Cold Weather Is Killing the Old HVBJBs

[desiato]

Just a heads up, I’ve confirmed quite a few cases of original HVBJBs failing in the past week. The cold weather tends to make the contactors stick more. If you own a 2021 or 2022 vehicle with the original HVBJB and haven’t taken it in for the 23S56 HVBJB replacement recall, you should do so immediately. Apparently, there are still many of these original HVBJBs out there that haven’t been replaced for various reasons.
...
Check your VIN here: https://www.ford.com/support/recalls/

The website lists "No Recalls" and "No Customer Satisfaction Programs" for my VIN, but I definitely never got an HVBJB replacement. I did get the OTA "recall" for it back when those went out, though. If I call up my dealer and ask for them to apply 23S56, are they going to claim it's not a recall-covered repair?

After reviewing the HVBJB FAQ, it looks like I have the following relevant DTCs, as reported by CarScanner:

• BECM
  • P0AA2(00) Archive (inactive)
    Hybrid battery positive contactor - circuit stuck open
    Status: Confirmed, Test failed since last DTC clear
  • P0D10(00) Archive (inactive)
    Status: Confirmed, Test failed since last DTC clear

I'm not sure how to interpret "Archive (inactive)" and "Status: Confirmed" both being shown.

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[GreaseMonkey]

My HVBJV failure occurred right after the recall announcement. I don’t know if it was replaced with the new part or an original.

Jack, if you have paperwork from the dealer, you might be able to tell which version was installed and cross reference with info from this forum. There’s a good likelihood you can find out one way or another. Although OEMs would use a new part number when they make a change and cascade that to their dealers.

Do you recall when your vehicle was at the dealer? I recall that I called the day of the recall, dealer scheduled my visit exactly 5 days afterwards (as instructed by Ford). My vehicle was repaired on 12/26/2023.

 

[iam-s-Hon]

Looks like I'll be in the same boat, 2021 AWD standard range, had to be towed to the dealer. charged the battery to pull codes, but couldn't drive to get it to the garage. been two days but they haven't even looked at it yet.

Call. Then call, again. Then, call some more.

Some are just not as vested in you, or think you can get by without, until you are a PITA.

 

[Js1tr3]

My 2021 Premium AWD standard range HVBJB and LVB failed and were replaced 2 weeks ago.

What did you have to do to get the dealer to do it? I have a January build date and the recal only covers eldec 2020 builds...

 

[Acadiadad]

What did you have to do to get the dealer to do it? I have a January build date and the recal only covers eldec 2020 builds...

I am still under warranty.

 

[rpr]

As a materials engineer (though admittedly mostly semiconductors, not metals), I'm a bit puzzled. There have been discussions elsewhere about Ford under-engineering the heat dissipation in the junction box. And this fits with the fact that the conductivity of metals decreases with temperature, meaning that you want good heat dissipation for good current flow through the metal contacts. The moral of this part of the story is higher temperatures = worse.

The other factor, which I'm guessing must be in play here, is contact resistance. Contact resistance does go the other direction with temperature IF you have highly oxidation-prone surfaces. But in general this is very well known and engineers design contacts with oxidation-resistant surfaces or coatings. I would expect that, if the contacts were at all properly engineered, the surely better conductivity of the metals at low temp would outweigh the possible increase in contact resistance. Did Ford really fail to engineer for the contact resistance factor completely?

(Just adding: could I be missing an important factor? The only thing that comes to mind is a much higher current draw through the contacts at low temps. I can't think of a reason the e-motors would draw that much more, and the colder it gets the more the batteries will struggle to even provide more current. Maybe I'm missing another factor?)

 

[Js1tr3]

Dealer charged for the LVB replacement and diagnostics, cleared the codes and told me to pick up the car. Sent a runner to pull around my car from the back lot and the SSN was back. Hope to find out more Monday...

 

[Mrtman]

I have a 2022 GTPE which was not included in the recall. It failed last week with the HVJB being the culprit. It was fixed under warranty this week. Picking it up tomorrow....

 

[Mach-Lee]

As a materials engineer (though admittedly mostly semiconductors, not metals), I'm a bit puzzled. There have been discussions elsewhere about Ford under-engineering the heat dissipation in the junction box. And this fits with the fact that the conductivity of metals decreases with temperature, meaning that you want good heat dissipation for good current flow through the metal contacts. The moral of this part of the story is higher temperatures = worse.

The other factor, which I'm guessing must be in play here, is contact resistance. Contact resistance does go the other direction with temperature IF you have highly oxidation-prone surfaces. But in general this is very well known and engineers design contacts with oxidation-resistant surfaces or coatings. I would expect that, if the contacts were at all properly engineered, the surely better conductivity of the metals at low temp would outweigh the possible increase in contact resistance. Did Ford really fail to engineer for the contact resistance factor completely?

(Just adding: could I be missing an important factor? The only thing that comes to mind is a much higher current draw through the contacts at low temps. I can't think of a reason the e-motors would draw that much more, and the colder it gets the more the batteries will struggle to even provide more current. Maybe I'm missing another factor?)

To be clear, it's not the cold weather itself that is damaging the HVBJBs, it's just flushing out the bad ones. HVBJB failure is caused by cumulative damage to the contacts due to poor contact and overheating. This damage is accumulated over months and years rather than a single event. Because the internal components may be warped from heat damage, they are more likely to stick when it gets cold and the clearances are tighter. The other factor with the cold is the contactor de-ice strategy, which rapidly cycles the contractors in freezing conditions to ensure they are not sticking. A damaged contactor will probably have trouble getting through a rapid cycle test. This is why the HVBJB may fail during charging initiation, producing a charge fault, and have a "Stop safely now" error the next morning. Some vehicles that never experience freezing conditions may have the deice cycle occur for the first time due to cold weather.

Here's what a burnt contactor looks like inside. This is not from a Mach-E, but is the same brand and internal design. The internal design was changed in the updated part to flatten out the contacts and eliminate a groove for better contact surface area.

 

[Sir_Blah]

This is exactly what has been happening to my car. First the 12v battery died... then less than a week later the HVBJB failed.

The thing that annoys me is that I had heard there was HVBJB recalls for some cars, but my 2021 MME (bought as a Ford certified used car) never had any recalls listed.

 

[MightyMike]

So I had mine fail right around August of 2022 (it was one of the last 2022 model year built before they changed the HVBJB. But I have heard that there have been evolution of the part since then. Is this something I need to worry about (take any active steps?)

Or is the assumption that anything other than the original HVBJB is fine.

 

[RyanMME]

The HVBJB failed in my '22 GTEPE in late December and has since been replaced. This is a buyback vehicle due to a HVBJB issue. Hopefully, the new hardware doesn't have this issue. Luckily, my car was fixed under warranty. Anyone know what this replacement costs out of warranty?

 

[PianoDan0]

I had mine replaced a year ago but my dealer is in some dispute with Ford that the recall is still open on my car, so I'm counted in that 26% when I shouldn't be.

I wonder how many cases there are like me.

 

[likescookies]

Alas, I'm in Minneapolis with a standard range RWD 2021 (thus not subject to the recall) and our HVBJB failed on Tuesday during the bitter cold. Dealer is replacing it now.

Never mind; upon further reflection, the dealer decided that the 12V was the culprit after all.

 

[ECHARGD]

Make sure you are having the problem fixed and NOT just the symptom. Did you ask for evidence that they checked the HVBJB and it is functioning correctly? Get it in writing.

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