Let's talk about my HVB woes...

[Ranko Kohime]

Fake "Tow Champ" all BS!!! It's the internet.. I can be a " Heavy Hauler" too.....

Like a Rock
I was as strong as I could be
Like a Rock
Nothin’ ever got to me
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[icegradner]

Like a Rock
I was as strong as I could be
Like a Rock
Nothin’ ever got to me
Like a Rock

This an't no Chevy forum man!

 

[BoboysTruck]

I had(have) this issue. I have 150k miles on my 2022 XLT.

I used to drive my Mav alot for work and had no problems, zero. No deep sleep, no dead Hybrid, nothing. Then May 2024, my wife started driving it, 20 miles to/ from work 4 times a day. The engine temp would barely get up there so I thought might be a good idea to drive it in SPORT mode.

I don't know if that had anything to do with it over time but P0B24 started showing in April 2025. It has come up 7, maybe 8 times since. I just cleared the code every time. The last time it happened was May this year at 144k miles. It's at 150k now.

I also have the ongoing dead Hybrid issue. Voltage at the battery post would be 12.6V but only around 4 under the hood. I don't believe it's the cable because I have replaced the cable terminal under the hood and continuity testing shows almost 0 every time.

Please update if you ever figure out the cause of your P0B24 issue. Thank you.

 

[icegradner]

I had(have) this issue. I have 150k miles on my 2022 XLT.

I used to drive my Mav alot for work and had no problems, zero. No deep sleep, no dead Hybrid, nothing. Then May 2024, my wife started driving it, 20 miles to/ from work 4 times a day. The engine temp would barely get up there so I thought might be a good idea to drive it in SPORT mode.

I don't know if that had anything to do with it over time but P0B24 started showing in April 2025. It has come up 7, maybe 8 times since. I just cleared the code every time. The last time it happened was May this year at 144k miles. It's at 150k now.

I also have the ongoing dead Hybrid issue. Voltage at the battery post would be 12.6V but only around 4 under the hood. I don't believe it's the cable because I have replaced the cable terminal under the hood and continuity testing shows almost 0 every time.

Please update if you ever figure out the cause of your P0B24 issue. Thank you.

If it’s not the battery cable from the DC to DC converter to the 12v battery issue from the customer satisfaction program, then you must have bigger issues. I would still test that battery cable, but given the mileage you put on, I suppose it could be simply the HV is wearing out. Considering all the supply issues in 2022, who knows what we ended up with in these early production Mavericks.

 

[BoboysTruck]

If it’s not the battery cable from the DC to DC converter to the 12v battery issue from the customer satisfaction program, then you must have bigger issues. I would still test that battery cable, but given the mileage you put on, I suppose it could be simply the HV is wearing out. Considering all the supply issues in 2022, who knows what we ended up with in these early production Mavericks.

I never thought of the cable from battery junction under the hood to the DC to DC CONVERTER as a possibility. Maybe that was mentioned here. But I will definitely check that. Thank you so much for mentioning that.

Let me share something crazy that I discovered by accident. After I replaced the battery cable terminal a few months ago and put it back together, the Mav still did not start. I disconnected the two big cables to the fuse box, measured voltage to the terminal i just replaced and was getting 12.xx V. As soon as i reconnected one of the two big cables, the voltage to the cable terminal would drop.

Anyhow, I put everything back together and was retightening the nuts to the battery cable terminal when I accidentally touched the DC to DC CONVERTER. It caused a spark and somehow, THAT WOKE THE MAV UP! ALL THE NORMAL CLICKING YOU HEAR THE HYBRID MAV DOES STARTED!!!

When it wouldn't start last week, I tried that. Voltage at the battery post was 12.6V but only 4.xx V under the hood.
I used a multimeter cable. I put the probe end to the positive terminal and very quickly touched the DC to DC CONVERTER. This causes a spark of course but yes, it woke the MAV up again.

You think this means I have a bad DC to DC CONVERTER?

 

[icegradner]

I never thought of the cable from battery junction under the hood to the DC to DC CONVERTER as a possibility. Maybe that was mentioned here. But I will definitely check that. Thank you so much for mentioning that.

Let me share something crazy that I discovered by accident. After I replaced the battery cable terminal a few months ago and put it back together, the Mav still did not start. I disconnected the two big cables to the fuse box, measured voltage to the terminal i just replaced and was getting 12.xx V. As soon as i reconnected one of the two big cables, the voltage to the cable terminal would drop.

