Dead Car Thanks to Cold Temps Causing HVB Module Errors

[DevSecOps]

The dealer started working on the car yesterday. They were able to turn it on and drive it into the shop on its own power. My only guess as to how that was possible is the fact that the temp went up about 20 degrees to the low 40s, so last weekend's brutal cold wasn't wreaking havoc on the car anymore. It's still showing over 20 different codes, so they are taking their time going through all of them and are supposed to give me another update today.

They should be able to find the issue but if they call you and say they haven't found the root cause you might want to tell them that similar problems were diagnosed with a PIN test of the BECM.

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[DevSecOps]

Followup ... After about 5 hours working on the vehicle on the 8th they landed on this:

Make: Ford
Code: P0DA8
Definition: Hybrid/EV Battery Voltage/Drive Motor A Inverter Voltage Correlation
Description: The TCM continuously monitors voltage at the motor and the generator inverters.

The TCM also checks the controller area network (CAN) communication bus for a voltage message from the battery energy control module (BECM). This DTC sets when the measured voltage does not match the voltage received in the CAN message or is outside the calibrated limits.

Cause:

• Damaged high voltage cables
• Damaged inverter voltage sensors
• Damaged BECM

After that they did perform a Pinpoint test so looks like they should find it for ya.

 

[Rabidsquirrel22]

Followup ... After about 5 hours working on the vehicle on the 8th they landed on this:

Make: Ford
Code: P0DA8
Definition: Hybrid/EV Battery Voltage/Drive Motor A Inverter Voltage Correlation
Description: The TCM continuously monitors voltage at the motor and the generator inverters.

The TCM also checks the controller area network (CAN) communication bus for a voltage message from the battery energy control module (BECM). This DTC sets when the measured voltage does not match the voltage received in the CAN message or is outside the calibrated limits.

Cause:

• Damaged high voltage cables
• Damaged inverter voltage sensors
• Damaged BECM

After that they did perform a Pinpoint test so looks like they should find it for ya.

That's great info. I'll keep updating the thread as I get updates from them on the repair process.

 

[AlpaChino]

Thanks for keeping us updated here @Rabidsquirrel22 . I think we are all going to be learning something from your experience, as bad as it has been.

Any updates from the dealer since yesterday? Hoping for the best for you.

 

[kltye]

Also, which dealer is this? I'd love to know whether to avoid them should I need service with my MME in the future ??

 

[dtbaker61]

I hear ya, the only reason I did is because of all the reports of LVB problems. Decided to pull the covers and connect a charger for a couple days to avoid problems caused by the car sitting for weeks and weeks.

Best tip I can give you is that the back cover has to come off first because it overlaps the side covers. I think you can get by with just partially lifting the right side, but they will crack if flexed too much.

just bring a drill with a 2" hole saw.... much quicker than pulling the covers.

 

[dtbaker61]

Well this day has turned out to be pretty horrible so far. I wasn’t able to get the vehicle jump started and moving again, so I used Ford roadside to call a tow truck. The first one they sent was a big flatbed that wouldn’t fit in the parking structure. Makes no sense that they let you specify where the vehicle is parked and if there is low clearance yet they ignore those details when dispatching a vehicle. So I call again and get another tow truck after specifying that I need something small enough to fit in a tight parking structure. The second row truck arrives and is yet another huge flatbed. So I call Ford roadside again to have them change to another service. Well I just got the call from the third tow truck that he’s en route, so I specifically ask him if he’s in a truck capable of fitting in a parking structure. Nope! Yet another full size flatbed….
At this point it’s been over 6 hours and I’m freezing my behind off.

Has anyone been able to fix these 12V battery issue on their own without a trip to the dealer. Would a trickle charger revive it? I’m really sick of dealing with Ford’s incompetent customer service and trying to get a tow. If I can just get the vehicle moving again I can take it to the dealer myself.

so yes, IF you have a dead 12v, you could try:
- getting access to the connection points (see 2" hole saw recommendation)
- connecting 'regular' jumper cables from any running vehicle for a good 20 minutes to charge your MME 12v

....then try starting

 

[dtbaker61]

The thing that bothers me about most of these posts is that there's no resolution from the OP. So when someone says they have an issue there's an immediate jump to conclude that the LVB is at fault. For some of us who practice critical thinking. we challenge those ideas for the sake of understand the underlying problem or getting to the truth. We want to know the resolution, the voltage etc.

So, my ask of rabid is that he please let us know the outcome and get a reading of the voltage. I'm not saying it's not the LVB, but it could be any number of things. He has full accessory power, which is different from most of the other reported LVB issues.

....yes, bizzarre really.

I'm thinking dc-dc or HV voltage regulator.... but I'm not thru the thread yet.

 

[dtbaker61]

Holy crap, I just realized that the referenced iOS widget doesn’t need an OBD2 sensor plugged into the MMe - it’s phone only.

I guess I figured if FordPass didn’t tell me about my low voltage battery‘s state of charge, any application associated with it wouldn’t tell me either.

Maybe I’ll stop using the battery tender, unless/until I need to (though I’m still unclear based on the above, how low is too low).

less than 11.9 is too low, and the HV is supposed to wake up and dump some energy into the LVB

 

[dtbaker61]

That's great info. I'll keep updating the thread as I get updates from them on the repair process.

ahhhh, so perhaps a fault in HV regulator prevents the dc-dc converter from coming on to maintain the 12v.

..... when you DO get an actual fix, can you go back to edit the top post to summarize so people don't have to read thru all the intermediate stuff unless they want to?

 

[Rabidsquirrel22]

The update I received today was that they've been in contact with engineers at Ford and were instructed by them to replace the BECM and a wiring harness. Both parts are backordered, so no idea when I will be getting the car back but its progress.

 

[Rabidsquirrel22]

Also, which dealer is this? I'd love to know whether to avoid them should I need service with my MME in the future ??

It's at Fox Ford Lincoln. So far, I have no complaints with their service department. They got me a loaner through Enterprise right away and I've been in constant direct communication with the tech working on my car via text message.

ahhhh, so perhaps a fault in HV regulator prevents the dc-dc converter from coming on to maintain the 12v.

..... when you DO get an actual fix, can you go back to edit the top post to summarize so people don't have to read thru all the intermediate stuff unless they want to?

I'm not really sure what the exact cause of this failure was yet, but I'll retitle the thread when I do. My best guess is some kind of cold weather issue with the BECM?

 

[DevSecOps]

The update I received today was that they've been in contact with engineers at Ford and were instructed by them to replace the BECM and a wiring harness. Both parts are backordered, so no idea when I will be getting the car back but its progress.

Hate to say I saw that coming... And it sucks you have to wait. Good news is that the resolution has worked for others from what I've seen.

The cause of the issue is climate related (below freezing) but it's not because of the LVB. Ford is aware of the issue but can't release any more information on it at this time. I've been told to stay tuned.

 

[Rabidsquirrel22]

Hate to say I saw that coming... And it sucks you have to wait. Good news is that the resolution has worked for others from what I've seen.

The cause of the issue is climate related (below freezing) but it's not because of the LVB. Ford is aware of the issue but can't release any more information on it at this time. I've been told to stay tuned.

Well I just hope the replacement parts contain whatever fix is necessary to resolve this and that they aren't susceptible to the same failure.

 

[dtbaker61]

The update I received today was that they've been in contact with engineers at Ford and were instructed by them to replace the BECM and a wiring harness. Both parts are backordered, so no idea when I will be getting the car back but its progress.

BECM is what exactly?

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