He's dead Jim! Whodunit? 12 V or HVBJB, place your bets!

[dtbaker61]

I understand how distributed systems work, that's pretty much been my technical field my whole career. Not embedded, but server side, be that supercomputer or large (geographically) distributed data systems.

I'm not in embedded systems, and I understand there is a difference between aircraft/automotive and consumer/enterprise gear. And yet, 250 watts is still madness.

It IS a lot more power than one would expect.... but there are cpus, relays, contactors, and hundreds of sensors drawing power when vehicle is 'on'. Not a problem if the dc-dc is charging the LV system as expected; but a big problem in a hurry if the dc-dc isn't working since our LVB is tiny.... 54amp hr x 12v holds MAYBE 0.5kWhr usable energy. so, 2 hour drive time MAX if the dc-dc isn't working, and much less if you turn on any 12v stuff along the way.

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[Luke]

We're apparently functional after charging the 12 V and resetting/reprogramming "some modules" (no info on which ones) which had lost communication within the car. None of this is a root-cause though, so I can't imagine that things are solved. Why did the 12 V go dead in the first place? How does the "electrical system drain; service required" message relate?

I'm waiting one more day for the car since they somehow hadn't noticed the "2nd key fob for job1s" that the social media team here noticed as soon as I messaged them. So a new fob is in the mail and hopefully they can program it tomorrow.

Any reply from Ford. I’m still having daily warning about the 12V battery drain. I want to know what trouble awaits me.

 

[jbooth]

Nothing useful I'm afraid.

We haven't had more electrical system drain messages since it died/modules were "reprogrammed because they weren't communicating". I would take it from that, that the electrical system drain message was a sign the car was going to strand us and suggest you should probably get it in to a dealer.

You should probably be prepared to be persistent. Ours was in for that message and they did a TSB module update, but clearly that didn't prevent a problem in the future. Related? Hard to say.

We didn't have that message for the first 6-8 months of ownership. We only had it show up after some of the early 2022 software update customer satisfaction programs. That means there was a change shortly before it showed up -- so was it an existing problem, or did it show up because of the work that was done (bad update, partially/incorrectly done updates, incompatible/untested version pairings)?

The dealer who did the work on my car was... less than transparent about things.

 

[JimmyMachE]

OBD2 bluetooth dongle will show the status of the 12V battery, and average parasitic drain when car was locked (quiescent average mA). If some modules are stuck, parasitic drain will probably be much higher than 50 mA.
https://www.macheforum.com/site/thr...acts-and-info-thread.18143/page-8#post-431762

 

[jbooth]

OBD2 bluetooth dongle will show the status of the 12V battery, and average parasitic drain when car was locked (quiescent average mA). If some modules are stuck, parasitic drain will probably be much higher than 50 mA.
https://www.macheforum.com/site/thr...acts-and-info-thread.18143/page-8#post-431762

22 mA this morning when I remembered to check. 14.5V on the 12V system, but also only 82% charge on the 12V and it wasn't budging up or down in the couple minutes I spent scrolling until I found quiescent in that list of doom.

It looked by some of the other readings like DCDC was active and I found it suspicious that the 12V wasn't charging or discharging. Car was on, parked, not plugged in, after running my son to school.

 

[JimmyMachE]

22mA standby drain is a good result.

14.5V means the 12V battery was charged. You can see the 12v battery current flow in amps, on dashboard screens or on the long list in Car Scanner. The 12V battery charging current is often only 1-2 amps, it takes a while to raise the 12v battery by 1% SOC.

 

[Bongjovi]

I have long been of the opinion that software updates are causing most issues that the Mach e’s are experiencing.

I just had this pop up on the day I received this update. Anyone else have the issue pop up when update occurred?

 

[mwtechy]

I have long been of the opinion that software updates are causing most issues that the Mach e’s are experiencing.

I just had this pop up on the day I received this update. Anyone else have the issue pop up when update occurred?

There is no way to know this. I had a software update a few days before my 12v died. Given that they replaced the BECM I would assume it somehow damaged things during that update but again there is no way to know. Maybe this will help but I doubt it since it hasn't moved since introduced https://www.congress.gov/bill/117th-congress/house-bill/6570/text

 

[jbooth]

22mA standby drain is a good result.

14.5V means the 12V battery was charged. You can see the 12v battery current flow in amps, on dashboard screens or on the long list in Car Scanner. The 12V battery charging current is often only 1-2 amps, it takes a while to raise the 12v battery by 1% SOC.

I'm betting 48mA standby drain is a getting-on-to-being-bad result. Especially when I say that was after a 20 minute drive and that the % of the 12V was only 67%, so it would have been lower when I powered up. Also, for some reason, the car didn't charge the main battery overnight, despite charge settings that said it should have, so that's suspicious.

I do have a service appointment (with a different dealer) and they will hopefully actually complete 21P22 since that has some 12V charge fixes in it.

No "electrical system drain" messages on the dash yet.

 

[jbooth]

A few hours later after a 68->80% HV charging session, 46 mA drain and only 69% charge on the 12V. Seems like if it was charging the 12V it should have made more than 2% progress over six hours, especially with a nice juicy 40A/240V circuit available.

 

[JimmyMachE]

LVB Current parameter shows how the 12V battery is charged, often with 1-1.5 amps only.

I hope you disconnect the obd2 dongle when leaving the vehicle? Any remote external services active? Although 40-50 mA is relatively high, seems common for many MMEs.

 

[jbooth]

Yes I disconnect it and no services other than fordpass.

When the car is on it does seem to be charging the 12V (I've see LVB Current in that range). The bigger issue is I think it isn't bothering to charge the 12V at appropriate times.

I've got an old version of the BCM (dealer failed to do 21P22 completely) and am Job 1. A bunch of other little stuff keeps creeping up, seemingly a certain amount of time after the 12V was disconnected, like the passenger door refusing to lock or unlock until some other door (or the fob) does. Makes me suspicious of the quiescent drain differences across the same time period.

 

[jbooth]

Well its at the dealer and they're presumably working on it but still... that's not reassuring.

 

[Mach-Lee]

Well its at the dealer and they're presumably working on it but still... that's not reassuring.

They did most of the 21P22 updates today including BCM, but they missed a few including ABS (somehow the powertrain series let them skip that one?), OBCC, and RFA. I'd also recommend getting the GSM update while you're there.

 

[san]

Is it possible to upgrade the 12v battery for one that has a higher overall capacity and avoid these LVB issues?

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