Anyhow, I put everything back together and was retightening the nuts to the battery cable terminal when I accidentally touched the DC to DC CONVERTER. It caused a spark and somehow, THAT WOKE THE MAV UP! ALL THE NORMAL CLICKING YOU HEAR THE HYBRID MAV DOES STARTED!!!

When it wouldn't start last week, I tried that. Voltage at the battery post was 12.6V but only 4.xx V under the hood.
I used a multimeter cable. I put the probe end to the positive terminal and very quickly touched the DC to DC CONVERTER. This causes a spark of course but yes, it woke the MAV up again.

You think this means I have a bad DC to DC CONVERTER?

I know when the customer satisfaction program replaced the cable from the converter to the 12v battery was done, they also replaced one of the big fuses under the hood. Apparently that was a common issue in early production, a faulty fuse, I remember the tech noting a bunch of pin testing. I do not recall which one, when I get a chance I'll look at the paper work from 2023.

Edit found the paper. The tech noted replacing a 300 amp high current fuse after finding DTC U30003:64 in the DC/DC module. This was covered in SSM 52024.

 

[GreyCacti]

This is the 3rd hvb issue I read Tonight.
What drive mode do you use most?
Do you feel that using the truck a certain way it's killing the hvb?

 

[Suzukiridr14]

As some of you may have read here, I am a heavy hauler, and have already had the HVB on my '25 replaced, at 99k miles. I type this now with 190k miles on the clock.

This thread is a brain-storming thread, because at this point I can't quite wrap my head around the behavior.

First, the 12V: I am not going to discount the possibility of the 12V causing some of what I am seeing, but I will note that I have the telematics module (fuse 11) disabled, as such I do not use the Ford app, and touch buttons on the handles have worked flawlessly except for one ultra-dewy morning in which they either wouldn't lock or wouldn't unlock, it's been a while, I forget. No other issues, and I never let the truck sit.

As for the HVB, my initial problem was sudden, abrasive loss of regen braking: instead of a smooth roll off of battery current, it simply dumped, causing a feeling of something breaking, and a need to apply more brake pedal to stop. This was shortly followed by an extremely small electric window (on the EV coach screen), resulting in a near inability to accelerate on battery alone.

Adding HVB voltage to my ScanGauge III display revealed that voltage was rising rapidly during regen, and falling rapidly during acceleration, reaching 250V and 190V respectively.

This went on for a number of miles until it finally set code P0B24 (Hybrid Battery A Voltage Unstable) (youdontsay.gif) at which time I took it in, and the battery was replaced.

I maintain that the battery was not, and is not, the cause of my troubles, and at the time, I theorized that it was the contactor (a type of relay used for high amperage HV applications like electric power trains) to blame, as the behavior would come and go, and sometimes a simple power cycle would reset the issue.

For those unfamiliar with Lithium batteries, they tend to go BOOM if there is a real problem internal to the battery, or a cell.

Fast forward to roughly 135k miles, and the problem makes a reappearance.

A nuance that I did not see, so I cannot tell if it was occurring on the first battery, is that the State of Charge (SoC) is getting wildly out of sync with the actual battery on cold starts, and even rarely on hot starts. Note that this is HVB SoC, not 12V SoC. I had one occasion where I drove to a store, shut off with ~45%, restarted to being at ~28%, forcing a recharge cycle while I drove around the store, shut off again to restart with above 70%. I am not recalling the voltage from this particular incident.

As of late, it has been doing the screwy business of randomly jacking the SoC up when shut off for a number of hours. I can say with a great deal of confidence that if the battery voltage is 210V, that I am not at 80% SoC, which yes, I have seen. I am going to start tonight logging shutdown and startup screens from my SG to see the difference.

I am rather stumped now as to guessing the actual problem. It seems like the HVB BMS is faulty, but is it a physical fault, or a software bug?

I joined the Blue Oval Labs Discord that was linked here, but I am forgetting by who, and I am somewhat bewildered by the array of projects and channels going on, so I am not sure if any work being done there would be relevant. I do have ForScan, but I do not know which module is the HVB BMS or how to show individual cell voltages, if that is supported by it.

Anyone have any ideas? Should I go get a used Tesla pack and bolt it on to make the problem worse?

At this point, I would trade in my Maverick and start from square 1 with another Maverick. Any vehicle that went 190K miles, owes me nothing, served me well, and deserves to retire!

