Pebbles theIt’s not that the change can’t complete within 12 minutes. The HV to LV converter will be active for 12 minutes after shutdown so the process of disconnecting the battery cannot start until 12 minutes after shut down.
and I are going to have a chat and come up with some CAUTION wording and make a sticker or stencil it on the trim piece over the battery. I suppose it’s possible this fix was created without considering secondary unintended consequences…but I guess I’d rather believe Ford engineers and project managers are up to the task and through testing determined the risk is minimal. But, that might be wishful thinking…
Yes, I understand that, my point is how is this a concern for anyone. Under what circumstances or situations would anybody be accidently racing to disconnect the 12V battery within 12 minutes after shutting down the vehicle causing this failure. And this especially applies to automotive service centers, whether dealer or independent. If one started working on your vehicle within 12 minutes of you shutting down your vehicle, it'll be the first time in history that ever happened. Unless the car's on fire, a mechanic is not digging into your car within 12 minutes of you getting out of it. I apologize if my initial post was unclear, but I think you get what I'm saying here.It’s not that the change can’t complete within 12 minutes. The HV to LV converter will be active for 12 minutes after shutdown so the process of disconnecting the battery cannot start until 12 minutes after shut down.
Interesting, this is how GM vehicles work, but they can actually keep the HVB live for up to 20 minutes in the heat (cooling the battery, inverters, converters and the motors as necessary). The GM owners manual has the same warning about checking the 12V level before disconnecting it.The 12V lockout recall software (25S65) has been released for all Mach-E's as of today. You can now schedule to have it installed at your dealer if you have a '21-24 vehicle. The update will take the technician about 30 minutes to apply. I've already installed the software on my car, and as expected:
- The charging system will maintain 14.5V for 12 minutes after vehicle shutdown.
- If the 12V battery were to fail while driving, the DC/DC converter will continue to provide power to the door latches through the 12-minute post-shutdown period, allowing unlock and entry/exit.
After the update, you may notice the slight hum of a cooling pump running after driving and parking the car (if it's warm outside). This is normal, it is cooling the DC/DC converter producing the 12V power. If it's cool outside, the vehicle will be silent with no indications the 12V is actively charging. The high voltage system now stays energized during the 12-minute post-shutdown period. After 12 minutes have elapsed, you will hear two successive clunks, which are the main high voltage contactors in the HVBJB opening.
This update will also be beneficial if you drive many short trips (<10 minutes), because you will have additional 12V charging time after shutdown. This will help keep the 12V battery charged up, and covers the load of headlights, screens, and opening/closing doors during the post-shutdown period. Before, all those accessories would drain the 12V battery by about 5-10% after each shutdown.
One important service change—if you are replacing the 12V battery from now on, you will now need to wait at least 12 minutes after the vehicle is shut down before removing the battery terminals. The charging system will remain powered up (and may be silent). If you don't wait 12+ minutes, you could short out the DC/DC converter or blow a mega fuse if the positive cable touches ground, even after removing the negative terminal. Terminal voltage should be less than 13V before removal.
You probably do not want to use that switch while the battery is being charged. Make sure the voltage is below 14V before using that switch or disconnecting a cable.I have a 12V LVB disconnect switch installed. This was intended to facilitate the 'hard reboot' scenario where the car has gotten itself 'logic locked' (or just plain stupid) and needs to be completely powered down for a "time out" until it comes back to it's senses and will behave.
So when I press the remote to kill the LVB it will now take up to 12 minutes (from whenever I shut the car off with the Start/Stop button) for the car's 12V systems to de-energize. It's just something I'll have to keep in mind.
If the battery dies while the car is running around doing errands....and the DCDC converter is still providing power to the systems....does that harm anything?
Please show me where @Ford Motor Company posted any of @Mach-Lee ’s detail as to what the recall actually does.
I"m guessing not since the systems don't care where they're getting power from, just they are getting sufficient power. It's like when an ICE has a battery die while the engine is running. You don't really know when the battery died, just that you can't start it after shutting it off. Well, unless the power coming from the DC-DC converter is noisy/dirty (highly unlikely), which could cause signal corruption on comms lines.
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My general observation is that the car doesn't drain the HVB very much at all when on provided you don't have the heater on, and to a lesser degree the air conditioning. And BTW I have noted that when is "Accessory mode" the air conditioning is reduce quite a bit, so it probably draws even less in that mode.
The process I use for changing the 12V battery (one time so far!) is 1) shut down, 2) open hood and get various tools, 3) remove a bunch of plastic covers, 4) loosen the cross support bar over the battery and move it out of the way, 5) remove the battery hold down bar, 6) remove battery terminals, ... Steps 1-5 will take me about 12.5 minutes, so I am safe.
Yes, you would need to wait before disconnecting the 12V.
