Survey: High Voltage Battery Junction Box issues?

[dtbaker61]

All fixed, working well.
They found a loose C1815C was not fully seated as well.

is this connector inside the battery tray, or external ? i.e. something that can be checked visually without dropping the HV battery ?

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[louibluey]

agm batteries do not generally fail suddenly....

easiest way to monitor is a $10 voltmeter left in an aux power port like the one in the center armrest. It should *never* read below 12.0 v, and should read 14.5v or so when the car is 'on'.

The DC/DC converter runs anywere from 13.4V to 15.1V when MME is on, depends on temperature, and what systems are running. Anywhere in that range when the DC/DC converter is running is fine.

 

[dtbaker61]

The DC/DC converter runs anywere from 13.4V to 15.1V when MME is on, depends on temperature, and what systems are running. Anywhere in that range when the DC/DC converter is running is fine.

yes, absolutely correct.... running e-heat etc may pull the 12v system voltage down as low as 13 when under heavy loads when the MME is 'on' the voltage will ready anywhere between 13-15volts.

When MME is off, system voltage will drop pretty quickly to 12.8 or thereabouts when 'sleeping', and then if you open the Frunk, or doors , you may see a drop to 12.3... The 'proper' operation will wake up the MME if the 12v battery drops to 11.9-12.1v and the HV battery should dump in some energy to get the LVB back up to 12.8 or thereabouts to carry it thru background loads while sleeping.

You should *never* see LVB voltage below 12.0 if everything is working correctly.

 

[JBB_JD]

I hope this thread does not go off the rails - I just caught up today. I had the HVJB problem on April 22 after "Earth Day" charging at EA site (probably a coincidence). Windows stopped working about 24 hours earlier. After 21 days, HVJB has been replaced and MME now drives. Windows still don't work but I took the car home for the weekend. The FE (AWD, extended battery)was produced in 1/2021 and has 15,976 miles on it so probably not a batch of bad parts. The car was at a complete stop and making a right-hand turn when I heard a 'pop' and got "Charge State Error", "Stop safely now!" I was able to get to a parking lot for the tow. I am wondering if 12v issues led to HV issue or if windows was effect of impending HV issue. Interestingly - Windows worked through FordPass app so I am thinking software not fuse. ATM the car is in my garage and no windows, main interior lights don't work, I will hand it back over next week for what looks like 1-2 more weeks of 'troubleshooting'. Advice is welcome, at this point, purchase offers are welcome.

 

[louibluey]

Does the new survey include odometer miles when the incident occurred? I think I'm noticing numbers from 5,000's to 15,000's now.

There was a post weeks or months back that improper MME lifting by the battery rails could damage components such as the HVJB. I guess that's a tough one, because most of us would not be in the service bay to see if or how they lifted the MME.

 

[Mach-Evan]

I appreciate all the effort being put into figuring this out. l had to step away for a bit as my experience with having the HVBJB fail so far from home got the better of me. Have to make the first payment on it and we still don’t have it back after 2 weeks...

I do hope that Ford figures this out as this car is great in so many ways. It will be awful if issues like this end up affecting a bunch more owners.

 

[alangant]

I just noticed that another forum member has experienced a repeat failure, probably of the HVBJB. I'm starting to wonder if there is another part of their Mach-E's that is precipitating their failures, either software or hardware. Several multiple failures out of a relatively small percentage of forum members feels like a clue! (Or not; we won't know until Ford finds the root cause.)

 

[mkhuffman]

I just noticed that another forum member has experienced a repeat failure, probably of the HVBJB. I'm starting to wonder if there is another part of their Mach-E's that is precipitating their failures, either software or hardware. Several multiple failures out of a relatively small percentage of forum members feels like a clue! (Or not; we won't know until Ford finds the root cause.)

Several forum members have experienced repeat failures, at least one has had three. That means Ford is still figuring out the cause. I think it also means not many failures have occurred as a percentage of cars produced. If the failure rate were higher, the likelihood of a solution would also be higher.

 

[alangant]

Several forum members have experienced repeat failures, at least one has had three. That means Ford is still figuring out the cause. I think it also means not many failures have occurred as a percentage of cars produced. If the failure rate were higher, the likelihood of a solution would also be higher.

Yes! The combination of this being a rare failure yet several members have had multiple occurrences suggests that some condition in those vehicles may predispose them to the failure. Of course, I have no idea what that might be!

 

[mkhuffman]

Time will tell if your conjecture proves accurate. Knowingly producing defective cars is a bad business practice, so hopefully you are wrong about that. Maybe this year we will find out the true story.

I think the reason Ford is investigating failures isn't about customer service, but an attempt to nail down the cause. But it is conjecture on my part as well.

 

[TRP]

Just got an email from NHTSA asking the following questions:

Can you please answer the following questions:

1. How long, after the error notice, did it take for the vehicle to loss power?
2. Were you able to use your hazard lights?
3. Was there any power to the vehicle?
4. Were you able to restart the vehicle?
5. Was your vehicle towed to the dealership? If so, please provide maintenance documents.

 

[JBB_JD]

Just got an email from NHTSA asking the following questions:

Can you please answer the following questions:

1. How long, after the error notice, did it take for the vehicle to loss power?
2. Were you able to use your hazard lights?
3. Was there any power to the vehicle?
4. Were you able to restart the vehicle?
5. Was your vehicle towed to the dealership? If so, please provide maintenance documents.

I got the same. I will provide as much as possible.

 

[TRP]

I got the same. I will provide as much as possible.

Same. I was not driving mine at the time, the service tech was. So I really didn't have much firsthand info to pass along other than the paperwork

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