Deafeningly Loud Vibrating Car

[Malacandra]

This is not a problem I'd ever read about here before… I just got into my car and after noticing that it wasn't connecting to my phone's CarPlay (which is surprisingly rare) I noticed that Sync 4 was frozen entirely. As I was trying to remember the particular button combination to reboot Sync 4, it did reboot… but when it came online my car was making deafeningly loud knocking noises and shaking violently!

It felt like a jackhammer was nearby… and most alarmingly, when I turned the car off, it continued unabated. I tried turning my car on and off again, at which point I needed to get out of there. Like I said, the sound it was making was deafening, and the experience was more than a little bit scary. Fortunately, this happened in front of my house.

I backed away from the vehicle about 25 feet because it genuinely seemed dangerous to be around. Even at that distance I could feel the knocking (of what I'm assuming was my motor getting banged up) coming up through the pavement.

Eventually, after several seemingly interminable minutes, it stopped.

I've arranged for a flatbed tow to my dealership via Ford Roadside Assistance which should be arriving tomorrow morning. I'm not looking forward to trying to get in there and engage Tow Mode.

Perhaps coincidentally, I just had my car there on Monday for the 23B50 service, at which time they also did the 22P31 recall.

I've hung around this forum for a while, but I don't remember hearing anyone else have anything like this happen. Any thoughts?

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[generaltso]

Could be a very low 12V battery making the amp go crazy.

 

[Malacandra]

Could be a very low 12V battery making the amp go crazy.

That'd be a hell of a failure mode for a low battery. I'm legitmately wondering if my motor is in shreds.

 

[thekat03]

Something like a stick stuck in the cooling fans, maybe? Hopefully it's something that benign, rather than a motor shredding itself.

 

[highland58]

Do you see any damage to the shutters below the front bumper? Could an animal get caught in there while you are driving down the road? If so, maybe it was thrashing around causing the noises and shaking? I've heard of that happening. Just saying...

 

[Maquis]

There have been reports of the sound system going haywire to the point of emitting max-level, hearing damaging sound for cars with Sync 4A.

 

[Malacandra]

Do you see any damage to the shutters below the front bumper? Could an animal get caught in there while you are driving down the road? If so, maybe it was thrashing around causing the noises and shaking? I've heard of that happening. Just saying...

This occurred as I was starting up: I wasn't moving at all.
But, no, the shutters are closed and look fine.

 

[Malacandra]

There have been reports of the sound system going haywire to the point of emitting max-level, hearing damaging sound for cars with Sync 4A.

That's interesting, my initial thought was that it was coming from the sound system. When I exited the vehicle, usually the sound system goes off, but if it were truly haywire, maybe it wouldn't have. And I guess if the bass were going nuts, I'd have that sensation of feeling it through the pavement.

Given the placement of the woofer, it'd be natural for me to think that it was coming from my RWD motor, as well.

I'd certainly rather it was a berserk sound system than my motor.

And how loud was it? My Apple Watch sent me a warning notification about noise in excess of 90 db that could damage my hearing.

 

[Malacandra]

I just tried starting up my car again… and it started up fine. Maquis seems to have been correct, and this was my sound system having gone completely batshit.

 

[Maquis]

I just tried starting up my car again… and it started up fine. Maquis seems to have been correct, and this was my sound system having gone completely batshit.

Here’s a link if you want to research further:

https://www.f150lightningforum.com/forum/threads/dangerous-b-o-sound-system-issue.9254/#post-178526

 

[Mirak]

Could be a very low 12V battery making the amp go crazy.

Ding ding ding.

 

[Malacandra]

I just wanted to circle back and thank everyone for your help. It saved me an uneccessary tow… to say nothing of my stressing over my motor.

Just to follow up: after starting up again and not seeing the problem recur, I later took my first drive with my OBD2 scanner attached, monitoring my 12V battery. Its voltage was steadily around 14.4 and started with a state of charge of 60% - which isn't high, but doesn't seem like a tapped out 12V battery, either.

Those are not unusual numbers for me. I work from home, so mostly I do short intra-city jaunts during the week, with the bulk of my driving over the weekends: and some weekends are light driving, too. So I've seen my 12V state of charge in that neighborhood before. Not ideal for OTA updates, I know…

Sometimes software just gets in a mood. Now I have the Sync reboot cheat code memorized, and if it happens again, I'll put in my noise cancelling earbuds in and reboot Sync 4.

And fortunately, it doesn't sound like I blew out any of my speakers.

 

[azerik]

The way this B&O can behave is baffling sometimes. I wonder if the start up ‘dung dung dung’ became ‘whomp whomp whomp’ as it tried to play the animation.

 

[Mach-Lee]

The amplifier does not like low voltage, and it can enter a reboot loop in which it keeps thumping. I believe it has to do with an excessive voltage drop from the battery. A battery that has been sitting at a low state of charge for a long time will have a high internal resistance due to sulfation. The power suge on start up could dip the voltage below 10.0V and trigger these effects.

This battery should be fully charged with an external charger to 100% to clear out all sulfation and reduce the internal resistance.

 

[Malacandra]

The amplifier does not like low voltage, and it can enter a reboot loop in which it keeps thumping. I believe it has to do with an excessive voltage drop from the battery. A battery that has been sitting at a low state of charge for a long time will have a high internal resistance due to sulfation. The power suge on start up could dip the voltage below 10.0V and trigger these effects.

This battery should be fully charged with an external charger to 100% to clear out all sulfation and reduce the internal resistance.

That sulfation can't be cleared out any other way? There's no way for the HV battery to properly maintain the 12V battery? Or leaving the car on a live Type 2 charger?

Admittedly, this would be less of an issue if Ford hadn't made the 12V battery so damned difficult to access.

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