple of other visits for service (un related, oil change and flat tire) , they tell me they still have the open work order and waiting for FORD.

Ken

 

[johnDeere]

I only have the problem when my interior lights do not come on when door is opened.

Deb - you can add what is called a "SAE connector to your battery under the hood. then get a trickle charger (not real expensive) with a SAE connector. Permanently have someone install the SAE connector to the hood battery posts and let the SAE cable stick out from the front grill...And plug in the trickle charger when needed...Motorcycle shops always sale SAE connectors, so does Amazon. Then all you have to do is plug it in only when needed.,,if I'm not riding a motorcycle for a month (during winter) I plug in my trickle charger.

As a software developer, I'm confident Darryl has provided the root of the problem. In software, signals are sent out to check if components are turned-On or turned-OFF. If a component like head lights or dash display screen is not sending back the OFF signal correctly that component could stay on draining the battery...the software may keep checking the device dozens of times...making the clicking sound.

It would be interesting to see if the HEAD light switch is turned to the Off position if the "sleeping" issue goes away, mine Lights are always "headlights on all the time"....some components are only turned off when turning OFF the ignition. If I leave my radio/CarPlay on and turn ignition off radio will still play and not get out of truck the software will eventually turn off CarPlay/Radio...if software does not turned off that would cause a "sleep" mode. I'd venture to "guess" that that clicking sound we all hear is the software sending software signals checking components to see if they are ON or OFF...and the software is not receiving back signals of ON...allowing that component(a) to drain the battery...I frequently hear the slicking sound an hour after turning off the truck.

I've never had the Sleep Mode problem on my 2022 Hybrid but frequently open a door and interior lights don't come on until ICE engine is turned on, and after driving just a few miles on ICE the interior doors lights start working (assuming battery has received a charge from the ICE).

Curious if the F150 has a history of the sleep mode problem also and yes they do!

Link to article:
https://www.ford-trucks.com/article...-dont-let-deep-sleep-mode-leave-you-stranded/

Thank you for your input.
if you do not have interior light come on when you open your door, the truck is in sleep mode, it started load dumping all ready.

 

[icegradner]

it's not a rocket ship - it's a truck, there is a limited universe of where the root probs can be, they have simulation software, monitoring capabilities, testing teams, many talented engineers and a lofty budget along with design and the coding teams. It should absolutely not take anywhere near multi years to figure this out.

I think the real problem lies with the mix of stuff from different suppliers. This was a real issue in the 21’-23‘ time frame, where suppliers might change multiple times due to supply shortages or work stoppages. This means testing a bunch of different configurations for the same issue, but possibly from different causes. Only Ford knows how many configurations there are, and gathering enough data from customers vehicles in a given configuration to find a solution.

Combine that with Fords unwillingness to change the charging behaviour of the 12v batteries, and you have the current problems.

For example of changing configurations, we know that Ford changed simple things like how to release the electrical parking brake in the event the truck loses power. Early production units had a pull cord under the centre console, later ones don’t and it has to be done by a different mechanism.

 

[Edge Haley]

Thank you for your input.
if you do not have interior light come on when you open your door, the truck is in sleep mode, it started load dumping all ready.

Probably right...but if I'm listening to CarPlay/Radio from battery (ICE not on) for 20 minutes if I may get a message on the screen that my battery is turning off CarPlay to preserve the battery for ICE....but truck still starts.

No doubt Ford puts out contracts for bids on components with subcontract manufacturers...and they change manufacturers for best prices. Each manufacturer may have a minor variance in manufacturing specs, especially software supported components. When any car makes changes component manufacturers detail records are maintained with effected VN Numbers with varying components.

My Honda Element had an Oxygen Sensor go bad and it sent a Error code 3456 to diagnostic device identifying what failed....any electronic component has to have an identifying number to tell a human who they are.

 

[Rceme]

We've performed the ACCM update on 4 Mavericks for battery drain. We've had success on 3 out of 4. Trust me. It's frustrating for US also.

On this one vehicle, it MIGHT drain overnight. And it MIGHT sit 2 weeks with no drain. I have performed a drain test. And it was clearly excessive. But it was quitting time. So when I fully charged the battery the next day and retested, the drain was 0.01A which is well within the acceptable 0.05A specified upper limit. Ford hotline escalated the report to the next level engineering team. Two days later they suggested disconnecting the Air conditioning control module (ACCM) and repeating the test during a high drain episode. Their conclusion was that in SOME cases the software update did not work. But they seem to think that the ACCM is still the source. Their advice was to release the vehicle to the customer. And they would be inform us when they had a permanent solution. And they are still working on a solution that will work for ALL cases.

That explains why the solution continues to be a SSM (special service message) because if a solution works in ALL cases, they usually upgrade it to a TSB (TECHNICAL SUPPORT BULLETIN).

