Car Bricked While Driving. Any Thoughts on This

[Garbone]

I really need to get under my frunk and check these things... A little torque and dielectric grease for good measure.

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[louibluey]

Remarkably common.
The lower ball joints on our Jeep Wrangler weren't torqued to spec and start making a clicking noise. There is a TSB on this and as soon as I mentioned the symptom the service advisor knew what the remedy was right away.

Similar with the turbos on the Super Duty trucks. Those bolts were known to come loose on some vehicles.

That stud was marked, which means the digital torque wrench illuminated green when assembled. Either the spec is too low or the stud had a burr on it and it caused the wrench to read incorrectly. Usually the tool will identify damaged threads but in this case it was missed.

It is probable that several vehicles left the factory with this issue. How many is anyone's guess.

My thought that the nut was not initially properly tightened was just speculation, I do not know that. @SnBGC gives some other possibilities too. Or, maybe that particular stud or nut is defective. Possibly not cracked or stripped, or probably the OP would not have been able to tighten it.

Even though it suggests a mistake, the properly tightened cause is in some way the nicest, because the fix is simply to tighten the nut on the stud to the proper torque value.

Other less likely possibilities, some of these nuts have patterns on the surface to cause them to better lock when tightened to spec, those (if this nut has patterns, like ridges and peaks), could be defective or missing. Could be the wrong nut, defective metal (manufacturing of the nut problem), not made to spec, etc. Damaged or defective threads on the stud, other stud problems, etc.

My guess is that that nut simply was not properly tightened at assembly, but that is only a guess. If it was not properly tightened at build, then it might have eventually vibrated out the four turns the OP reported. Eventually the lug or other electrical surfaces moved apart enough (vibration, bump in the road, and/or maybe some dirt, corrosion, or contamination working in between the contact surfaces) to open the high current circuit.

 

[krafty81]

@Jon Glad you're back up and running, and safe. Is there any reasonable risk of electrocution when tightening these connections? Any saftey protocols we should consider when working here if/when necessary?

Asking for a friend.

Edit: I can't say I know exactly how you feel, but just yesterday my driver's door would not open after 5 or 6 button presses, and unlocking using the FOB. I felt my temperature immediately rise and the "oh shit" thought popped up in my head. I can only imagine what you felt. Sorry you had to experience this.

That drivers door thing is a known glitch that I am told will be fixed by a dealer update.

 

[krafty81]

I would be interested to know if anyone found this problem on their own cars after further inspection.

 

[Mach-Lee]

I'm back up and running no thanks to Ford or 4 different tow companies. After 6 hours and no tow, I decided to have a go at it. BTW, It's a pain in the ass to remove the frunk with minimal tools on the side of the road.

The wire on the right was reading 1.9 volts on the terminal but 12.5 on the actual wire. It took about 4 full turns to tighten it up.

Please be sure to report this to NHTSA, as it is a major safety issue (link below). You were able to get it stopped safely without power steering or brakes but a lot of people might not have been able to. Very concerning since the blue paint dot is present, meaning it slipped past inspection.

https://www.nhtsa.gov/report-a-safety-problem

Surprisingly the battery junction box (BJB) is not in the service manual, so I couldn't find a torque spec. My guess would be 11 Nm.

 

[blkadr08]

Wait…..You turned a corner at 55 MPH? Am surprised any batteries are still in the car.

 

[RMoore]

Amazing story, and impressive save by @Jon both in terms of keeping control of the car and getting it back up and running (did your wife bring you a voltmeter in addition to some tools?).

I'm still a bit confused by the location of the loose nut holding that wire. Is this in that same jump spot that several have made accessible via drilling holes with a hole saw? Can you get access to that nut through those holes or do you have to remove the frunk liner?

 

[SnBGC]

Amazing story, and impressive save by @Jon both in terms of keeping control of the car and getting it back up and running (did your wife bring you a voltmeter in addition to some tools?).

I'm still a bit confused by the location of the loose nut holding that wire. Is this in that same jump spot that several have made accessible via drilling holes with a hole saw? Can you get access to that nut through those holes or do you have to remove the frunk liner?

The beauty panel has to come out and maybe the tub too. The side cover of that junction box needs to be removed to get to those nuts. At least that is how it looks to me in that photo...

 

[Jon]

I would not want to win this award. This situation is terrifying, I would freak the hell out.

Not an award I wanted

 

[Jon]

Wait…..You turned a corner at 55 MPH? Am surprised any batteries are still in the car.

Don't think of it as a right turn. It was a relatively sharp, long turn on a road with a 55 mph speed limit. Something I've done everyday for years with cars, truck and jeeps. It certainly isn't a challenge for the Mach-E.

Unless it bricks.

 

[Jon]

Amazing story, and impressive save by @Jon both in terms of keeping control of the car and getting it back up and running (did your wife bring you a voltmeter in addition to some tools?).

After the 2nd truck couldn't tow me, I went to my work and borrowed tools including a meter from my techs.

 

[Edw]

Wondering what happened and what's the problem with the car after further inspection

 

[agoldman]

A few is a fluke. many is a recall.

 

[louibluey]

Amazing story, and impressive save by @Jon both in terms of keeping control of the car and getting it back up and running (did your wife bring you a voltmeter in addition to some tools?).

I'm still a bit confused by the location of the loose nut holding that wire. Is this in that same jump spot that several have made accessible via drilling holes with a hole saw? Can you get access to that nut through those holes or do you have to remove the frunk liner?

The nut in question (second picture below, right, red cable) is only accessible/visible after the BJB fuse box is rotated and lifted out of the way: The red plastic safety cap (hat), second picture is the 12V jump point (under the "+" hole in the cover we made), which is just above the nut in question. hey, there is no blue mark on my nut!

Benjamin has a good video that shows how it all comes apart, skip ahead to 8:42 (then watch the entire video if you have never removed the frunk tub and want to do it).

A couple of items of caution, the WSM (work shop manual) does suggest removing those two multipin connectors from the face of the BJB (the main/frunk 12V distribution fuse box). I found that if I was gentle, I could leave them connected and gently move the wire harness. Also, the frunk tub bolts can bind, be gentle and careful removing and reinstalling them, it does not take much force to break one of those bolts. I worked in there so many times, I gently re-tapped all of those holes.

Frunk removal, access to 12 V battery and to under hood fuse box - VIDEO
https://www.macheforum.com/site/thr...-under-hood-fuse-box-video.10722/#post-268204

 

[Maquis]

The nut in question is only accessible/visible after the BJB fuse box is rotated and lifted out of the way:


Benjamin has a good video that shows how it all comes apart, skip ahead to 8:42 (then watch the entire video if you have never removed the frunk tub and want to do it).

A couple of items of caution, the WSM (work shop manual) does suggest removing those two multipin connectors from the face of the BJB (the main/frunk 12V distribution fuse box). I found that if I was gentle, I could leave them connected and gently move the wire harness. Also, the frunk tub bolts can bind, be gentle and careful removing and reinstalling them, it does not take much force to break one of those bolts. I worked in there so many times, I gently re-tapped all of those holes.

Do you remember the thread size of those bolts? I want to make sure I have a tap.

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