 

[HeyBales]

I never thought of the cable from battery junction under the hood to the DC to DC CONVERTER as a possibility. Maybe that was mentioned here. But I will definitely check that. Thank you so much for mentioning that.

Let me share something crazy that I discovered by accident. After I replaced the battery cable terminal a few months ago and put it back together, the Mav still did not start. I disconnected the two big cables to the fuse box, measured voltage to the terminal i just replaced and was getting 12.xx V. As soon as i reconnected one of the two big cables, the voltage to the cable terminal would drop.

Anyhow, I put everything back together and was retightening the nuts to the battery cable terminal when I accidentally touched the DC to DC CONVERTER. It caused a spark and somehow, THAT WOKE THE MAV UP! ALL THE NORMAL CLICKING YOU HEAR THE HYBRID MAV DOES STARTED!!!

When it wouldn't start last week, I tried that. Voltage at the battery post was 12.6V but only 4.xx V under the hood.
I used a multimeter cable. I put the probe end to the positive terminal and very quickly touched the DC to DC CONVERTER. This causes a spark of course but yes, it woke the MAV up again.

You think this means I have a bad DC to DC CONVERTER?

Sounds like that's the equal to going to On position on the keyed trucks.
The HVB is enabled for powering the 12V system and charging battery - until the HVB SOC reaches 30%.

Or you mean it really went to Ready mode, which of course is On mode plus ability to start ICE when needed.

Perhaps you have an unreliable ground, you touching the DC/DC metal housing is giving that needed ground.

 

[HeyBales]

I had(have) this issue. I have 150k miles on my 2022 XLT.

I used to drive my Mav alot for work and had no problems, zero. No deep sleep, no dead Hybrid, nothing. Then May 2024, my wife started driving it, 20 miles to/ from work 4 times a day. The engine temp would barely get up there so I thought might be a good idea to drive it in SPORT mode.

I don't know if that had anything to do with it over time but P0B24 started showing in April 2025. It has come up 7, maybe 8 times since. I just cleared the code every time. The last time it happened was May this year at 144k miles. It's at 150k now.

I also have the ongoing dead Hybrid issue. Voltage at the battery post would be 12.6V but only around 4 under the hood. I don't believe it's the cable because I have replaced the cable terminal under the hood and continuity testing shows almost 0 every time.

Please update if you ever figure out the cause of your P0B24 issue. Thank you.

Sport mode's goal (like Tow mode) is keep the HVB closer to 70%, than the normal hovering around 50%.
And a much tighter range than normal 30-55%, I think I rarely saw Sport go below 60% during normal driving that just wasn't needing the assist of the EV constantly. Actually towing would allow that to go lower which is the purpose of hanging around 70%.

I drive 5-6 miles to work, with majority of that being highway - in the coldest temps I get up to 185F coolant no problem - that's about middle of gauge range.
How high is it getting on her 20 mile trips?
Are they city driving slow and lots of EV usage?

 

[Ranko Kohime]

I had(have) this issue. I have 150k miles on my 2022 XLT.

I used to drive my Mav alot for work and had no problems, zero. No deep sleep, no dead Hybrid, nothing. Then May 2024, my wife started driving it, 20 miles to/ from work 4 times a day. The engine temp would barely get up there so I thought might be a good idea to drive it in SPORT mode.

I don't know if that had anything to do with it over time but P0B24 started showing in April 2025. It has come up 7, maybe 8 times since. I just cleared the code every time. The last time it happened was May this year at 144k miles. It's at 150k now.

I also have the ongoing dead Hybrid issue. Voltage at the battery post would be 12.6V but only around 4 under the hood. I don't believe it's the cable because I have replaced the cable terminal under the hood and continuity testing shows almost 0 every time.

Please update if you ever figure out the cause of your P0B24 issue. Thank you.

Sport mode shouldn’t be affecting it, neither should the short drives. Those are harder on the engine than any other powertrain component.

I don’t know the full path of the 12V circuit, but, in similar fashion to what I suspect is at issue with the HVB, for you something in the chain between battery and power consumer is bad.

Aren’t electrical gremlins fun?

 

[Ranko Kohime]

At this point, I would trade in my Maverick and start from square 1 with another Maverick. Any vehicle that went 190K miles, owes me nothing, served me well, and deserves to retire!

It owes me a million. It is a work truck, after all.

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