What's the difference? From the technicians perspective , an SSM is a suggested repair. But we can try our own solution. But a TSB is something that REQUIRES us to attempt before doing something else. Otherwise they won't pay us.

So it seems that Ford was aware it would not fix every problem. But they were confident enough that it would fix a good number of them.

I treat my 2023 hybrid XLT like a plug in hybrid. I bought a battery tender 800 ma mounted it under the hood with zip ties and plug in every couple of days, seems to work.

 

[johnDeere]

Probably right...but if I'm listening to CarPlay/Radio from battery (ICE not on) for 20 minutes if I may get a message on the screen that my battery is turning off CarPlay to preserve the battery for ICE....but truck still starts.

No doubt Ford puts out contracts for bids on components with subcontract manufacturers...and they change manufacturers for best prices. Each manufacturer may have a minor variance in manufacturing specs, especially software supported components. When any car makes changes component manufacturers detail records are maintained with effected VN Numbers with varying components.

My Honda Element had an Oxygen Sensor go bad and it sent a Error code 3456 to diagnostic device identifying what failed....any electronic component has to have an identifying number to tell a human who they are.

Correct, the truck will still start with the key, that is what power saving mode does.
But try to start it with ford pass, probably not going to happen.

 

[Matso]

My former 24 Lariat hybrid had persistent battery saver mode notifications. No cause was ever identified and they spent months attempting to find one. The ACCM update did nothing. An AGM battery install likewise made no difference. So I finally threw in the towel and Ford bought it back from me for the full sticker amount. There was no way I was going to piss around with a trickle charger and go on pretending it was just an inconvenience. I made Ford accountable and they did indeed step up. Now they need to take it one step further and just fix the damn problem so everyone can move on...down the road.

 

[johnDeere]

Since this thread is so active about battery saver mode,
This is what I did to keep my 23 Mav hybrid to stop going in to sleep mode was to install a second battery under the seat.

Due to undercharging, and a too small of a battery for the load when charging stops and an issue with controllers not getting correct command stops, that all lead up to the battery drain issue.

 

[johnDeere]

From what I have read, and background from another piece of equipment with the same odd issues.

The main controller starts telling sub controller to start shutting down when you turn off the key either one by one or all at once.
And maybe one doesn’t receive the stop command correctly or something interrupts the command, and it never turns off, until the watch dog system checks and by that time the voltage is to low, and battery saver does it job and turns off its programmed controllers.

 

[Propane Burning Man]

Things have just become too damn complicated. Power everything. Why do we need, or who even requested a power parking brake. I never thought "it would be nice to not have to pull this stupid lever to engage the parking brake". Tire pressure monitoring sensors? Really? Isn't that the owners job? Yeah, back in Old School. I could go on. No going back. We are stuck with these headaches. Progress. And if you think only Ford has these issues just search for Toyotas latest recall of over 1 million Toyotas and Lexus backup camera issues, and their turbocharged V-6's blowing up.

 

[Bob zimmerman]

So I finally threw in the towel and Ford bought it back from me for the full sticker amount. There was no way I was going to piss around with a trickle charger and go on pretending it was just an inconvenience. I made Ford accountable and they did indeed step up.

I would have done the same thing. I wonder what Ford does with the truck. Do they clean it up and then resell it with the same problem? I mean, if they don’t know what’s wrong with it, how can they fix it. Maybe they just crush it?
Bob

 

[Prickly Pear]

I'll save Ford's engineers and y'all a headache by saying the drain is due to the clicking noise from the vehicle. Take care of the clicking noise and your problem goes away. Unless they are in your head then there's no cure for that.

My wife came in from the garage and told me we must have mice in the truck banging around in the engine compartment. I told her "don't worry, that's a feature!"

 

[Prickly Pear]

Do yourselves a big favor and don't let the battery run down to the point where you have to jump it (hybrid). Mine did and after jumping the truck threw what seemed like dozens of codes and went into emergency limp mode. I rolled the dice and cleared the codes after charging the battery - that was over a 1000 miles ago and no problems since (I keep it plugged in if I am not driving for a few days)

 

[mirocada]

Thanks for the update, OP.

For those who wonder why there's not a permanent fix yet, I've been watching these threads and I think part of the issue is it's not a consistent issue among the trucks with the problem. I have a '24, took delivery 1/30/24. I've had the battery drain issue twice in that time. Both times I had driven the truck the day before, so it wasn't a "sitting idle too long" issue.

To my knowledge, I"m the only owner my dealership has dealt with that has the issue. When it happened the second time, I had to educate the service department on the SSM. I've received the latest software update when it happened the second time (about 2 months ago). Fingers crossed it is the solution for me. But, if not, I have AAA for the jump to get me to the dealership.

In the "it's not just Ford" category - I ordered a Clore battery jumper to keep on hand for this issue. It was defective and I had to send it back. Cost me almost as much to ship it back as I paid for it. Go figure.

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